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    My Journey through the Astronomical Year

    Think of this as a "companion text" to this, the main web site. Not required reading, butI hope you'll find it interesting and helpful.

Events February 2013 – now that’s close but Mercury will be more fun!

Here’s a prediction: The news media will focus about mid-month on a tiny object you can’t see – and ignore a dazzling appearance by zippy Mercury and its meeting with Mars that you can see!

The tiny object you can’t see is asteroid 2012 DA 14  and it will get all the attention because it will be passing very, very close to Earth – well, very close in space terms – something like 18,000 miles in real terms.  No, don’t get nervous – it won’t hit us. (Of course, I’ve read three different predictions of how close it will come, but what’s a small error among friends 😉 Anyway, to put that in perspective, that’s about 60 times farther from us than the International Space Station, but closer to us than our geosynchronous satellites orbit and roughly one-twelfth the distance to the Moon.

NASA chart - click for larger image

NASA chart – click for larger image

Yep, that’s close. But when it happens, this asteroid – which is roughly about half the size of a football field – will be magnitude 8 – barely visible in good binoculars – and at that, visible only to observers in Europe and Asia who look in just the right place at just the right time.  (To find out where to go – and what to input – in order to learn where and when to see it, read this Sky and Telescope post.)

Now Mercury is a sight worth seeing – and not half as challenging

OK – a much, much easier target, though whimsical and quick in its own right – is Mercury, which does a little dance with Mars early this month before climbing into easier view a week later – then doing a heavenly Cheshire Cat act andvanishing almost as quickly as it appeared, which is why we frequently put the word “fleeting” in front of the name “Mercury.” And finding Mercury low in the southwest will be a great warm-up exercise for Comet PanSTARRS – scout out a good observing spot with unobscured western horizon to see Mercury and you have your ring-side seat for Comet PanSTARRS in March!

Start on February 7th and/or 8th

Mercury and Mars on the evening of February 7, 2013 about half an hour after sunset.

Mercury and Mars on the evening of February 7, 2013, about half an hour after sunset.

Here’s the drill:

  • Find an area with an unobstructed western horizon.
  • Go out just before sunset and note where on the horizon the Sun sets – it will be about halfway between west and southwest.
  • Wait half an hour and look for Mercury to emerge in the twilight less than a fist – about seven degrees – above the horizon and just a tad south of where the Sun set.
  • Use binoculars. Though you probably will be able to see Mercury with your naked eye – it is magnitude minus one –  Mars at magnitude one (more than six times fainter) will be much more difficult. But if you can find Mercury in your binoculars, you should see Mars as well. One quibble – they are very close to each other, and you may need to mount your binoculars on a tripod to split them – or even use a small telescope. Exactly how close depends on exactly where you are viewing from – they will be a bit closer for viewers on the West Coast than for those on the East Cast of the US.

As the twilight deepens they will be easier to see – but at the same time they will be getting closer to the horizon and thus more difficult to see because you are looking through more disturbed air at that point.  This is exactly the kind of race you are likely to have next month with Comet PanSTARRS, which will be near the western horizon after sunset and will get easier to see as twilight deepens – and yet, more difficult to see as it moves lower. With such objects there is always a time – totally unpredictable because it depends on local conditions – when you have the best view.

If the weather doesn’t cooperate, try the same drill on either of the next two nights. Mercury will be zipping by Mars. They actually are so close on February 8 it will take a small telescope to “split” them – they will be like a double star.  On February 9 Mars will be below Mercury and should be easy to see again in binoculars.

Best View of Mercury Alone

From the 11th – when Mercury is quite near the Moon – to the 20th, Mercury will be quite easy to see.

On the 11th it’s about five degrees below a very thin crescent Moon – should be able to just squeeze the two in a typical, low-power binocular field of view.

Each night Mercury will continue to be higher at the same time – about 30 minutes after sunset – BUT it is toying with us because as it gets higher it also gets dimmer! On the 11th it is still about minus 1 in brightness.  By the time it reaches its peak in height – around the 16th-to-18th – it has dropped to near magnitude zero. It continues to be quite high up through the 26th, but by that time it has dropped to magnitude 2 – a real challenge to pick out in the twilight.

Bottom line – try to catch it near Mars – that’s really fun. And if you miss that – try to catch it between then and the 19th or 20th. Oh – and if you do have a small telescope, it will make an interesting sight during these twilight hours. Talk about the Cheshire Cat, it will be smiling at us – really! Around the 12th it will look a bit like a quarter moon – half  lit. Twelve days later it will be just a thin crescent – which is why, of course, it is getting dimmer! So the smile gets bigger as the celestial cat vanishes. Oh my!

What else is there?

Well you can’t ignore Jupiter, high in the southeast evening sky with its four major moons continuing to dance about it. It resumes its eastward movement against the background stars, very slowly moving closer to Aldebaran.

And Saturn is putting in a solid appearance in the morning sky. At mid-month it is due south and about 35 degrees above the horizon two hours before sunrise.

And on the moonless evenings early – or late – in the month, don’t miss the chance to see the Zodaical Light.  Best time to look is 80 minutes after sunset. It will be a faint, conical glow rising up from the western horizon – about the brightness of the Milky Way.  You do need skies free of light pollution to pick it out. For more on the Zodaical light, see this post from last year – scroll down to the heading “Basking in the Zodaical Light.”.

Events December 2012: Mercury, Meteor Shower, Dwarf Planet, Jupiter, and more!


OK, so the meteor shower might be a snow shower, it being December and all, but we also get  an especially nice apparition of Mercury with Saturn and Venus guiding us to the elusive planet. And if that’s not enough, we have the ever reliable Winter Solstice – start beating the drums to bring the Sun back out way, please – and the King himself, Jupiter dominating an already brilliant eastern evening sky  plus a nice asteroid pass to accompany a not-quite-as-bright Dwarf Planet – you know, one of those Pluto-like things! Whew – out of breath just thinking about it all.

Here are the links to one  event at a time if you want to jump straight to the details.

Geminid Meteor Spectacular – December 13-14

First, please meditate on this: Ask someone who is 50 miles away to strike a wooden kitchen match. Can you see it? Of course not. But that’s what’s going on when you see a meteor flash across the sky! Chances are it is from a particle about the size of the head of a kitchen match – or smaller –  and it is burning up as it hits the atmosphere above you travelling at up to 100 times faster than a rifle bullet.The result? A very, very bright “match.”

And now the Geminids – As you may know, I really don’t like that word “shower.” It builds expectations out of proportion usually, but if you have clear skies on the night of December 13-14th it’s worth digging that folding  chaise lounge out of storage, wrapping yourself in a sleeping bag – with binoculars and hot beverage handy – and staring up at those wonderful bright stars of winter waiting for some to “fall.”  Hey, if you have an Iphone or Ipad there’s an app for this – no kidding – you can record what you see and ship it off to NASA, thus contributing to scientific research –  all quite painlessly. (Go here for details.)

Oh – and this is the time of new Moon, so the Moon won’t be present to upstage the show with its bright light. The official word goes something like this – expect “about 120 meteors visible per hour for an observer at a dark sky site late on the peak night.”  That’s how Sky and Telescope puts it and those folks certainly know what they’re talking about, but in many nights of meteor watching I’ve never seen anything close to 120 per hour. When that’s the forecast I figure I have a good chance of seeing 20-30 an hour and believe me, that’s a real treat.  Maybe your skies are darker than mine, maybe your eyes are better, and maybe you’re more patient – so maybe you’ll see 120. Me – I will be delighted with a meteor every two-to-three minutes –  if not a quite a shower, that’s a  snappy snow flurry!

So where do you want to look? Up! Any part of the sky  can produce meteors, but if you trace their trails backward you will see they all emerge from the same general section of sky near Castor, the slightly dimmer Gemini twin.  Since they appear to radiate from this area of sky the most meteors will be visible when it is high overhead – and looking in that general direction is a good idea. Here’s a chart for 1:46 am ET -when Castor is at its highest – on the morning of December 14.

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

So does that mean you have to wait until  early morning to enjoy the Geminids? No! But it makes sense that if the radian point is near the eastern horizon – which it is a couple hours after sunset – then you cut your chances of seeing a meteor in half – which still means a very respectable number of meteors.  The higher the radiant point the more chance you have of seeing more meteors. But then, you can’t watch the whole sky at once – even if you have remarkably clear horizons – and one thing about meteors – they are very fast and there’s no instant replay. Blink – or be looking the wrong way – and you may hear the ooohhs and aaaahhs of companions, but you will most likely not see what they saw.

Most meteor showers are the result of the Earth passing through a trail of comet dust  – think of “Pigpen” in “Peanuts” and you get the idea of comets leaving a trail of dust. But not the Geminids. They’re something of a mystery, but the current theory is that they come from a maverick asteroid. To read all about it, go here.

Hey – why not do the observing right?  Go out about 2 am and enjoy a couple hours of meteor watching, then shift your focus to the eastern horizon where Saturnn, Venus, and eventually Mercury will put in an appearance – quite a show, really.

Mercury – an early month, early morning stage appearance with Saturn and Venus

Mercury  reaches longest elongation – distance from the Sun –  on December 4th and while it will be well-placed for another couple weeks, you need to grab the little winged messenger when you can. It pops above the horizon six times a year – three in the morning sky and three in the evening sky, but not all pops are created equal. This happens to be its best appearance for 2012.  As a bonus, brilliant Venus will act as a guide. The two planets will be closest on December 9th when you should be able to squeeze them both into the same low-power binocular field of view. But all month they will be close enough for Venus to help in finding Mercury and Saturn will be visible a bit above Venus.

Of the three, Venus will absolutely dominate in brightness at magnitude -3.9. But Mercury on December 4th will be just a tad dimmer than the brightest star we can see (roughly -0.5) and Saturn is no slouch at 0.65 – and they’re in the southeast with two bright guidepost stars, Arcturus and Spica. Here’s what to expect.

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

December 11th isn’t so shabby either because we get a crescent Moon in the picture as well, though both Venus and Mercury have dropped  down a bit, you should still be able to find them both. Venus will be easy. Mercury – well, you may want to use binoculars, though it should still be visible to the naked eye if you have clear skies – and, of course, an unobstructed eastern horizon. It’s only about half a fist above the horizon at this point.

Click image for larger version. (Created from Starry Nights Pro screen shot.)

The Winter Solstice – Sure it happens every year but it always seems special – December 21

What’s so special about the Winter Solstice? Well, for me it’s a reminder that all life – you and I, plus every animal and plant on this tiny planet depend on the Sun. The Winter Solstice – as seen from the Northern Hemisphere –  reminds me of this because on the morning of December 21 the Sun will rise as far south as it gets. In the next few days it will start inching it’s way back north and that is certainly a good sign. Sure, our seasons lag behind the sky a bit. The worst of the winter weather is yet to come. But the fact that the Sun is on its way back is certainly an encouraging sign. More primitive societies that were in better sync with the natural rhythms of the sky, celebrated this time of year and with darned good reason.

Ceres is Ceres – but you can call it a dwarf planet

“Dwarf planet” was the category astronomers agreed upon in 2006 to fit objects that are big enough to be round, but too small to have cleared the area of their orbit of other objects. That’s what Ceres is and so is Pluto, and three other known objects.  It amazed me that this rather technical decision (I have greatly over-simplified the definition) caused such a stir because it demoted Pluto from planet to dwarf planet. These are simply classifications and in astronomy over time classifications get kind of messy. I mean, stars in the 19th Century  were classified in a nice alphabetical list by their spectra – but then we kept learning more and the list got screwed around  to anything but alphabetical: OBAFGKMLT. What’s more, our Sun – and many other stars that are among the larger ones, is called a “dwarf star!” Oh my – now that sounds illogical, if not offensive.

Oh – and Ceres, the first asteroid discovered (1802) – and largest (952km) – is still often referred to as an “asteroid” because it is a dwarf planet inside the orbit of Neptune where we usually find asteroids – arghhhhhhh! See why I want to just call it Ceres and be done with the naming thing ?  😉

Do click onthis for the full-size image - that's really Vesta as imaged by Dawn, but essentially this is an artists view of what it must have looked like as the Spacecraft orbited the asteroid.

Do click on this for the full-size image – that’s really Vesta as imaged by Dawn, but essentially this is an artists view of what it must have looked like as the Spacecraft orbited the asteroid.  (We didn’t send anyone along in another spaceship to take pictures of the two!)

But Ceres – and even brighter Vesta – have been the subject of an extensive examination conducted by the NASA  “Dawn” spacecraft.  It has spent a year examining Vesta and is now on its was to get up close and personal with Ceres. But you can beta it to it – you can see both Cere and Vesta from your backyard this month with nothing more than binoculars, a few charts, and some determination. Of course your view will be a bit less detailed. The two will appear as stars just below naked-eye visibility. And although it’s about half the size, Vesta is the brightest because it happens to be made of – or have on it’s surface – shinier material.

This is an excellent opportunity for you to test your skill with binoculars. This month they will both look like sixth magnitude stars and thus be easily seen in binoculars – but I won’t underestimate the challenge. The good news is they are well placed near bright, familiar stars and the brilliant planet Jupiter in the evening eastern sky. That makes it easy to find the general area in which to search. The bad news is there are lots of stars up there – especially when you look with binoculars – so you need to really study the charts before you go outside, then do  very careful observing. If you find it one night, it’s  fun to look again in a few days, or even a week or two – because they do change positions rather rapidly while the stars, of course, stay put.

Go here to get a printable chart of the Path of Ceres and Vesta over the next few months.

Now print this chart to use to mark your observations of Ceres and Vesta over the same period.  It’s a chart of the same area of sky covered by the previous chart, but with the position of Ceres and Vesta shown only for December 9, 2012 as viewed from mid-northern latitudes about four hours after sunset. However, while the orientation changes somewhat by date and time, it should serve to track Ceres and Vesta for December and January. Magnitudes of a few selected objects are given in parenthesis to help identify Ceres and Vesta. Before going outside to make your observation, study the chart and determine where you think Ceres and Vesta should be that night.

And as you look at Vesta, get this picture in your mind’s eye – and as you will see at the end, Ceres look a bit different, but how different – well, we’ll see when Dawn gets there!

And here’s the best view we have of Ceres as seen by the Hubble Space Telescope.

Images of the Asteroid Ceres As It Rotates One Quarter
Source: Hubblesite.org

Jupiter – let’s not forget the king of the planets

As some wag commented, our Solar Systems consist of the Sun, Jupiter, and some debris!

It is big – and only Venus outshines it, and yes, with careful viewing you can see one or more of the four Galilean moons using only binoculars. The key is to hold them steady and observe – don’t just look.  A “look” is what most people tend to do at first – that is, they hold the binoculars up and if, in 10 seconds or so, they have not seen the moons, they give up. That is not observing. To observe you need to look for at least a solid minute. That won’t guarantee you see the moons, but just taking a quick look can mean you easily miss them.

They may all be on one side of the planet and they constantly change their relationship with the planet and one another so that even with binoculars you can notice the difference over the course of a few hours. They will look like tiny stars, they will be close to the planet, and they will be roughly in a straight line that passes through the planet’s equator. This line will be pointing upward as the planet rises, level off when it’s near the mid-point of its arc across the sky, and be slanting down as it heads for the western hprizon.

The best way to prepare yourself for what to see – to check to see if you are seeing the right thing – is to go to the Sky and Telescope web site and use the javascript simulator there for your date and hour.  To do that, go here . With binoculars you want the right-side up view. With small telescopes it is much easier, of course, to see these Moons, but a telescope will change the orientation and this script allows you to change that orientation to match your telescope’s view. Here’s a typical example of what you will see.

Events December 2011 – Eclipse, Planets galore, and a very starry Christmas!

Let’s start with that very starry Christmas – I’ll be brief. If you like Christmas lore, the sky certainly cooperates this Christmas with brilliant Venus playing the role of the Christmas Star low in the southwest shortly after sunset. The sky at that time should look about like this:

Click image for larger version - Stellarium screen shot.

Click image for larger view.

And to identify what you’re seeing in the image above, click this thumbnail of the same scene.

Now – without going into great detail, suffice it to say that the Christmas Star lives in the hearts of believers,  as well as those for whom a bright star simply is a charming symbol of the season, as is a decorated tree or wreath. However, theologians and astronomers have put forth various theories over the years about what star, or comet, or combination of planets might be the “star” referenced in the Bible, and I’ve yet to encounter a single, credible explanation that makes me say – ah, that’s what it was!

But what we do have in the Christmas sky every year at this time is an asterism called the “Northern Cross.”  This is our old friend, Cygnus the Swan, who when rising in early summer appears to be flying south. Now he’s diving into the ground in the northwest and his main stars are much easier to make sense of as an upright cross asterism. The other identified stars on the chart  – Vega, Altair, and Deneb – mark the familiar “Summer Triangle,” which gets in one last shot before the wintry blasts descend on us.

And the Star of Bethlehem? Well, this year you might want to choose Venus to represent it as it begins a winter-long – and  brilliant – stand as our “evening star,” warming up the winter western sky with its shadow-casting radiance.

Great lunar eclipse as long as you don’t live where I do ;-(

My friends in Australia will have a great seat for this show on December 10-11. I won’t. Although the farther west you go in the US, the more interesting it gets, especially for early birds.

Essentially, a lunar eclipse starts with a “penumbral” eclipse, and this may give casual readers of various eclipse sites the idea that we in the east will see more than we actually will. Even on the East Coast of the US the penumbral stage of the eclipse will be underway just before the Moon sets – and that’s just half an hour before dawn.  But even under the best of conditions I find  the penumbral eclipse less than exciting – heck, I find it barely detectable. What it means is the Moon is entering the outer – dimmer – part of the Earth’s shadow. This will barely dim its light. And for us on the East Coast this will be especially difficult to notice with the Moon low in the west and us well into twilight.  So I’ve resigned myself to waiting until the next total lunar eclipse  April 14,15 of 2014 – which will be seen here.

But – elsewhere this eclipse  gets a lot more interesting. Here’s how NASA sums it up with a graphic on their eclipse web site – OK, you may need a little rocket science training to read this, but not much – be patient 😉

NASA eclipse details - see below for explanation. (You can click on this for a larger version.)

The important numbers here are in Universal Time.  To translate to your local time  go here.

The Moon enters the penumbral shadow at 11:33 Universal Time – that’s “P1” in the above graphic. For me in Massachusetts, that is 6:33 am on December 10.  For my friend John, in Oregon, that’s 3:33 am on December 10. And for my observing friends in Sydney, Australia, that’s  21:33 – 10:33 pm on December 10. See how things get better and better the farther west you go?

Unfortunately, things don’t begin to get really interesting until the umbral phase begins.  The Moon makes first contact with the dark (umbral) part of the Earth’s shadow at 12:45 UT. That’s 7:45 am for me – well after moonset and sunrise, so meaningless. Out in Oregon that’s 4:45 am, so John certainly should be able to see this phase and should see right up to the early stages of totality, though the Moon will be awfully near the horizon then – 6:06 am local time in Oregon and I imagine twilight will certainly impact the drama.

But the folks in Sydney? They get to see the whole show. Totality begins for them at 01:06 am,  Sunday December 11, 2011, with the Moon high in a dark sky.

And yes, if you haven’t figured it out by now, Europe misses this one.

If you would like to get a better handle on what’s going on – or perhaps share this experience with your kids in a meaningful way, I urge you to build my simple Earth-Moon model. I think you’ll find it fun and instructive.

Getting to know – I mean, really know – a planet when you see one

“What’s the bright star in the west right after sunset?”
I guarantee you I’ll get that question more than once in the coming months. I hope it won’t be from someone who has been reading these posts.  The truth of the matter is, we can see only five planets with our naked eye and one of those five is rare – Mercury. You have to know just when and where to look for it. But the other four are pretty darned easy to recognize on sight if you know a little about their habits and looks.
William Tyler Olcott made this clear in his wonderful  little 1907 “A Field Book of the Stars.”  Here is his short  list of rules – each of which you can put to the test any clear night this month:
If the planet is in the west, and very brilliant, it is safe to assume that it is the planet Venus.
If it is brighter than any of the fixed stars, and it is some distance from the Sun, it is doubtless the colossal Jupiter.
If it is very red it will probably be Mars.
Saturn is distinguised because of its pale, steady, yellow light.
OK, let’s  do a few “for examples.” For example, if you go out on the evening of December 26, 2011, about an hour after sunset, and look to the southwest, here’s what you should see.

Click for larger image - Stellarium screen shot.

Yep, that’s dominant Venus less than a fist away from the 2-day-old crescent Moon and both pretty near to where the Sun set an hour ago.  And when you think about it, you’re always going to see Venus somewhere relatively close to the Sun. From our perspective it swings to one side of the Sun for several months, then to the other side of it, since its orbit is closer to the Sun than ours. This coming winter it will get about as far away from the Sun as it can get, before starting to fall back towards it, so this is a good time to watch it – check on its progress from week to week.
What this means is it will frequently be an “evening star” in our western sky – BUT, though Olcott didn’t mention this – it will just as frequently be a “morning star” dominating the eastern sky before sunrise.
Mercury does the same thing – just much faster and it is doesn’t get nearly so brilliant. Last month it was in our western sky, this month it’s in the east before sunrise.
And how about Jupiter? Well, as Olcott wrote: “it is brighter than any of the fixed stars, and it is some distance from the Sun . . .” He also noted that the planets are always found in a relatively narrow arc of sky – the same one that the Sun and Moon follow – I threw the big arrow into this next screen shot to emphasize how the Moon, Venus, and Jupiter are all on the same path – that is, they are all in the plane of our solar system.
So after you locate Venus, swing your head about some to the south and look higher up. Here’s what you should see. This is for December 26, but with the exception of the Moon you should be able to see roughly the same scene any clear evening this month about 45 minutes after sunset. (OK – it will be easier to see the later in the month you look because Venus will be getting higher each night.)

Click image for larger version. This is a modified Stellarium screen shot showing a much larger area of sky than the previous one with just Venus and the Moon.

Mars, Saturn, Mercury and the Moon – a morning event

Now Mars and Saturn are a bit more problematic.  I agree with Olcott’s descriptions, but I also find it hard sometimes to distinguish between a twinkling star and a non-twinkling one that is the visual signature of a planet – and while I can readily identify star colors, they really are just tints and are not all that obvious to the unpracticed eye. Heck, I know some very experienced amateur observers who just don’t see the colors.
But to see what Olcott means, go out just about any morning this month and look to the east about an hour before sunrise.  I’ve chosen the morning of December 22 for a couple of reasons – first, the crescent Moon is in the sky and will help to guide you – and second, this happens to be the longest night of the year – the Winter Solstice, and so it’s a good time to get out and beat the drums and hope the Sun really is going to turn around again this year – stop heading south and start heading back north to chase away the winter doldrums and warm us up.

Aging Moon joins Mercury, Mars, and Saturn in the morning sky - Stellarium screen shot with labels added. Click image for larger version.

A few notes on this image: First, while Mercury is as bright as Mars, this makes it look even brighter – but it really will appear dimmer because it is so close to the horizon and in the morning twilight.  It’s about one fist away from the Moon and less than that above the horizon and will be much easier to spot if you use binoculars.  Saturn and Mars give us a lesson in color.  First, Saturn – kind of yellowish – is right next to the bluest of stars, Spica.  They both would fit in a single binocular field and Saturn is just a tad brighter.

Mars is just a bit brighter, too, and much higher – but don’t expect to see bright red. Fred Schaaf, writing in Sky and Telescope this month, says Mars plainly shows “its striking orange-yellow hue” to the naked eye this month. Yep.  Go back and forth several times between Mars, Saturn, and Spica and you should get the idea of what colors really are like in the sky. Looking at these three objects in binoculars should enhance the color a bit.

Oh – and this is the other end of that arc – the one represented by the arrow in the previous image, showing the way the planets, Sun, and Moon travel on the same path. Here the arrow should stretch from Mercury – near where the Sun will rise, to Mars. When the Sun rises, this is the general path it will follow.

A note about meteors – not this month, but be ready in early January!

The Geminids (December 13-14) are usually a great meteor shower in mid-December, but  this year the Moon will drown out all but the brightest.

However, here’s a heads-up for early January, 2012. Mark January 4, 2012, on your calendar. The rarely seem Quandrantids (I’ve caught them once and not at their best) will peak around 3 am EST on January 4. This is a shower where the peak can be spectacular – 60-200 meteors an hour– but it lasts only a couple of hours. So it’s rare to have the peak come in the early morning hours for your section of the world when the showers radiant is also at or near its highest point and when the Moon offers little or no interference.

For me a fairly bright 10-day-old Moon sets at 2:55 am – weather permitting – and it will be cold, I’m sure – I’ll start watching about 2 am and plan to stick at it until about 5 am – weather permitting.  This, by the way, is a good lesson in how “annual” astronomy events, such as the Quandrantid meteor shower, frequently become “once-in-a-lifetime” opportunities, for this will only happen if the time of the shower’s peak is just right for your location, and if the Moon isn’t interfering – and last, of course, if the local weather cooperates. That’s a lot of “ifs” and it’s why, when you get an opportunity such as this, you shouldn’t pass it up.

Oh – and don’t forget Algol!

I always check the mid-eclipse times for the coming month –  they vary depending on your location. For me the dates and times that look best are:

  • 12/10/2011 @ 08:46 pm
  • 12/13/2011 @ 05:35 pm
  • 12/30/2011 @ 10:30 pm
That means Algol will be at its dimmest for about an hour either side of those times. To make your own checks, go to the Web calculator found here.
For more details on Algol, go here.

November 2011 Events: Feast in the East – and the West is no Slouch Either!

With the naked eye the planets look like stars and we can follow the path of the five brightest in our skies this month. With binoculars we can add Uranus and Neptune to our list and even see the four brightest moons of Jupiter. (NASA composite image. Click for larger version.)

It’s a feast in the east for November 2011 with Jupiter dominating that section of sky in the evening and Mars and Saturn taking over in the morning. Meanwhile, over in the west we have the Venus/Mercury show developing in the second week of the month.  And how about the middle of the sky? Well, there we have the always challenging-to-find planets, Uranus and Neptune.  Binoculars are a must to sight them. And if you’ve been counting, you know that’s all the planets! (Pluto – well, it’s a “dwarf planet” and it’s heading behind the Sun this month, and even if it were well placed it would be out of reach of the naked eye, binoculars, and even small telescopes.) Add to this a comet and the special fun the moons of Jupiter offer, and it really should be a very good month.

An appetizer: take a 2.5 million year star trek to the Great Andromeda Galaxy

But wait! That stuff is all in our back yard – we can get to any of those planets in a matter of minutes – light minutes, that is! (Light travels around the earth seven and a half times in a second , yet it takes it about 30 minutes to reach Jupiter!)  But early evenings in November – especially when there’s no moon to compete as will be the case in the last half of this November (2011) – offers another special treat for binocular users – the Great Andromeda Galaxy.

The Great Andromeda Galaxy as seen by the Hubble Space Telescope. It won't look quite like this, but you too can see it with binoculars.

This is our neighbor in space –a galaxy much like our own Milky Way. And with dark skies free of the worst of light pollution you can actually glimpse it with your naked eye if you know just where to look. And it really is a glorious sight in even ordinary binoculars, especially when you understand that the small cloud you see is really 300 billion suns and their light is reaching you after journeying for two and a half million years! I don’t mean to detract from the planetary show, but if you have binoculars and clear skies, you really should take this “trek.” It will be especially good during the last two weeks of the month when the Moon doesn’t wash it out.

Review the eastern sky chart in our “Look East” post for this month, then use the chart and instructions below to zoom in on this galaxy – and when you do, give yourself a pat on the back as a genuine star trekker.

To find the Andromeda Galaxy use half of the "W" of Cassiopeia as a pointer. Or take a star hop down Andromeda's Couch, then up a couple of hops as shown. You should be able to fit stars 3 and 4 in the same binocular field of view, then stars four and the galaxy in the same field. Click for a larger version. (Created from Stellarium screen shot.)

(Here’s a printer-friendly, black and white version of the chart above.)

Back to the planets – they  line up like this

  • Jupiter can’t be missed. It’s the brightest “star” low in the east right after sunset.
  • Venus gets started on one of its spectacular appearances during which it will dominate the western evening sky for months.
  • Mercury plays coy and hard to catch, but Venus gives it away as it peeks above the western horizon right after sunset.
  • Mars is getting higher and higher in the morning sky and actually rises before midnight for part of the month. It continues to scoot right along, this month playing tag with the bright, guidepost star, Regulus.
  • Saturn is a morning sky object that will excite telescope users because its rings are at last returning to a favorable tilt from our perspective.
  • Uranus and Neptune are the difficult ones. They are both reachable with binoculars and in prime time, but they are challenging to find.

So that’s the line-up – read on for details. Or jump ahead to what interests you by clicking on one of the links above.

The Feast in the East 1 – Jupiter and the Algol bonus

Jupiter is in its prime – and dominating our prime-time observing – nice and high, nice and big, and with dancing moons that you can even see in binoculars if you can only find a way to hold them steady enough. Fortunately, there are several neat techniques pictured here that you could use to hold any binocular steadier. I used the “rifle sling” technique pictured on that site with my 15X70s and it helped significantly. But no matter what the size of your binoculars, you increase your chances of seeing Jupiter’s moons if you can get them rock steady.

Most binoculars have a threaded center post that allows you to use an inexpensive adapter to mount them on a typical camera tripod. This is good as long as the object you are looking at is not too high in the sky. Once it gets above 45 degrees it’s very difficult to position yourself behind binoculars that are on an ordinary tripod. (Go here to see one example of tripod adapters for binoculars.) So this is a good approach this month up until about three hours after sunset as Jupiter climbs higher each hour.

When you are looking at Jupiter’s moons, it’s fun simply because they are constantly changing position from night to night – even from hour to hour. It’s also fun because they are surprisingly diverse worlds. In fact, the exploration of large moons throughout the solar system has been a constant source of surprise. So I suggest two things.

First, learn more about Jupiter’s moons by going here. (Pay special attention to the four “Galilean Moons” – those are the ones you see.)

Second, use this Javascript utility at Sky and Telescope to figure out which moon is which when you actually observe them..

And while we’re on the subject of handy tools at Sky and Telescope, also use their utility to figure out when it would be a good time to catch the surprisingly elusive Demon Star – aka Algol – when at its minimum. This is something you don’t need binoculars to see – it’s best done with the naked eye. I explained it in more detail last month.

Feast in the West – Venus and Mercury

Venus and Mercury line up almost due southwest with the sun setting halfway between southwest and west. BE SUPER CAUTIOUS! To see these you will need binoculars, but looking at the Sun with binoculars will cause immediate damage to your eyes. So wait 10-15 minutes after sunset, then start your search. Venus should be bright enough even in twilight to see with the naked eye once you know where to look, so it helps to find it first with binoculars. (Prepared form Starry Nights Pro screen shot.)

From roughly the 9th to 22nd of November 2011 Venus and Mercury will appear  in the same binocular field of view about 15 minutes after sunset. They are attractively aligned in an arc or line for just a few days starting on the 9th.  I’ve included Antares because it makes such a nice picture, but it’s more than a magnitude fainter than Mercury and much, much fainter than Venus (magnitude -3.8) and closer to the horizon, so I think it will be a difficult target. You need, of course, an unobstructed western horizon and very clear skies. Fifteen minutes after sunset Venus is less than a fist above the horizon. Half an hour after sunset it’s just half a fist high, and if you haven’t spotted it by then, you probably won’t as it will get lower fast and the closer to the horizon, the more difficult to see.

Please be careful and don’t begin your search with binoculars until 10 minutes after sunset so there’s no danger of catching the Sun in the binoculars and damaging your eyes. As the days go by Mercury stays about where you see it and Venus pulls away to the south, getting higher as Mercury begins to sink.

The Feast in the East 2 – Mars, Saturn, the Moon and stars

Now this is cool!  On November 22, 2011, you won’t have any trouble locating Saturn because it will be within a fist of the crescent Moon with Spica, about one magnitude brighter than Saturn, between it and the Moon. High above them,  Mars has passed Regulus, and is just about the same brightness as Saturn.  But you can find these planets just about any morning of the month, using the bright guidepost stars as your guide. Follow the arc of the Big Dipper’s handle and it takes you to Arcturus. Keep following this general curve and you get to Spica – passing through Saturn on the way.  Both Spica and Arcturus are  bright guidepost stars, as is Regulus. Mars will be within one fist (10 degrees) of Regulus all month. Mars starts out west (above) it on the first of the month, passes closest to it on the morning of November 11, and will be about one fist east (below) it by the end of the month.  Saturn will stay roughly half a fist (5 degrees) from Spica all month, changing position much more slowly than Mars since it is much farther away from us.

Click on image for a larger version. Prepared from Starry Nights Pro screen shot.

Challenge in the Middle – Uranus and Neptune

The early evening of the last half of the month is a good time to look for these planets since the Moon will not offer interference then – but you need to wait until about 90 minutes after sunset so it is completely dark.

This is where knowledge of the sky certainly helps – with a little knowledge it’s as easy as one, two – to find Uranus; and one, two, three to find Neptune. Here are the steps

One – Get your bearings.

Know the sky in the vicinity of these two planets. In particular you want to locate a relatively dim asterism known as the “Circlet” to guide you to Uranus, and two others, the “Water Jar” and “Arrowhead” to find Neptune. The starting point, however, is an asterism that should be familiar to you – the Great Square – and if it isn’t, please go to the “Look East” post for this month and locate it.  Then study the following chart – click on it to see the larger version.

Step one - get familiar with the big picture. The red circle between Uranus and Neptune is the field of view of typical, low-powered, binoculars - good tools for finding these objects. The Great Square and Jupiter should be easy to find because they're both bright. The "Circlet" is fourth and fifth magnitude stars that you need to be away from light pollution to find, but even in light pollution you can spot them with binoculars. However, the whole Circlet will probably not fit in your field of view. The Water Jar will fit in the typical binocular field and so may be an easier target. What I call the "Arrowhead" is the constellation Capricorn. The star at its northeastern corner is bright enough to see even in light-polluted skies and so is a good starting point for finding Neptune. Click image for larger version. Prepared from Starry Nights Pro screen shot.

Step 2 – Zoom in on Uranus . . .

Assuming you have located the Circlet, now turn to this chart. The brightness of the planet in comparison to nearby stars is a good guide and will give you some idea of what to look for and whether or not it’s visible in your skies. The numbers on the chart refer to the magnitude of a star or planet. They are given without a decimal point so as not to confuse the chart with dots that aren’t stars. Thus the number “51” means a magnitude of 5.1 – and remember, the lower the number, the brighter the star!

Scan below the Circlet with your binoculars. The little rectangle of fourth and fifth magnitude stars should be easy to pick up and will help you find Uranus. Note that Uranus at magnitude 5.8 is half a magnitude or so dimmer than the stars in the rectangle, but a bit brighter than the 6.3 star next to it. The position of Uranus will change very little during the month. Click on image for larger version.

  . . . or alternative Step 2, zoom in on  Neptune

Neptune is more challenging, but if you can locate the third magnitude star Deneb Algiedi in the northeastern corner of the Arrowhead asterism, you will be well on your way. (It’s on the bright side of third magnitude, so should be fairly easy to find.)

Once again, the numbers next to stars are their magnitudes with the decimal point left out. So Neptune is magnitude 7.9, for example. It will be right near the edge of visibility in low power binoculars and you'll need the next chart to pick it out from the background stars. Click image for larger version. Prepared from Starry Nights Pro screen shot.

And now Neptune Step 3 – up close and personal

The bigger – and steadier – your binoculars, the easier it will be to see Neptune. It’s also important that your eyes be dark adapted. You’ll be looking for a faint “star” among several. Here’s a close-up chart.

Click image for larger version. Prepared from Starry Nights Pro Screen shot.

Did I mention the comet?

The comet is one that requires binoculars, but it’s still fun and is unusual in that it will be with us right up to the spring. I’m talking about Comet Garradd which we met at the end of August and start of September when it was hanging around with my favorite binocular asterism, the Coathanger.  Here’s a chart for its path in the last half of November.

At 6th magnitude Comet Garradd is just below naked eye visibility for most of us, but you should be able to pick it up in binoculars as a faint, fuzzy star. I doubt very much that you'll see a tail, but if you do it should point the direction shown in the chart. The chart is for 90 minutes after sunset - look west and find the Keystone of Hercules as a starting point. The second and third magnitude stars - Rasalhague and Rasalgethc, should also be a big help in getting you in the right general area. Arrow shows movement of comet from November 15 to November 30 - a period when the Moon should not interfere with your search. On the 15th Comet Garradd will be about three fists above the horizon 90 minutes after sunset - by the end of the month it will be about two fists. Click image for larger version. Prepared from Starry Nights Pro screen shot.

And if you’re wondering where the November meteors went, the Moon ate them!

Yes, last year at this time we were talking about three minor – but interesting – meteor showers. They were the South and North Taurids and the Leonids.  They’ll still be around this year, but they are weak shares at best, and this year will be especially challenged by the Moon. But for the record, the South Taurids peak November 5/6 late night until dawn; the North Taurids November 11/12th; and the Leonids November 17/18.

Events October 2011: Mars stirs up the Beehive, plus a little LunaSee Jupiter style!

October starts in September – at least when it comes to observing Mars this year! In fact, October 2011 will be a neat month for planet watching with naked eye and binoculars, not to mention a good time to catch the  Zodaical Light, as well as a few Orionid meteors  – and with the first items it’s good to get an early start. By early, I mean you can start your Mars watching near the end of September and this is an early morning event.  But if early morning isn’t your thing, take heart – King Jupiter and his retinue are available evening and morning. (Jump to here if you’re interested primarily in Jupiter.)

Fast-moving Mars

That said, let’s start with Mars because it has been fun to watch in September as it cruised through Gemini and for a brief period made the heavenly twins look like triplets. In October it’s even cooler as it goes ripping through one of the best binocular star clusters – M44, the “Beehive,”  known to the ancients as “Praesepe.” That last name is Latin for “manger” and some saw this as a manger, apparently with hay in it and two donkeys – the Northern Ass and the Southern Ass, eating out of it.

These are handy, relatively bright stars that Mars will pass between. They also  may help you with your Latin, for their more formal names are Asellus Borealis and Asellus Australis.  Seeing them in binoculars may help you pick up  the Beehive if  your light pollution is so bad that you are having trouble finding it, though binoculars certainly should bring it out in all but the worst conditions. Here’s the scene in the eastern sky early in the month a couple hours before sunrise.

Click image for a larger version. This is the view looking east about two hours before sunrise on October 1 when Mars will be about 30 degrees above the horizon - that's three fists. It will be about halfway between Castor and Pollux in brightness and should have a red tint very similar to Betelgeuse in Orion. (Chart prepared from Starry nights Pro screenshot.)

You can download a printer friendly version of the above chart to use under the stars here.

Here’s what typical binoculars – with a 7-degree field of view will show when you zoom in on Mars on October 1, 2011.

The view through binoculars. Click image for a larger version. Mars will be much brighter - and redder - than the stars in the same field. The brightest stars will be Asellus Borealis and Asellus Australis and they are about the brightness of the stars in the handle of the Little Dipper, so will not be seen with the naked eye unless you have skies relatively free of light pollution. (Prepared from Starry Nights Pro screenshot.)

This  cluster has been known since ancient times since it is visible to the naked eye as a dim cloud (if your skies are dark and your eyes dark adapted) – Galileo was able to resolve it into about 40 stars with his small telescope and you should be able to do the same with ordinary binoculars. There are actually more than 200 stars in this cluster and according to the Hipparcos satellite, the cluster is 577 light years away.

This also makes a handy illustration of sky directions. Remember – in the sky directions are a bit  different from on the ground – west is the direction the stars appear to move each night and north is the direction towards the North Star.  In looking at the Beehive you will get a good sense of North and South because Asellus Borealis and Asellus Australis line up pretty much north/south as their names imply. What’s more,   Mars is moving eastward against the background of stars and it’s travel can be seen from night to night. It will take it little more than a week to pass in and out of our binocular field of view that is centered on the Beehive and by early November it will be close to Regulus, the bright star at the base of the Sickle of Leo.

Eastward journey of Mars from September 25 to October 3, 2011. Circle represents the typical field of view for low-powered binoculars. Click image for larger version. Prepared from Starry Nights Pro screenshot.

Jupiter – evening, midnight, or morning – take your pick!

And I should add, bring your binoculars, for using them to spot Jupiter’s moons will be the real focus of this post.

Jupiter is a magnificent, brilliant “star” that rises in the east shortly after sunset and will be dominant on any night this fall – nothing will outshine it but the Moon – and as we get closer to winter, Venus. In early October you’ll have to wait until about three hours after sunset for Jupiter to be well placed for viewing. By the end of the month it will be high enough in about two hours after sunset. Once up, it’s good for the rest of the night, so if you’re out viewing Mars in the early morning, for example, take in Jupiter as well.  But the fun increases expoentially when you observe Jupiter with binoculars, or any  small telescope. We’ll focus here on the binocular view because most people have binoculars.

Why are binoculars so important? Because of Jupiter’s four bright moons which constantly change positions with the changes noticeable over a matter of hours and certainly from night-to-night. These are the Galilean Moons – the ones the great scientist discovered in 1610 and with nothing more than binoculars you can follow in his footsteps, discovering them for yourself. And try to imagine the excitement it caused, for discovering these Moons helped change our whole view of the universe – they were solid evidence that not everything revolved around the Earth, as thought, for here were four objects obviously revolving around another planet.

Jupiter can be great fun – and a challenge – for anyone with binoculars.  It is common to say that bincoulars are all you need to see Jupiter’s four bright moons.  This is true  – but I’m afraid a bit misleading.  Don’t think you’re going to just pop out the door some night in October and glance up at Jupiter with the binoculars you bought for sports events and immediately see the moons. Those binoculars should do the trick, but it’s a bit more challenging than that for most of us. (OK, I’m 70 years old and in average health with reasonable eyesight – someone younger, healthier,and with sharper sight might find this easier.)

For example, one recent morning I was surprised by a few hours of clear skies. I grabbed three pair of binoculars and decided to put this idea of seeing Jupiter’s moons to a systematic test. I’d glimpsed them before with binocuars, but most of the time I look at Jupiter either with my naked eye, or a telescope.  With the naked eye you can’t see the moons – with a telescope you can’t miss them. So here’s what I learned in my little binocular test.

With binoculars in astronomy the goal is to gather more light and the bigger the objective, the more light it gathers and thus makes fainter objects brighter. The 40mm objectives are roughly the equivalent of 63 eyes, the 56mm objectives, 123 eyes, and 70mm objectives 192 eyes.

First, my equipment included an ordinary pair of birding/sports binoculars – 8X40 Celestrons – I had bought several years ago.  I also had a pair of my favorite “quick look” astromical binoculars, the very large 15X70 Celestrons, and a pair I had recently bought from Garrett Optical as an experimental compromise to these huge ones – 11X56 Gemini binoculars. The issues here are simple. The larger the objective glass, the more light is gathered and thus the brighter the moons should appear.  The objective glasses on my binoculars were 40mm (quite typical), 56mm (unusual) and 70mm (pretty common as inexpensive astronomical binoculars go.) The magnification rose in keeping with the objective lens size – 8X, 11X, and 15X – and the more magnification, the more separation between moon and bright planet, so the easier to see the moons.

Bigger objectives means bigger - and heavier - binoculars. From left, these are 15X70, 11X56, and 8X40.

This should quite obviously point to the 15X70s being the binoculars easiest to see Jupiter’s moons with – and I won’t keep you in suspence – they were.  But this also flies in the face of common advice given to persons choosing binoculars for astronomy – advice that up until a year ago I usually gave. And that is, you can’t hold these big binoculars steady – both because they are too large and heavy, and because they magnify too much.  And that’s true. What’s more, if you can’t hold them steady, you shouldn’t be able to see difficult things – and that’s not entirely true.

The standard wisdom is that 10X50 binoculars are the largest binoculars the typical person can hold steady and so are the best for handheld astronomy. It’s not bad advice. But it isn’t entirely true. It depends on exactly what you want to do with them. If you want to be able to wear them around your neck all night and frequently hold them to your eyes for long, thoughtful gazes at the Milky Way, I agree – go for the 10X50s. They won’t wear you out and they will give you a lot of good time with the stars.

But – if like me – you want to use them for an occasional look in the course of an evening – and if you want to be able to see fainter stars and even fainter nebulae, clusters, and galaxies, I recommend the 15X70s and I will even go so far as to recommend the Celestron 15X70 Sky Masters because I’ve had good luck with that brand and model and it usually can be had for between $50 and $80 and they are surprisingly good for the price – though I do urge you to get a better, padded strap to go with them. The one that comes with them is too dinky.  And treat them gently. Most binocular optics will get out of whack if they are dropped, or bounced around.

Here’s the sort of thing you are hoping to see:

How Jupiter's moon might appear at one specific moment - in this case a moment when they were all on the same side of the planet. Of course the next night the view could be quite different. The letters stand for Europa, Io, Ganymede, and Callisto.

And keep in mind this view will occupy only a small part of the center of your binocular field of view.

The largest circle represents the typical field of view with low power binoculars. The next circle shows the field with 15X70 binoculars - and the green circle represents the amount of space Jupiter and its moons will occupy in such a field of view - quite tiny, but Jupiter is so bright it will seem bigger.

So back to Jupiter. I had a clear sky with Jupiter well up in the west.  I stepped out onto my deck with all three pair of binoculars and tried to see Jupiter’s moons with first one and then the other. Nothing. I could not see a single Moon. Why? Two reasons.

First, my eyes were not dark adapted and the moons are a faint target. They look like stars and their magnitudes may fool you into thinking you can see them quite easily, for they are as bright as some of the faintest stars we see in areas where light pollution isn’t a big problem. But they are very near an incredibly bright object – Jupiter – which in October will be very close to magnitude -3 – only Venus, the Moon, and Sun are brighter!  Since the moons are generally within 10 arc minutes or less of the planet – think of that as about 10 planet diameters – they frequently get lost in the glare of Jupiter. And that brings us to the second issue – focusing the binoculars.

Binoculars need to be precisely focused for this task and that isn’t as simple as it sounds. First, a lot of people don’t know that it’s a two-step process to focus binoculars. With the typical center-focus binocular you need to look through the binocular, close your right eye, and focus with the center wheel. When the object is sharp in your left eye view, then close the left eye and now focus the right side using the diopter setting – that  means turning the knob that surrounds the eyepiece on the right. (This isn’t always obviously marked as such – just try turning the right eyepiece as you look through it.)  This brings both sides of the binocular into sharp focus and accounts for any difference between your eyes. Not difficult – but on a dazzling object such as Jupiter against a dark sky I had to do this repeatedly with each pair of binoculars before I was satisfield I had a really sharp view.

And this is where you will first notice how difficult it is to hold any binocular – but especially the larger ones – steady.  Focusing on a bird or quarterback or race horse is far easier. We usually don’t demand such precision out of what are – in all but the most expensive – quite crude optical instruments.  The stars put these inexpensive optics to the test.  So be patient. Do your best to get Jupiter to quiet down and sit still and be round.

And by the time you do – Voila! Bet your dark adaption will be pretty good. If it isn’t, give yourself 10-to-15 minutes in the dark  – no flashlights or other white light – to get your eyes properly adapted.

Now those two things out of the way I decided to do this the hard way. I knew the largest binoculars would give me the best view, so I didn’t want to prejudice things by looking first through them.  I wanted to pretend the smallest was all that I had.  So I looked first with the 8X40 glasses  and after about a minute of careful observing, a tiny dot of light popped into view on the west side of the planet.  Aha! A moon. Probably Ganymeade because it’s the largest and brightest.

That I saw while standing up.  I then went in and got a pillow, brought it out and lay down on the deck. This was better. I saw Ganymeade quite easily and the more I looked I saw there was a second moon closer to the planet – probably Europa or Io, but I couldn’t be sure – any of the moons can appear to be close – it’s just that Europa and Io never wander too far away from it, while Callisto can be quite far out – or in our line of sight, appear to be quite close.

I later brought out a comfortable deck chair and it proved to give me almost as good views as I got lying down – I could hold the binoculars steadier sitting than standing.

I should add here that I have good straps on all the binoculars and sometimes I push my elbows through the straps and spread them out to give me  a steadier grip. You can get quite fancy with this approach, using the strap in various ways much as soldiers and competitive shooters learn how to use a rifle sling to steady it.

There is a ton of excellent advice with pictures on how to hold binoculars steady here. And you can mount them on a camera tripod.  Many places sell an inexpensive adapter, such as this one,  that works with most binoculars.  The problem with this tripod approach is the higher things get the more awkward it is to look through the binoculars – so don’t wait too long. When Jupiter is about 30 degrees up – three fists above the horizon – would be a good time to give this tripod approach a try. More elaborate parallelogram mounts for binoculars are great fun, but can cost significantly more than the binoculars and sort of defeat the purpose of having a light weight, easy to carry and use observing tool.

But back to the handheld tests. I had certainly seen one moon and gotten hints of a second and the slightest whisper of a third. How did the 11X56 do? About the same. Except with the larger binoculars the  “hints” turned into certainty for the second moon and there was, from time to time, solid suggestions of a third moon out well beyond Ganymeade – which could only be  Callisto. This business of now-you-see-it, now-you-don’t is not unusual with faint astronomy objects. Our sky conditions rapidly change giving us clear, momentary looks at things that are on the edge of the capabilities of our eyes and instruments.

When I switched to the 15X70s all three moons were confirmed and really quite easy – yet I will remind you, before dark adaption and careful focusing, I wasn’t seeing any of the moons even with these larger binoculars.

And that was it. I did a lot more observing and retesting and being sure of my views through each binocular and the more I observed the easier it got – and the more just plain satisfying. Galileo would have loved any of these binoculars. Knowing exactly where to look and what to expect is a big help. The moons will always be pretty much in a line with the equator of the planet – but they can be on either side of it and one or more may be hidden from view at any given time and all might be quite close, or all on the same side. And the line holding the moons may tilt upward or be level, or tilt downward depending on the position of Jupiter in the sky. So while much of the universe is unchanging – at least on our time scale – this is one part that changes constantly.

If this is your first time looking for the moon, do yourself a favor. Go to this page at the Sky and Telescope Web site and open the JavaScipt utility.  It will tell you right where the moons are – and which is which – for any given moment. On the morning I looked, here’s what that utility showed me.

Screenshot of javascript utility at Sky and Telescope showing positions of Jupiter's bright moons.

Notice all four moons were on the same side, but one, Europa, was too close to the planet for me to see! So the bottom line is this. I saw all three moons with all three binoculars once my eyes were dark adapted and t e binoculars were well focused and I was sitting or lying to hold them steady.  But despite the difficulty of holding the binoculars steady, the biggest gave me the brightest and best view.

Ghostly light, meteors, and the Moon this month

The ghostly light I refer to is the zodaical light which is sometimes known as false dawn. In the fall it is best seen in September and October in the morning – and you must do it in an area that has dark skies – skies which reveal the Milky Way – and at a time when there is no competition from the Moon which would easily drown it out. For this fall that means you best bet is the first week or so of October. You need to pick your time carefully – between two hours and 80 minutes of sunrise. You look in the east and what you;re trying to spot is a wide, conical light rising fromt he eastern horizon.

If you go out looking for Mars in the early morning at the start of the month, be sure to include alook for Zodaical Light once your eyes are well dark adapted.  You’ll find more details about it near the bottom of this post.

On the meteor front I think the best bet this month is the Orionids which should be best on the morning of the October 22 – but don’t expect anything spectacular. The Moon will be a waning crescent and offer some interference and this “shower” is really just a drizzle. Other may put more emphasis on the Draconids because they are expected to be intense for a brief period on October 8th, but with the Moon nearly full that night it’s hard to imagine seeing anything but a few of the very brightest.

And speaking of the Moon, it is at first quarter on October 3, full on October 11, at last quarter on the 18th and new on the 26th. It will be quite close to Jupiter on the nights of October 12, 13, and 14, but even though near full, will not over power the brilliant planet. That is, jupiter will be easily visible, though stars in that vicinity will not.

On October 28th The Moon and inner planets will put on a challenging display in our western sky with Venus and Mercury. The Moon is  two days old and shouldn’t be too hard to  find. Venus is brilliant at magnitude -3.9 (a full magnitude brighter than Jupiter) and though very close to the horizon, should also be fairly easy with binoculars and clear skies. Mercury? Good luck. It’s around magnitude zero, so significantly dimmer than Venus, but brighter than the star Antares – but it is so close to the horizon you’ll have to have a completely unobstrcuted view and awfully good luck with clouds. I’d start looking about 10 minutes after sunset using binoculars. Our chart below is for half an hour after sunset. Much later than that and everything will be too low to see – or have set. Even at that time the Moon is just six degrees above the horizon- roughly half a fist!

Chart is for half an hour after sunset on October 28, 2011. Prepared from Starry Nights Pro screenshot.

Events July 2011 – Neptune celebrates Year One! Plus – let the Moon find stuff for you.

Can you imagine it? Neptune, the most distant full-sized planet, becomes One Neptunian Year Old on July 12! Should we sing happy birthday? Or Happy New Year?  Or how about just getting to know it a little better, then seeing if we can locate it with our binoculars?

Click for larger image. (Graphics courtesy of NASA - Neptune "facts" added by me. )

That’s right – Neptune was discovered on the night of  September 23/24, 1846.  That’s when it entered the awareness zone of the inhabitants of the third rock from the Sun.  And it has taken it all this time to make a single trip around Sol – almost 165 years.

So – your challenge this month will be to reprise the discovery of Neptune – but we won’t ask you to do the astounding math that led to its discovery in the first place.  What I really like, is when Neptune first was discovered, a graduate student working on the project exclaimed: “That star is not on the map!”

You bet – because that “star” is not a star, but a planet – a “wanderer.”  But when you look at it with your binoculars it will look pretty much like any other star – which is why it fooled some of the greatest observers, including Galileo.  In fact, even if you own a small telescope it will take very high power and steady seeing to see the disc of Neptune. Galileo recorded this “star” twice in 1613 even noting that it had moved – but he didn’t understand the significance of what he had seen. Of course, he had a lot of other things on his mind at the time and everyone assumed then that the Solar System ended with Saturn.  Who even dreamed there were two huge, exotic chunks of ice out there, Uranus and Neptune, yet to be discovered?

But first . . . we interrupt this program for this special message . . . !

I have to admit, Neptune is a challenge object, and if you’re just starting out with your exploration of the universe, why not let the Moon be your guide this month to some more modest finds? It can lead you to Mercury, Mars, one of our bright guide stars, Antares – and if you’re an early riser, even to the Pleiades! So if you feel finding Neptune is a bit much for you, then try using the Moon as a “guide star” to help you discover brighter objects you can see with the naked eye.  Jump to here for all the details.

 . . . and now back to our regularly scheduled program

OK – Neptune shines on the bright side of magnitude 8, which means it should be visible in ordinary binoculars under reasonably dark skies, although 50mm binoculars will give you a better chance, and my favorite  for this kind of a  project are a pair of inexpensive 15X70 Celestrons. I found it in a few minutes with 15X70 binoculars – with 7X35 binoculars it was just on the edge of visibility. If your skies are real dark, they would work, but I recommend at least 50mm binoculars for this project.  But whatever your binoculars, it’s important you know two things about them – their field of view, and how bright a magnitude 8 “star” such as Neptune will appear in them.

Field of view (fov) is fairly easy since on most binoculars it is written on them in degrees. If it isn’t you can make the assumption that if they are 7 power, then they probably have a fov of about 7 degrees. Ten power binoculars will have a smaller field, closer to 5 or 6 degrees, and the 15X ones I favor have a 4.5° fov.  I show a couple of different fields on the accompanying star charts so you can get an idea of how much sky you see when you use your binoculars.

Knowing how bright a magnitude 8 star should appear in your binoculars is a little tricky, but fortunately there is one fairly close to Neptune, and it will be a big help. Your binoculars, of course, gather much more light than your eye and thus you will see many more stars than you can see with your eyes alone.  Not only that, but stars you do see with the naked eye will appear brighter in the binoculars.

Start the search!

Yes, let’s get going. The Moon will offer the least interference in the first 13 days of the month.  If you don’t find Neptune by July 13, you may want to wait until the Moon is past last quarter – the final week of July.  This is an early morning project, since Neptune doesn’t rise until about three hours after sunset and  you really want it to be as high in the sky as it gets to make the search easiest.  Unfortunately, by the time Neptune is due south and at its highest point, morning twilight has already begun. So I suggest you fudge it and set your observational goal for a  2 – 3 am start time.

At that hour you want to look generally south – well, a tad east – into a sky that is really quite empty of bright  stars and clear guideposts.  The brightest star in the general vicinity is Fomalhaut, but there are two other reasonably bright stars nearby that can serve to  guide you. Take a careful look at this chart. What looks like a triangle drawn by a 2-year-old on the right is actually the relatively faint constellation Capricornus. In classic terms you can put these stars together to form a mythical creature known as the “Sea Goat” – half goat, half shark. Good luck. I see a big awkward triangle and the tail end – eastern most – has two third magnitude stars that are pretty easy to pick up, the brighter being named Deneb Algiedi.

Use this chart to make sure you have the general location of Neptune. Click for a larger version. Read more about it below. (Prepared from Starry Nights Pro screen shot. )

For a  orinter friendly version of this chart, click here.

A tale of two tails

Get your general bearings by identifying the  three brighter stars in view. Fomalhaut is a first magnitude guidepost star and will be about 16 degrees above the horizon while Neptune is more than twice that altitude. Deneb Kaitos (the Sea Monster’s tail) is magnitude 2 – the same brightness as the North Star, Polaris.  Deneb Algiedi (the Sea Goat’s tail) is a bit dimmer at magnitude 2.8, but more important to our search. Finally, the “Circlet” is in Pisces – yep we have a whale, or sea monster, some fish, and a “sea goat,” a very nautical section of sky. The “Circlet” consists of fourth and fifth magnitude stars in Pisces and if you can see these, count yourself as having good, dark skies.  But don’t expect the “Circlet”to jump out at you – these stars are as faint as most of the stars in the Little Dipper.

And now, Neptune!

A simple star hop takes you to Neptune - see explanation in text below. Click for larger image. (Prepared from Starry Nights Pro screen shot.)

For a printer-friendly version of the above chart, click here.

Using this chart – First, your binoculars may show more stars than these, but they will all be fainter than Neptune. The larger numbers, 1, 12, and 31, mark the position of Neptune on those dates in July 2011. Of course, you may spot it on a different date and thus at a slightly different position along an imaginary line connecting all the dates. The other numbers you see represent star magnitudes to one-tenth of a magnitude – only we don’t put a period in the number because it might be mistaken for a star. Thus “78,” for example, means magnitude 7.8.

Hop 1 –  Locate Deneb Algiedi and its slightly dimmer companion in your binoculars.

Hop 2 – Use this bright pair as a rough guide as you move to the left (eastward) with your binoculars and come to Magnitude 4.3 Iota Aquarii.  (You should be able to see this with your naked eye, as well.)

Hop 3 – Draw mental line between Iota and slightly brighter Theta Aquarii. It’s about 6.5 degrees away so you may not fit it in the same binocular field.  But Neptune lies right along that line.

Hop 4 – The 5.4 magnitude star about one third of the way along this line between Iota and Theta,  anchors a rectangle (as shown)  that includes stars of 7.4, 6.6, and 7.8 magnitude. That last star  – magnitude 7.8 – is especially interesting because that’s the exact magnitude of Neptune.  So on the first of July, for example, that star is on one side of the 5.4 star while Neptune is about the same distance away on the other side. It’s that 7.8 magnitude star that tells you how bright such a star should appear in your binoculars – very faint – and thus tells you what you should expect to see in terms of Neptune.

Of course, if you really want to be sure you have found the “wanderer” Neptune, then you need to make your own chart – you can do that from the one supplied – and mark on it where you believe Neptune is on at least two nights. Ideally they would be several days apart so you could detect the motion.

Planet hunting – at least hunting a faint, distant planet like Neptune –  is not easy.  Just taking up this little challenge should help you appreciate the task astronomers had 165 years ago.  But if you want to know more, I highly recommend you read the article in Sky and Telescope magazine for  July 2011. You can find the story told elsewhere on the Web – it involved  mathematical predictions from two different sources – but what i feel is the definitive article on the subject is in  this month’s S&T.

Let the Moon be your guide

Here’s a simple idea. Everyone can find the Moon when it’s in the sky, so why not take advantage of its travels and use it to point the way to bright stars and planets?

OK? Let’s do that! As the Moon changes location and size during the month, I’ll point out some key items in its neighborhood.  You, of course, have to look on the date specified,  And here are a couple of quibbles:

1. As the Moon gets closer to being full it’s glare will tend to drown out all but the brightest stars near it. Sometimes you may even need binoculars to see some stars that are near.

2. My charts are precise only for my latitude and longitude – roughly 42° N latitude and 71° west longitude – the East Coast of America. If you are on the West Coast the Moon will have moved a bit eastward, for example,  (It moves at the rate of half a degree an hour – that means it changes position by the size of its own diameter every hour.  This should not matter much. Just use the charts as a general guide if you live in  North Amerca.  Elsewhere in the world the difference could be significant – as much as about 12 degrees,

That said – here are the key dates to look for the Moon – and the objects expected near it, for July 2011.  Pick a date and give it a try. Even if you know the object, it could help you develop a better feel for the night sky.

July 2 and 3  – Locate  Mercury

Always hard to find because it is frequently lost in twilight when visible, Mercury makes a good appearance this month in the western evening sky. Start looking about 30 minutes after sunset.  You may also pick up Castor and Pollux, but they will be fainter than Mercury. And finding any of these objects requires an unobstructed western horizon and clear skies. Binoculars are extremely helpful as well.

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

July 4 – passing Regulus

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

July 7 – first quarter Moon with Saturn, Spica, and the “Sail”

I love this grouping. It will help you find Saturn, always a delight in any size telescope, as well as identify another bright “guidepost” star, Spica. Finally, though you’ll probably need binoculars to pull it out of the Moon’s glare, the “Sail” is a favorite asterism, for it looks like the sail on the old, gaff-rigged Beetle Catboat I spent so many wonderful summer days sailing.  These stars are more formerly  a major part of the constellation Corvus.

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

July 11 – to the Heart of the Scorpion!

Here’s a constellation I love with a bright, red guidepost star, Antares.  And here’s the moon – getting near full and passing very close to Antares which is at the heart of Scorpius. Try using binoculars if you don’t see this bright star at first – you should be able to pick it up with it’s two companion.  But the Moon will certainly do its best to drown it out.

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

Time to switch to the morning sky! July 24 – the Moon and Jupiter.

Click for a larger image. ( Prepared from Starry Nights Pro screen shot.)

July 25 – the Moon and the Pleiades

Click for larger image. (Prepared from Starry Night Pro screen shot.)

July 26, 2011 – Crescent Moon, the Hyades, and Aldebaran

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

July 27, 2011 – Could that be Mars? you bet!

The small, red planet is barely first magnitude. But since it is within about three degrees of the Moon you should be able to fit them both in the same binocular field of view about two hours before sunrise when they are roughly 10 degrees – one fist – above  the eastern horizon.

Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

Events for June 2011: Saturn and Porrima, Morning planets, and a total lunar eclipse for the rest of the world

Let’s start with that total lunar eclipse June 15 – it totally misses North America. But it should be quite a sight in much of the world. Take a look at this map. If you’re in the white area – or even the grey – then go to this site for more information. Otherwise – well, it still is an interesting month with Saturn running up to steal a kiss from Porrima, the morning planets continuing their show, and Mercury peeking above the western horizon late in the month.

First, here’s the lunar eclipse map.

Are you in the dark? Then you miss the eclipse. But much of the world should see all - or some phase of it this month.

Saturn and Porrima

Saturn and the beautiful double star Porrima – you need a telescope to see it as double –  continue the dance they started in May. Here’s a simulation over the  two months, prepared with Starry Nights Pro software.

Saturn is easy enough to find. Wait until an hour and a half after sunset, then look for it high in the south-southwest about 15 degrees from Spica. (Saturn will be just a tad brighter and should look yellow compared to Spica’s blue.) For the naked eye observer, watching Saturn and Porrima during June of 2011 provides a terrific opportunity to see a planet in retrograde motion – then pause,  then swing back in its normal eastward path against the background stars.  For the small telescope user it’s even better.  Porrima is a stunning double star when seen in a back-yard telescope – and Saturn, with its rings, the most awesome planet in a small telescope. During early June the pair come amazingly close – so close they’ll both fit in the same telescopic field of view in the first part of the month.  Here’s where to find them and how they will look during the first week of the month.

Click image for much larger version. Insert shows how Staurn and Porrima will look in a small telescope with a one-degree field of view. To split Porrima you will probably need a telescope with at least an 80mm objective and use 180X or more. The two will start drawing apart after about 10 days, but will still be very close at the end of the month.

You can read all about Porrima and how to split it in my friend John Nanson’s post on the star-splitting blog we share. Check it out here!

Summer Solstice and Mars

Much of the planet show is in the morning sky, as described last month. There you will find Jupiter with its retinue of four Gallilean Moons rising a bit earlier each day.  Uranus and Neptune are in the same genral vicinity, only higher. Mercury abandons the morning sky and puts in  a difficult ( for northern hemisphere observers) appearance in the evening sky near the end of the month. Mars is a bit more fun. At the start of the month it is already well past Venus and on a course that eventually takes it reasonably close to the Pleiades. As the chart shows, you should be able to fit both in the same binocular field of view by the time of the Summer Solstice.

Click image for a much larger view. (Prepared from Starry nights Pro screen shot.)

Near the end of the month (June 28, 29) the waning crescent Moon will join Mars and the Pleiades in the eastern morning sky.

Meanwhile, in the west . . .

In the last three or four days of the month you may catch Mercury, about half an hour after Sunset, moving up to join Castor and Pollux. Binoculars may be needed since they are all low and the twilight will be bright – but check it out. On the 30th they are all in a row and you can nearly cover all three  by making a fist and extending your arm.  They are all pretty close to the same brightness as well.

Click image for a larger version. (Prepared from Starry Nights Pro screen shot.)

Events: The planets in May 2011: Everyone’s at the party!

May offers a planet spectacular in three parts – first, the evening show where Saturn  meets the stunning double star, Porrima; then the full morning show where the rest of the the planets gather, and then the pre-dawn special, which Sky and Telescope magazine calls “the most compact visible gathering of four bright planets in decades.” Here’s a summary in pictures of each of these events with links at the end of each summary for more details and many more charts

Saturn Kisses Porrima

Here’s a simulation of Saturn’s dance with Porrima over the next two months, prepared with Starry Nights Pro software.

For the naked eye observer, watching Saturn and Porrima during May and June of 2011 provides a terrific opportunity to see a planet in retrograde motion – then pause,  then swing back in its normal eastward path against the background stars.  For the small telescope user it’s even better.  Porrima is a stunning double star when seen in a back-yard telescope – and Saturn, with its rings, the most awesome planet in a small telescope. During May and June of 2011 the pair come amazingly close – so close they’ll both fit in the same telescopic field of view near the end of May and in early June. For more details, go here.

The Full Morning Show

This shows you where six of the seven visible planets are in the eastern pre-dawn sky about 30 minutes before sunrise - however, to find Neptune and Uranus you'll have to look earlier when the sky is darker. And please - click this image for a larger view! (Prepared from Starry Nights Pro screen shot.)

Frankly, Neptune and Uranus will be easier to see later this year, but if you’re getting up early to see the pre-dawn gathering of four planets very close to one another, then why not get up a couple of hours earlier and do a search for the outer two planets, Uranus and Neptune? You’ll need binoculars, an unobstructed eastern horizon, and clear skies, of course. For more details, go here.

The Pre-dawn Special Show

Jupiter, Venus, Mercury, and Mars, as seen in the predawn sky of May 11 from mid-northern latitudes. I've modified this Starry Nights Pro screen shot to include images of the planets to scale - a reminder of what these faint morning "stars" actually look like up close and personal. Click image for a much larger version.

As mentioned, May’s pre-dawn skies brings us what Sky and Telescope calls “the most compact visible gathering of four bright planets in decades.” And it goes on most of the month! The best seats in the house for this show will be to the south – the farther south the better. Those of us in mid-northern latitudes will find it more challenging to see this  pre-dawn show, and for all an unobstructed eastern horizon and exceptionally clear weather is a must. If I’m hoping for one morning of exceptionally clear skies it would be for May 11 – but fortunately the show starts well before then and continues well after that date. Go here for more details and many more charts.

Saturn Kisses Porrima – the details!

The outer planets generally appear to move eastward against the backdrop of distant stars. However, as Earth overtakes a planet in its orbit and passes it, the planet appears to move backwards – westward – called retrograde motion.  Watch Saturn during May and June to see this change in reverse, for in this case during May Saturn is already in retrograde (westward) motion. Then in the first two weeks of June it appears to halt, stand still, then reverse itself to resume  eastward motion.  Though Saturn’s motion is very slow – it takes 29.5 of our years to complete a trip around the Sun – its motion is easy to mark this year as you note its changing relationship to the bright (magnitude 3.4) star Porrima.  This you can do with the naked eye, but the changes will be easier to see if you use binoculars and make a little chart.  At the start of May Saturn is about 1.5° from Porrima. By the end of the month it’s separated  from Porrima by less than 20 minutes of arc – about one third of a degree. During the first few days in June it will appear to stand still, then will slowly resume its eastward motion, putting more and more distance between it and Porrima. To observe all this, start with this chart, use your binoculars, and note its changing position. (You don’t have to start on May 1 – any day this month will do – but it will be good if you can check every week or so and draw in the changing position of Saturn. )

Here are Saturn and Porrima at the start of the month. Saturn is the brightest "star" at magnitude 0.54 and Porrima the next brightest at Magnitude 3.4. There are a couple of other stars in the field that are magnitude 6 and the rest should be visible in binoculars if you look carefully. Note: Porrima is always to the west of Saturn - but early in the evening it will feel more like it is "above" Saturn. Remember - west is the direction everything appears to move as the night goes on. Click image for a larger version. (Prepared from Starry Night Pro screen shot.)

To keep track of Saturn’s changing position night-to-night and see it  switch directions,  download this “printer friendly” version of the above chart.

For observers with telescopes this should make a stunning sight – especially during the first week of June. The trick will be to use an eyepiece that gives you enough magnification to split the very close pair of stars that is Porrima, yet include Saturn in the same field of view.  I’m planning to use a 4-inch refractor and a wide-field eyepiece delivering at least 150X. I’m honestly not sure if that will be enough – depends on conditions.  On April 29 I could fit the pair comfortably in a low power (22.5X) field. I could not get a clean split of Porrima at any power because the air was too turbulent. In theory I should be able to see both Saturn and a clean split of Porrima near the end of the month or in early June, but the weather will have to cooperate!  Not being sure if it will work is all part of the fun. You can read all about Porrima and how to split it in my friend John Nanson’s post on the star-splitting blog we share. Check it out here!

Incredibly, Porrima was apparently named for two sisters who were goddesses of prophesy. Since the name was given before they could possibly tell that Porrima was two stars, that’s sure some prophesy! If that’s the case, I’m sure we can assume Saturn – the Roman god of agriculture – is playing the shy farm boy,  giving them both a kiss,  then running. 😉

The Full Morning Show – in detail!

Finding Uranus and Neptune requires an early start in May, but with patience, both can be located using binoculars, though Neptune is a challenge because of its dimness and  Uranus because it’s still close to the horizon when it is dark enough to see. Let’s start with Uranus.

Finding Uranus - First see if you can locate the Circlet of Pisces about one fist above the eastern horizon and consisting of 4th and 5th magnitude stars. Binoculars will probably be needed for this. Click chart for larger view. Prepared from Starry Nights Pro screen shot.

Step 1 – The challenge in finding Uranus is you need a dark sky – but the planet is just getting high enough to view as astronomical twilight – the first hint of dawn – begins. So you might start looking for the circlet of Pisces about two hours before sunrise and after you locate it, look closer to the horizon for Uranus.  The Circlet consists of five stars that are about as bright as the four fainter stars in the Little Dipper. There are two others included in our chart and these are even fainter. The whole asterism may be just a little too large to fit in your binoculars. Here’s a printer friendly version of this first chart.

Step 2: The circle covers five degrees - about what you see in binoculars. Notice the distinctive trapezoid asterism to the left? That should serve as a good guide. Uranus will be just slightly brighter than the stars of this trapezoid. Click image for larger view. (Prepared from Starry Nights Pro screen shot.)

Step 2 – Between the Circlet of Pisces and the eastern horizon you should find Uranus about an hour before sunrise – but start looking a bit earlier. The sky will be getting brighter making it difficult to spot this magnitude 6 planet, even with binoculars.  Here’s a printer-friendly version of the above chart.

Finding Neptune

Finding Neptune is easier because it’s higher than Uranus while the sky is still fully dark. But at magnitude 7.9 it is significantly fainter and as far as I’m concerned it’s in a celestial wilderness where the constellations are not much help and there is little in the way of bright asterisms to point the way. But for those who enjoy a challenge, here are a couple of charts. The first is a broad overview and gives you an idea of the general territory. For me the most recognizable feature is the Great Square of Pegasus, but that’s pretty far away. Closer – but fainter – will be the Circlet of Pisces included on the Uranus chart.

This chart will just give you an idea of the general region in which to search for Neptune on May mornings about two hours before sunrise. Click image for much larger - and readable - version. (Prepared from a Starry Nights Pro screen shot.)

This is Neptune at mid-month. It is moving from right to left, but very slowly, so the chart is good for the month, just understand the position may not be exactly what you see here. Click image for larger version. (Prepared from Starry Nights Pro screen shot.)

Download a printer-friendly version of this chart.

Guide to the early morning planet show – in detail!

OK, it’s worth repeating – Sky and Telescope magazine calls this “the most compact visible gathering of four bright planets in decades.”  The farther south you go, the easier this show will be to see, but the general rules apply to all locations.

Where you are and when you look is important!

The further south you are the higher the planets will be at any given instant and the higher they are the earlier you can look. The earlier you look, the darker the sky background, making the planets easier to find.

Binoculars are a critical aid.

Nothing special is needed – any binoculars will help – but when trying to see the fainter of these planets – Mercury and Mars – binoculars are absolutely critical in northern latitudes and will help no matter where you are. DO STOP USING THEM 15 MINUTES BEFORE SUNRISE, HOWEVER. YOU DON’T WANT TO CHANCE LOOKING AT THE SUN WITH YOUR BINOCULARS. THAT IS DANGEROUS.  And if you haven’t seen the planets by 15 minutes before sunrise, you’re not going to see them – so just sit back and enjoy the dawn!

An unobstructed eastern horizon and clear skies are essential.

Your fist held at arm’s length covers about 10 degrees. In mid-northern latitudes the planets will not get above 10 degrees before it gets too light to see them.

Start looking early.

The charts that follow are for a time that strikes a balance between the altitude of the planets and the darkness of the background sky. But if a chart is for 30 minutes before sunrise, start looking at least 15 minutes prior to that – perhaps half an hour earlier. The planets will be lower then, of course, but in events such as these you are playing a game with the elements – the higher the planet, the easier to see – but as the planets gets higher, the sky background gets lighter and the lighter the sky background, the harder it will be to see the planets – so the right hand gives while the left hand taketh away!

How to know which is which.

The planets will change position each day, and as you will see from the charts below, the arrangement varies depending on where you are as well. So how do you know which is which?  Brightness will be your key. The brightest is Venus, the next brightest Jupiter, the next Mercury, and the dimmest Mars.  Mars will be the most difficult as it is both dim and low.

To get a feel for what a difference location makes, look at the next three charts. Note the latitudes – the first is for 42°N, the next for 26°N, and the last for 34° S. Also note that the first two are for 30 minutes before sunrise, while the last one is for an hour before sunrise.

30 minutes before sunrise – 42°N

Circle represents a 5-degree field of view. Most binoculars will show a bit more. Click image for larger view. Prepared from Starry Nights Pro screen shot.

Click here to download a printer-friendly version of this chart.

 30 minutes before sunrise – 26° N

Click here to download a printer-friendly version of this chart.One hour before sunrise - 34° SouthHere's the view from Sydney, Australia - note change in time and date. Circle represents a 5-degree field of view. Click image for a larger view. (Prepared from Starry Nights Pro software.)

Click here to download printer-friendly version of this chart.

Changing with date

These four  planets will provide an interesting, but challenging, tableau most of the month as the visual relationships change. Here’s a guide to those changes using charts  for every four days – all are for mid-northern latitudes and for about half an hour before sunrise.  No larger versions are provided, so don’t bother clicking on them and all are prepared from Starry Nights Pro screen shots.

Things to notice in the charts:

  • First Jupiter joins Venus and Mercury, then as it moves on, Venus, Mercury, and Mars form a trio.
  • Mercury never puts in a good appearance this month and it gets more difficult to see near the end of the month.
  • Jupiter does just the opposite, getting easier to see earlier in the morning as the month goes on.
  • On May 1 a slither of the waning crescent Moon is in the picture.
  • On May 29 the waning crescent Moon re-enters the tableau and will be present the rest of the month, though quite challenging on the last day. (The amount of Moon that is lit and its exact location will vary with your location.)

Notice the waning crescent Moon has entered the picture? It will be here three days, the last near Mercury.

Planet summary for May

Mercury – It is visible all month, but so close to the Sun and horizon you’ll need binoculars to spot it.

Venus – How can you miss it at magnitude -3.4?  Easy. It too is getting close to the Sun.  But look at the right time and you’ll see it and with the naked eye.

Mars – Very tiny and very dim right now because it’s about as far away from Earth as it can get and also is challenged by the pre-dawn twilight. But at least Jupiter will be of help early in the month in finding Mars.

Jupiter – Assuming you can find it, will guide you to Mars because Jupiter, though visible only during twilight, is comparatively bright.

Saturn – You can’t miss it – it’s the one planet high in the southeast and south in the evening – not morning – sky.  It is still visible in the west in the early morning hours. It sets as the pre-dawn planet show begins.

Uranus – A real challenge for binocular users.

Neptune – Even more of a challenge and as with Uranus binoculars are an absolute must.

Pluto -Hey, I mention it because it’s there – but this takes a fairly large telescope, a good chart, and a lot of patience. Since this post is aimed primarily at those using the naked eye and binoculars, I won’t mention it again – just kind of fun to know it’s out there with the rest of the gang in the pre-dawn sky even if its status has been demoted to dwarf planet.

Building MESSENGER – the Model

NASA provides a neat little model you can make of the MESSENGER spacecraft by simply printing out the directions and doing a little cutting and folding. You can download it here. And if you have the energy and time, you can build a more sophisticated version by downloading this.

If all goes well, MESSENGER will become the first spacecraft ever to go in orbit about the planet Mercury. It will do so on March 17, 2011.  You can read all about MESSENGER – and how to see Mercury yourself  in March of 2011 –  by going to our March “Events” post.

Here are step-by-step photos of building the first – and simpler – of the two  MESSENGER models.  We’ve added a simple way to effectively display your work.


  • scissors
  • paper glue (we used rubber cement)
  • model knife (optional)


  • 4 sheets of paper – we used  24lb
  • a couple coffee storrers,  pipe cleaners, or something similar (most straws are too big around)
  • short length of  black thread
  • small piece of clear tape
  • paper clip

Building time is about 30-40 minutes.)


1. Assuming you have printed out the sheets, cut out the spacecraft body. (Click on any image to view a larger version.)

2. Cut out the three white circles (indicated by arrows) on the spacecraft body. I found a model knife was best for this. (You can actually do this as the first step – but in any event do it before folding.)

3. Fold along white lines to make the box-like body.

4. Put fast-drying glue on the edges of the folds.

5. Finish spacecraft body and set aside to dry.  Cut out the gold spacecraft sunshade.

6. Fold and  glue sunshade together with color side out.

7. Cut out the strip labeled “bridge,” fold lengthwise, and glue together, color side out.  Set aside to dry.

8. Cut out solar panels.

9. Fold, but do not glue together until you have noted the position the boom (coffee stirrer) will be inserted, This is marked by dotted lines on the dark side of the solar panels.

10. Put glue onthe inside being careful to leave the area marked by the dotted lines free of glue. (A tad tricky, since the lines are on  he other side.)

11.Fold the bridge along the dotted lines and glue one side of it to the spacecraft body in rectangle outlined on it.

12. Put glue on the taps of the bridge, then glue the sunshade to it. Set aside to dry.

13. We found that it was difficult to simply stick the boom into the slots left for them in the solar panels, but these slots were easy to open with any sharp object,. We used a toothpick to do the job.

14. We mounted one solar panel tot he boom,t hen slid the boom through the wholes in the spacecraft body.  We did not glue the solar panels as they seemed to fit tightly enough.

15. Here’s the almost finished spacecraft before  folding the sunshade to give it an arched shape and adding the thread and paper-clip hook to display it. Note the solar panels and gold side of the sunshade are pointed in the same direction – which would be towards the Sun with the instruments aimed at Mercury.

16. Ooops – alomost forgot the boom. Didn’t have a straw, or stirrer as recommended, so we used a pipe cleaner, cut down to size. We also folded the sunshade into a gentle arch that looks more like the pictures of the craft.  However, we found it awkward to display  the spacecraft properly by just sitting it down on something.  So we added a piece of black thread to the top, center edge of the sunshade with clear tape. On the other end I tied a paperclip , bent into a hook to make an easy hanger.  Here’s the thread taped to the sunshade.

17. And here’s the finished model, dangling under the lamp over the dining room table – a fitting. space age centerpiece for March, 2011! Hey – it’s a space craft. It’s not supposed to sit on the table. it’s supposed to be out there flying.

Looking at this  little modest model gives me pause . I try to develop a sense – in myself and in my visitors to Driftway Observatory – of the incredible emptiness of space by having one person hold a soccer ball representing our Sun while another visitor holds a 2mm glass bead representing our Earth.  On this scale Mercury would be less than 1mm in diameter – barely visible even when in your hand.  But I ask the person with the bead to hold it at what they think is the correct distance from the Sun. Usually they guess this to be a foot or two away – sometimes boldly they move several feet away. But no one guesses the correct answer, which is about 75 feet away. Now think of that. A 2mm bead – Earth – out at 75 feet from our soccer ball Sun!   Another 2mm bead – Venus – would be placed at about 54 feet out from the Sun.  And then a third, tiny Mercury – at roughly 29 feet.

And now try to imagine how tiny the real MESSENGER  spacecraft – roughly the size of a table – would have to be made to fit into this scale model! Then close your eyes picture the MESSENGER entering this vast, empty interplanetary ocean  and traveling for seven years in that emptiness, then arriving at just the right spot and just the right time, to be placed in orbit.  This vital little craft with its complex instruments going all that distance – almost 5 billion miles in total at speeds that sometimes exceeded 140,000 miles an hour.  (To put that in perspective, the fastest rifle bullet goes about 2,700 miles an hour and our Apollo astronauts traveled about 25,000 miles an hour during part of their lunar journey.

And all around Messenger is just about nothing except for a hostile emptiness and the incredible heat of our Sun as it moves in close.  Awesome! Just plain awesome. Three cheers for little MESSENGER – and three cheers for us – a species that dares to challenge the hsotile vastness of space, and send it’s robot silicon  and ceramic envoys on a mission of exploration for new knowledge.

Events: March 2011 – a special month for messages from Mercury, and it’s about time!

Mercury: As Seen from Our Backyards – and from Orbit

We don’t get a good look at Mercury often – and neither does NASA. But that all changes – for us and for NASA – this month.

Why don’t we get a good look at Mercury? Because this smallest of planets is just too darned close to the Sun, so it seldom gets high above the horizon, and when it shows up at all, it’s usually in twilight. Actually, in any given year we always have several chances to see it as one month it peeks above the eastern horizon just before dawn, then a couple of months later it gives us another opportunity when it is just above the western horizon right after sunset. March will be the best – and most convenient – chance for us to see it this year. In fact, we have the unusual situation of Jupiter pointing the way!


NASA hasn’t been to Mercury for 37 years! (The only NASA spacecraft to visit Mercury was Mariner 10 in 1974 and 1975.) In these days of space probes and planet landers, that’s a real long time between visits. But this month the MESSENGER spacecraft – which swooped in for a close look at Mercury while passing it in 2008 and 2009, hopes to complete its mission by becoming the first spacecraft to go into orbit around Mercury. NASA hopes it will be sending images and scientific data from orbit for the next year. Orbit insertion – after a flight of nearly seven years and nearly five billion miles – comes in mid-March just as we’re getting our best chance to see the elusive planet with our naked eye.

More details on the NASA mission in a moment, including a neat little spacecraft model you can build, but first let’s look at what we can see with our naked eye or when aided by ordinary binoculars.


Finding Mercury: Timing is everything

Lots of sky watchers never see Mercury, but it’s actually quite easy to see. You just have to look in the right place at the right time. And this year in March brilliant Jupiter is going to make it extra easy because Mercury stages a Jupiter flyby in the middle of the month. (Though Mercury and Jupiter will appear close together no matter where on Earth you’re seeing them from, this is generally a Northern Hemisphere event. The farther south you go, the earlier they set, and for much of the Southern Hemisphere they are either too near the horizon or already set by the time the sun sets.)

So here is when and where to get a good look at Mercury:

  • Of course you first need an unobstructed western horizon and very clear skies.
  • The charts are for about 30 minutes after sunset as seen from mid-northern latitudes – but generally good for anywhere in the Northern Hemisphere.
  • Each chart has a line on it indicating 10 degrees above the horizon – 10 degrees is what is covered by your first when held at arm’s length.
  • If you can find Jupiter, the brightest “star” low in the west, then you should have no trouble finding Mercury, which will be significantly dimmer, but still bright.
  • Binoculars will help, and the charts show a typical binocular field of view with Jupiter centered. (Caution: Be sure to wait until about 10 minutes after sunset before pointing binoculars in that general direction. Seeing the Sun with binoculars will damage your eyes!)
  • Pick a date from the charts below, click on the chart for a larger version, and plan to observe starting about 20 minutes after sunset and looking due west.
  • You may spot Mercury before and after these dates – these are just the easiest times because of the proximity to Jupiter.

March 11, 2011

March 12, 2011

March 13, 2011

March 14, 2011

March 15, 2011

March 16, 2011

March 17, 2011

March 18, 2011

March 19, 2011

March 20, 2011

March 21, 2011

Since ancient times Mercury has been known as “fleeting” and for good reason – it just doesn’t stay in one place for long, so look fast, because it will soon be gone again. This makes perfect sense when you consider that Mercury is the closest planet to the Sun and thus has the shortest orbit. It’s 88-day orbit means it goes around the Sun nearly four times while we’re making one trip. It is traveling at more than 107,000 miles an hour, while we’re poking along at just 66,000 miles an hour.

This shows the positions of Mercury and Earth on March 11, 2011. (Prepared from Solar System Live Orrey available on Web.)

I think of Mercury as something of a jokester. Because it is so close to the Sun, it’s always going to be near the Sun in our sky. That means it’s frequently drowned out by the light of the Sun. Even when it’s shining quite brightly, it may be doing so in bright twilight and thus be difficult to see. For example, as it gets higher in our sky this month, it should be easier to see because we’re looking through less atmosphere, and, of course, it’s farther away from the Sun so the background sky is darker. But, as it gets higher it’s also moving to a position more between us and the Sun and thus from our perspective we see less and less of the lit portion until it eventually becomes a crescent – so it actually gets dimmer. It is brightest at the start of the month and is a still a brilliant -1.3 on March 11. To put that in perspective, Sirius, the brightest star in our sky, is -1.5. But when Mercury is that bright it also is relatively low and thus in more twilight. In just 10 days it drops almost a full magnitude, to -0.5 – but it’s higher, so I suspect it’s likely to seem almost as bright. By the end of the month, though, it is magnitude 1.7 and has dropped to about 7 degrees above the horizon 30 minutes after sunset. Given the right conditions, this will make a nice target in a small telescope because it will show as a tiny crescent – but it will be much harder to find because of the twilight and dimness of the planet.


Meanwhile, Back at NASA, MESSENGER Is on an Historical Mission

None of this matters much to the folks at NASA. Their biggest challenge comes on March 17, 2011. They have high hopes, of course, but this is a complex mission, and while it has already returned significant images and new information, orbiting Mercury is the goal. Here’s how NASA put it in a recent press release.

“Although we feel that the preparations to date – and those scheduled for the next month – have been well thought-out, that the decisions made to define the specific activities were sound, and that the level of review and rehearsal has been more than adequate, we recognize the extraordinary complexity and unique nature of this endeavor,” says APL’s Peter Bedini, MESSENGER’s project manager. “But at this point, four weeks out, we are well positioned for success. The spacecraft is healthy, continues to operate nominally, and is on course to be at the right place at the right time at 8:45 P.M. ET on the evening of March 17.”

Of course they’ve had to solve tons of problems all along the way, not the least of which was how to protect delicate scientific instruments from the incredible heat generated by being so close to the Sun. The Sun is up to 11 times brighter at Mercury than here on Earth, and Mercury’s surface temperatures can reach about 840 degrees Fahrenheit. So the key to keeping MESSENGER cool (around average room temperature), is to have it carry its own beach umbrella – a sun shade made of heat-resistant ceramic cloth.

I remain in awe that the scientists and engineers can pull off a mission of this complexity. MESSENGER was launched August 3, 2004. It has reached speeds in excess of 140,000 miles an hour. (The Space Shuttle pokes along at 18,000 miles an hour when in orbit, and the fastest military jet is far slower than a Shuttle.) The straight line distance between Earth and Mercury can be as little as 60 million miles – yet the MESSENGER odyssey has taken it around the Sun and past Earth in 2005, past Venus in 2006 for a close flyby and a second Venus flyby in 2007, followed by Mercury flybys in January and October of 2008 and another in September of 2009. These close approaches to the planets can cause the spacecraft to speed up or slow down – and, in fact, it is the slowing down that has been part of the reason for the recent flybys of Mercury. In the 2009 event the speed of the spacecraft was cut from 12,000 mph to 6,000 mph and that was a critical to putting it into position for going into orbit. (I found this animation of the entire mission a bit hard to follow – I had to pause it at several stages – but that is simply because the mission is indeed lengthy and complex.)

An image from a Mercury flyby in January 2008 showing portions of the planet never imaged before. (Click for a much larger version.)

MESSENGER will still need its on-board rocket motors for the final maneuvers and, in fact, will use most of its stored fuel for this last effort. Here’s how NASA describes its plans for the night of March 17:

At 8:45 p.m. EDT, MESSENGER — having pointed its largest thruster very close to the direction of travel — will fire that thruster for nearly 14 minutes, with other thrusters firing for an additional minute, slowing the spacecraft by 862 meters per second (1,929 miles per hour) and consuming 31% of the propellant that the spacecraft carried at launch. Less than 9.5% of the usable propellant at the start of the mission will remain after completing the orbit insertion maneuver, but the spacecraft will still have plenty of propellant for future orbit correction maneuvers.
The orbit insertion will place the spacecraft into an initial orbit about Mercury that has a 200 kilometer (124 mile) minimum altitude and a period of 12 hours. At the time of orbit insertion, MESSENGER will be 46.14 million kilometers (28.67 million miles) from the Sun and 155.06 million kilometers (96.35 million miles) from Earth.

There’s a wonderful animation of the orbit insertion here, but this is a large file, so you need patience for the full movie to download.

NASA artist conception of MESSENGER spacecraft. All the alphabet soup refers to different instrument packages.

MESSENGER is a far cry from the Buck Roger’s style space ships we used to see in the movies and comic books. It’s a boxy little craft with instrument packages stuck on here and there and two wing-like solar panels for battery power, plus the sun shield. All of this in a squat box measuring roughly the size of a desk – about four feet by four and a half feet, by six feet. The thermal shade is about four feet by eight feet and semi-cylindrical. It weighs in at about 2,300 pounds and more than half of that is fuel.

NASA provides a neat little model you can make of MESSENGER by simply printing out the directions and doing a little cutting and folding. You will find complete step-by-step photos with download links to the model here.

What can we learn?

As the mission began, NASA outlined its goals. Some of these have already been achieved to one degree or another in the Mercury flyby by MESSENGER. But all can benefit from more exploration.The flyby gave a quick look – and an opportunity to image most of the planet. But being on station for a year is much different than taking a snapshot. Still, here are the basic scientific objectives as NASA outlined them:

Mercury’s density implies that a metal-rich core occupies at least 60% of the planet’s mass, a figure twice as great as for Earth. MESSENGER will acquire compositional and mineralogical information to distinguish among the current theories for why Mercury is so dense.

Before the MESSENGER mission, only 45% of the surface of Mercury had been photographed by a spacecraft! Using its full suite of instruments, MESSENGER will investigate the geologic history of Mercury in great detail, including the portions of the planet never seen by Mariner 10.

Mercury has a global internal magnetic field, as does Earth, but Mars and Venus do not. By characterizing Mercury’s magnetic field, MESSENGER will help answer the question of why the inner planets differ in their magnetic histories.

Through a combination of measurements of Mercury’s gravity field and observations by the laser altimeter, MESSENGER will determine the size of Mercury’s core and verify that Mercury’s outer core is molten.

At Mercury’s poles, some crater interiors have permanently shadowed areas that contain highly reflective material at radar wavelengths. Could this material be ice, even though Mercury is the closest planet to the Sun? MESSENGER will find out.

MESSENGER will measure the composition of Mercury’s thin exosphere, providing insights into the processes that are responsible for its existence.

Undoubtedly, there will be surprises. In fact, there already have been. For example, in the flybys, what looks like ice was discovered on parts of the planet. Keeping in mind that typical temperatures on Mercury would make a pizza oven seem comfortably warm, that’s astounding. Here’s NASA’s take on the ice:

So how is it that the planet closest to the Sun has temperatures that possibly can sustain ice? Simply, Mercury’s axis of rotation is such that sections of the planet, the deep floors and walls of craters near its poles, are always shaded. In these frigid areas of Mercury, temperatures can dip to minus 350 degrees Fahrenheit. Radar pictures from Earth show material in the craters that resembles ice, but its identity is one of Mercury’s mysteries that NASA hopes to solve.

Now this is not a place I want to spend my next vacation! I mean 840 degrees in the Sun and -350 degrees in the shade! Sure helps put our seasons into perspective – and MESSENGER gives us a lot to ponder as we watch this beautiful little “evening star” climb up our western sky and pass mighty Jupiter this month. The ancients marveled at Mercury, their “messenger of the gods.” But the more we learn about it through our modern MESSENGER, the more awesome it becomes.


Spring Equinox and Zodiacal Light

Don’t forget the equinox – a great time to note where east and west really are on your horizon, for the sun rises and sets due east and due west that day and for all practical purposes a few days before and after the equinox.

This year the equinox arrives in the Northern Hemisphere at 7:21 EDT on March 20th.

Oh darn! Yes, that is “daylight time.” For most of the U.S. and Canada “daylight time” began at 2 am, March 13. I say “darn” because they keep making the Daylight Time period longer – starting it sooner and ending it later in the year – and that makes it difficult for little kids to get out and observe when it’s really dark – an hour and a half after sunset. Frequently, by the time it’s dark, it’s too late for them. And, of course, they can observe in the winter when it gets dark early, but frequently our winter nights are too cold for them. Makes it difficult to share the beauty of the night sky and the awe of the universe with our younger citizens!

Beauty — like the delicate glow that reaches up from the western horizon on a March evening and is known as the Zodiacal Light. I wrote more about it last month. However, March is the best time to see it, and you need an area as free of light pollution as you can get. We’re talking about something about as faint as the Milky Way, so your eyes must be dark adapted and you don’t want any competition from the Moon. For March, 2011, you could look the first few days of the month, or wait until the last two weeks of March or the first few days of April. You want to start looking about an hour and 20 minutes after local sunset.


The Moon and Other Planets This Month

  • New Moon, March 2
  • First quarter, March 12
  • Full Moon, March 19
  • Last quarter, March 26.

The crescent Moon makes a nice paring with Venus on the morning of March 1 and joins it once more on the 31st – sort of lunar bookends for those early morning star gazers. Also, it is near Jupiter on March 5th and 6th.

We bid farewell to Jupiter this month, which should be obvious if you checked out the maps showing it and Mercury earlier in this post. But as it sets in the west, Saturn is rising in the east, and it’s a special treat for the users of small telescopes, though they’ll have to stay up late for the best views. (When using a telescope it’s best to look at stars and planets when they’re high in the sky.) Don’t expect to see the rings in binoculars, however; they’re not powerful enough. But any small telescope will show them.

As the month begins Saturn rises about two hours after sunset, which means you’ll get a good look at it about a fist or so above the horizon in the southeast three hours after the Sun sets. By the end of the month it’s rising as the Sun sets – but, of course, on the other side of the sky. The full Moon gets fairly close to it on the 19th. The bright star in the same general vicinity is Spica, a guidepost star we’ll leave for another month.

Spica is about as close to first magnitude as you can get and very blue. Saturn will be at its brightest in March at about magnitude .4, so you should see it as brighter than Spica with a distinct yellow hue. (For more on star colors, how to see them, and what they tell us, see this post.)

Venus is still a lovely “morning star” and stays with us all month, though it rises only about two hours before the Sun, so it is best seen in twilight, low in the southeast. You can’t miss it though. Nothing outshines it except the Moon and the Sun.

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