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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 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 ?  ūüėČ

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‚Äôs view. Here’s a typical example of what you will see.

Luna-See – Let the Moon of August 2011 be your guide!

Anyone can find the Moon – so why not use it to help you learn the sky?

Moon and Mars in the early morning sky, August 25, 2011.

Each month the Moon in its travels comes near some planets, bright stars, and asterisms. If you look on the right night this month you’ll be able to use the Moon to help you find:

  • Saturn and Spica (August 2, 3 & 4)
  • Antares and the Scorpion (August 7)
  • The Arrowhead with the asteroid Vesta (August 13)
  • The Hockey Stick and Jupiter (August 19)
  • Pleiades, Hyades, & Aldebaran (August 22)
  • Taurus (August 23)
  • Mars with the heavenly twins, Castor and Pollux (August 25)

Whew! That’s a whole lot. ¬†And you’ll find when and exactly where to look by using the charts below. You have to pick the right night and you have to ¬†be ready to approximate – the charts are a rough guide as to when and where to look – and use binoculars to help you find otherwise bright stars because the Moon light will tend to wash out ¬†all but the brightest.

I say “rough guide” because these charts are all for my specific location on the Northeast Coast of the United States. The moon moves about half a degree (its diameter) an hour, so observers on the West Coast will see it in a little different location than I do. But the charts should give a good general guide and help you know the night sky better – and as a bonus you’ll begin to develop a feel for the rather complex motion of the Moon each month.

Notice that for the first half of the month the Moon is in the early evening sky. For the second half it is in the morning sky. The Moon’s image in the charts is about three times as big as it actually is in order to show the phase clearly.

Click any chart to get a larger version. All charts are prepared from Starry Nights Pro screen shots.

Saturn and Spica, (August 2, 3 & 4)

Antares and the Scorpion (August 7)

The Arrowhead with the asteroid Vesta (August 13)

The Hockey Stick and Jupiter (August 19)

Pleiades, Hyades, & Aldebaran (August 22)

Taurus (August 23)

Mars with the heavenly twins, Castor and Pollux (August 25)

Moon phases

  • New Moon ¬†– July 31
  • First Quarter – August 6
  • Full – August 13
  • Last Quarter -August 21
  • New Moon – August 28

Events-February 2010 – Happy Valentines Day Jupiter – we’re onto you!

Ah, to be romantic in mid-winter!¬† And this year, on February 14th, we have Jupiter¬† – king of the gods – being joined by Venus – goddess of love, beauty, and fertility –¬† beside the soft glow of a slim crescent moon! Is that appropriate, or what? (OK, we’ll ignore the fact that Jupiter is married to Juno.)¬† The question is, will we be able to see this little tryst? Or will it be so close to the horizon – and the Sun – that it will remain a figment of our imaginations. One thing I’m sure¬† of – it will be a challenge. Other challenges this month for naked eye and binoculars include:

Jupiter, Venus, and the Moon

Sky and Telescope describes this encounter this way: “Venus and Jupiter appear 2 degrees apart on February 14th, when an ultraslim young Moon joins them in a tight formation.”¬† Yep! “ultraslim” is right. When I asked Starry Nights Pro to show me this scene I couldn’t even see the moon it was so slim! That’s because I’m on the East Coast. West Coast observers will see a moon that’s a bit older – and thus larger – so they will have a better shot; but I’ll try. Here’s the screen shot from Starry Nights for 15 minutes after sunset at my latitude, about 42 degrees north.

Click image for larger view. Printer-friendly version linked below.

Click here to download a black-on-white (printer-friendly) version of this chart.

If you want to see this live, you first need an unobstructed western horizon. Then, a lot of luck in terms of no clouds. If you meet those two requirements, then a good pair of binoculars, or a small telescope would be handy. Be careful though – make sure the Sun has fully set before you start looking. I plan to wait 5 minutes, then I’ll start scanning the horizon. I expect to pick up Venus first.¬† Jupiter will be a bit higher, but also dimmer, so it should pop out second and be in the same binocular field of view as Venus. I expect the moon will be last to put in an appearance, but if I put Venus to the left side of my binocular field, I should be able to pick up the Moon on the other side.

Normally, of course, Venus and Jupiter are easy targets – downright dazzling. But now we’re talking about finding them in bright twilight and very near the horizon. Thirty minutes after sunset Venus will be barely one degree above the horizon – that’s about the width of your pinky held at arm’s length – without gloves!¬† And Jupiter will be about three degrees above the horizon. Venus sets just 38 minutes after the Sun and Jupiter about 50 minutes. See why it’s going to be hard to surprise these celestial lovers?

But if you get clouded out, don’t despair – they actually get closer during the next couple of days, though the moon will quickly rise much higher and so not be an intimate part of the picture. Now if it’s clear enough to see these three – or even two of them, then I’m going to wait another 50 minutes to see if I can detect the elusive zodiacal light.

See the Zodiacal Light

Now this is something much different. You don’t need a totally clear horizon to see the zodiacal light, or binoculars, but you do need total darkness and that means little-to-no light pollution. I feel I have a good shot at it from my favorite ocean-front observing point where I have a clear horizon to the west with no cities to create light domes there. Evenings in February and March – and mornings in September and October – are the best time for folks at mid-northern latitudes to look for this.

The zodiacal light is roughly the same intensity as the Milky Way, so if you can see the Milky Way from your chosen location, then you should be able to pick up this faint glow.  Like the Milky Way, it stretches over a good deal of sky. It is widest near the horizon and gets narrower as it rises towards the zenith.  You want to look for this roughly 80 minutes after sunset. You can check for an exact time for your location by getting information from here on when astronomical twilight ends. (The drop-down menu on that page specifies the times for astronomical twilight.)  As astronomical twilight ends you want to start looking. As with any faint object, your eyes need to be dark adapted, so I am assuming you have been out for at least 15 minutes with no white light to dazzle you. If you try to look for this earlier, you may confuse it with twilight. Much later and it is not as bright, for what we are seeing is sunlight reflecting off  interplanetary dust particles Рdust particles that orbit in the same plane as the planets Рthe area we call the zodiac Рand thus the name for this phenomena, zodiacal light.

If you see it,  reflect on this explanation from Wikipedia:

The material producing the zodiacal light is located in a lens-shaped volume of space centered on the sun and extending well out beyond the orbit of Earth. This material is known as the interplanetary dust cloud. Since most of the material is located near the plane of the solar system, the zodiacal light is seen along the ecliptic. The amount of material needed to produce the observed zodiacal light is amazingly small. If it were in the form of 1 mm particles, each with the same albedo (reflecting power) as Earth’s moon, each particle would be 8 km from its neighbors.

For the metric-challenged (that includes me) that means one dust particle every five miles! And that causes all that light?! Awesome!

Watch the bright Asteroid Vesta dance through Leo

This spring you get a chance to follow one of the brightest asteroids as it dances about the constellation Leo. This will be particularly easy to find with binoculars on the night¬† of February 16 (February 17 UT) , or the night¬†before or after that one.¬† The fast-moving asteroid will be close then to the second brightest star in the easy-to-spot asterism of Leo’s Sickle. To find this, look east about three hours after sunset. Here’s what you should see with the naked eye.

Click image for larger version of this chart. Chart was developed form Starry Nights screen shot.

Click here to download a black-on-white (printer-friendly) version of this chart.

Once you are sure you have found Gamma Leo, then look at it in your binoculars.  You should see something like what is shown in the circle, though your binoculars may show a somewhat larger field. What is neat here is that Vesta is moving right between Gamma and 40 Leonis and it will take it about three nights to complete the journey.  You can start looking for Vesta earlier, however, if you want. It will enter the field of view shown at the lower left about February 7. And it will leave the circled region, exiting to the upper right, on about February 25. It would be fun to spot it on several nights and use the printer-friendly chart, linked below, to mark your own observations of its movement.

Click image for larger view. Printer-friendly link below. (From Starry Nights screen shot.)

Click here to download a black-on-white (printer-friendly) version of this chart.

Catch the Demon in Demise

I wrote about Algol the “Demon Star” in the posting for October, but it’ s still well placed for viewing in February, and if you look at the right time, you’ll catch it in mid-eclipse, which is cool.

Every 2.3 days Algol dims like clockwork, but it is only at its dimmest for about two hours, so to see it in this condition you really need to be watching at the right two hours. Fortunately, there are several places that will give you a list of times when this occurs – but many of them will be while normal people are sleeping – and many more will be during daylight hours. However, each month there should be one or two dates when it is really a good time for you to catch Algol doing its thing.

Most of the listings I know of for Algol “minima” give date and time in Universal Time. What I like about the one at Sky and Telescope magazine, is it will calculate a list of coming Algol minima for you – and give you the Universal Time, plus your local time. So it’s easy to glance over it and see when it will be most convenient – weather permitting – for you to take a look. In my case, February 2010 gives me a couple of opportunities worth noting:

  • 02/07/2010 @ 09:45 pm
  • 02/10/2010 @ 06:35 pm

You can learn much more about the minima of Algol Рand get specific predictions for any date with translations to your local time  by visiting this page at Sky and Telescope.

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