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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.

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 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: 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.

Prime Time Observing for December 2009 – take the Subaru Challenges!

“Subaru?”  Yep! That’s the Japanese name  for a little purse of celestial gemstones better known in the West as the “Pleiades,” or in many cultures throughout the world as the “Seven Sisters” or some variation of that idea.  And  yes, I said “challenges” – plural, because there are two:

1. how many Pleiads can you see with the naked eye?
2. and can you see – with naked eye, binocular, or telescope – the faint nebulosity that surrounds these stars?

It was that nebulosity that apparently inspired Alfred Lord Tennyson as he penned this famous tribute in Lockesley Hall:

Many a night I saw the Pleiades,
Rising thro’ the mellow shade,
Glitter like a swarm of fireflies
Tangled in a silver braid.

Beautiful, but no words or image can do justice to the live, real-time experience of standing outside on a crisp December evening, raising binoculars to your eyes, and seeing these icy diamonds! And yet all that “cold” blue light really indicates they are very young, very hot stars, all of which are part of an open cluster. But more on that in a minute.  For while the Pleiades lead the observing agenda for any December, in 2009 we have some other great choices as well, including a splendid meteor shower and four nice planets to view – five if you want to get up early. And we’ll add the Pleaides “follower”  – the huge reddish star, Aldebaran – to our list of guidepost stars as well.

So let’s take a look at this month’s prime time chart – a chart that applies to the eastern sky as seen from mid-northern latitudes, 45 minutes after sunset as usual, but with this quibble – you  may not see the Pleiades that early. If you don’t, try locating November’s guidepost star, Capella, in binoculars and sweeping south (to your right), or locate Aldebaran, and sweep upwards with your binoculars. The Pleiades should pop into view. If you still don’t find them, just wait, they’ll appear as the sky gets darker. In any event, you’ll want to wait until later if you’re going to take the challenge. So here’s the chart with our new star, Aldebaran, front and center. Yes, Aldebaran – an Arabic name which means “the follower” and refers to the way this star seems to follow the Pleiades across the sky – and who wouldn’t!

Also, we’ve added a “kite” asterism with Capella – last month’s guidepost star now highinthe northeast – as the dominant star int he asterism. (This is actually the classic constellation Auriga, the Charioteer, but I think the Kite is easier to see and remember.)

Click image for larger view. (Chart derived by modifying Stary Nights Pro screen shot.)

Click here to download  a black-on-white version of the preceding chart, suitable for printing in landscape format.)

OK – here are the highlights we’ll be covering this month:

  • The Pleiades makes a challenging sight for naked eye observation – how many can you count? And they’re a delightful sight in binoculars or small telescopes  – but can you see the nebulosity?
  • The Geminids meteors should put on a terrific show with no interference from the new moon on December 13-14.
  • We draw closer and closer to Mars as we chase it down in our orbit around the Sun and this makes it both brighter to our naked eye and bigger in our telescopes.
  • And speaking of telescopes, great Jupiter, dropping low in the southwest, has its third and last – for several years – close encounter with Neptune.
  • And yes, Saturn is back for early risers with rings that are becoming much easier to see again in asmall telescope!

The Pleiades (Subaru) challenges

Even without binoculars, the Pleaides – also known as “M45” and “the Sevens Sisters” –  can be quite dazzling for those with good eyes and dark skies. Not me. With my aging eyes they tend to blend together and even when I put my glasses on I can only with care see four or five separate stars. Younger eyes do much better. A recent 6-year-old visitor to Driftway Observatory saw them – as many adults do – as the “Little Dipper.” Well the six brightest stars do form a tiny dipper, but the real Little Dipper isn’t nearly as dazzling, is much larger, and is in the north, not the east.

So how many stars do you see? Take your time. Patience is the key. I suggest you get a comfortable beach chair, lean back, relax, and look for at least a solid minute at a time.  How many should you see? I suspect most people who take the time to observe carefully get as many as six to 10.  Walter Scott Houston, who wrote a Sky and Telescope magazine column when astronomy was new to me in the 1950s, counted 18 with the naked eye! And the visual observer I most  admire today, Stephen James O’Meara, says in his book “The Messier Objects:”

Although largely symbolic, the age-old association of the Pleiades with the number seven remains fixed to this day – to the point that some observers swear they cannot see more than seven members, even though the Pleiades contains 10 stars brighter than 6th magnitude. Some observers question how it is possible to see 10 Pleiads in The Seven Sisters (a demonstration of the power of words . . . ) The fact is that almost three times that magic number of stars can be seen without magnification by an astute observer under dark skies.

O’Meara says he logged 17 while observing in Cambridge, MA – which hardly has dark skies.  “The trick” he says, “is to spend a lot of time looking and plotting.” This business of “time on target” is something I find hard to convey to new observers. But it is the key. Another key is simply experience. I frequently see things that those with younger eyes don’t see, simply because I’ve seen them before and know exactly what to expect. Crossen and Tirion in their book “Binocular Astronomy” have this general piece of advice which certainly applies here:

When I first began observing with binoculars I could not see the Rosette Nebula at all, but now it is not difficult for me even under poor sky conditions.

The most important thing in observing is to really look – a mere glance at an object or a field is simply not enough. You must keep your eye at the oculars for at least a full minute at a time.

That said, don’t let the numbers and reports by others discourage you – the Pleiades are yours to enjoy no matter how many you count.  Another noted popular astronomy author, Terrence Dickinson, writes in his book “Nightwatch,” that he has “a tough time seeing more than six stars with the unaided eye, even under excellent conditions,” but he also notes that some of his “astronomy students have reported seeing as many as 11.” And turn binoculars on them and you should be able to easily count between 25 and 50.

The second challenge is more subtle. It involves the nebulosity that shows up in nearly every photograph of this cluster. No, don’t go looking for such a photograph. It will only prejudice you as to both the nebulosity and the fainter stars – and besides, you’ll never match a long exposure photograph with your eyes because film, or the modern CCD accumulate  much more light than our eyes. The Pleiades, as I mentioned, are young stars – less than 50 million years old, and in astronomical terms that means they’re mere babes. (Our star – the Sun – is about 5 billion years old. ) The Pleiades are not far removed from the cosmic womb of gas and dust in which they were formed. Until fairly recently it was assumed that this nebulosity we see was the last wispy remains of the nebulae in which the Pleiades were formed. Today it is more generally thought that this nebulosity is just a happy accident – an entirely different gossamer cloud of gas and dust that is reflecting  the brilliant light of the Pleiades as they pass through it.

In any event, Tennyson seems to reference it when he refers to his “swarm of fireflies” being in a “tangled braid.”  When I look with the naked eye I certainly don’t see it. But be careful. A couple of these stars are quite bright and because they’re close together, their light tends to blend and perhaps give the impression of being surrounded by nebulosity. Perhaps that’s all Tennyson saw, especially as the stars were near the horizon.

So while I assume Tennyson was talking about a naked eye view and perhaps glimpsed the nebulosity in pristine Victorian skies free of modern light pollution, I feel this second challenge is best pursued with binoculars and small telescopes.  While there is nebulosity near several stars, the brightest part is southeast of Merope. (Merope is identified in the downloadable charts at the end of this section.)  So I would look for this first.  What you need to do is look for a difference in the darkness of the background sky in this region. Using binoculars move away from the cluster a tad to avoid the glare – see how dark the sky is? Now move closer to it – do you detect any change in the background brightness?  Again, be careful you don’t confuse the the glow around a bright star with nebulosity.

When you think you have spotted the nebulosity it would be helpful to quickly sketch its location on the provided chart – then compare it with a picture of the Pleiades, such as this one, to see  if your impression of the location and size of the nebulosity matches what the camera reveals.

When to look

To take the challenge you want the Pleiades high in a dark – moonless – sky. In December of 2009 your first opportunity for this will  be around December 5 or 6th.  The Pleiades will be well up about two and a half hours after sunset, and the Moon will not have risen at that time.  As the month progresses, you can wait later and later without interference from the Moon because the Moon rises later each night until New Moon. (And later is better because the Pleiades will be higher in the sky.) Until  about December 19 or 20th – by then the Moon is in the western sky when you look – far away from the Pleiades, but still likely to make it difficult to see the faint stars and nebulosity.  This is a good lesson, however, for looking at any faint astronomical object. When we do that we are constantly balancing these different factors of how high the object is above the horizon – the higher the better because the higher it is the less atmosphere you need to look through to see it – and where the Moon is, because its constantly changing position and brightness wash out the sky anywhere near it.  But as you can see, there’s a solid two-week window when you can take the Pleiades challenge in the middle of this month – assuming the weather cooperates! And, of course, the Pleiades will still be with us through the winter.

Some helpful charts

Click image for larger version. (This chart is derived froma Starry Nights Pro screen shot. A printer firendly version appears in the links which follow.)

There are three printer-friendly charts listed here, but for starters I suggest you download only the first two. They both show the brightest Pleiads but the second one has no names on it and is meant for you to use – and add to  – when taking either challenge.  Put it on a clipboard and take it, a pencil, and a soft red light to your observing location.  Then when you spot something you can mark its location in relation to the brightest stars. Once you’ve done this, take a look at the third chart which shows the Pleaides as seen through a typical pair of binoculars. This chart will tell you whether fainter stars you identified and noted on your chart are in the sky or just your imagination 😉

Chart 1 – Download this chart as a starting point for your observations – and to get to know the names of the Pleiads. (Atlas and Pleione are the parents of the seven sisters.)

Chart 2 – Download this chart to use for note-taking while you’re observing.

Chart 3 – Download this chart to check for faint stars you detected to see if you marked them in the right position.

Finally, compare your observation of the nebulosity with a picture of the Pleiades, such as this one,

The Geminids show December 13-14

Click image to get an enlarged version. (Modified from Starry Nights Pro screen shot.)

(Download a printer friendly version of the preceding chart. )

This is a terrific meteor shower because unlike the Perseids in August and the Leonids in November, you don’t have get up at 3 am for a good view – though for East Coast observers  midnight is best this year, though plenty of meteors should be seen earlier. The radiant point for this shower is in the constellation Gemini and it is already above the eastern horizon as it gets dark.  By about four hours after sunset it is well up in the east. Since the meteors appear to radiate from this point – and you can see them anywhere in the sky – then at this stage more than half the shower meteors should be above the local horizon. So it is really worth it to start looking as early as 7 pm on December 13.

However – there’s always a however – the shower this year is due to peak at 5 hours Universal Time. That translates to midnight EST December 13/14. So my personal plan is to start looking for these meteors at 11 pm and keep looking until 1 am EST.  That gives me the best opportunity to see the most meteors, assuming the weather cooperates.

Here are some tips to get the most out of this shower no matter where you are and when you look:

1. Look up – constantly! Geminid  meteors can appear in any section of the sky – it’s just if you traced them backwards they would seem to come from one area near the constellation Gemini.  (Yes, you’ll see more most likely if you look in the general direction of the radiant point, but you may miss some too, so don’t hesitate to look around at other sections of sky.  When I say “look up” I’m not being facetious. Meteors wait for no man or woman – and there’s no instant replay. I’m amazed at how many meteor watchers don’t follow this simple rule – they talk to companions, and seem to look around at or near ground level, and then grumble when someone else spots a brilliant meteor that they missed.

2. An adjustable beach chair or lounge is great, as well as a sleeping bag or blankets. Even in warm climates, you get cold sitting still for an hour or more under a clear sky.  You’re just one big radiator sending off heat to the universe!

3. Bring binoculars and when you see a bright meteor, use them! Look where the meteor just appeared and you are likely to be rewarded by seeing the trail of smoke it leaves. You may be able to watch this for several seconds as the winds in the upper atmosphere start to twist and disperse it.

Finally, just enjoy being out there. The stars of winter are especially brilliant, not because the skies are clearer and drier (in the northern hemisphere they may be) but because there are simply more bright stars, especially in the region around the constellation Orion, which can be see from just about anywhere on Earth.

Chasing Mars

Here’s the thing – Mars and Earth are closest to one another every 2.1 years – but exactly how close they get each time varies over  a 16-year cycle.So we get close every 2.1 years, but the closest approach happens about every 16 years. This means that some close approaches are much better than others, so the best views of Mars happen every 16 years! And where are we now in that 16 year cycle? Somewhere near the bottom. But play the hand you’re dealt. If you want the best view of Mars in a backyard telescope, then the next four months offer you the best chance you’ll have until about 2014. (In 2012 it will actually be a little worse than this time.) On a positive note, this time Mars is relatively high in the sky for Northern Hemisphere observers and its fun for naked eye observers to just trace its path among background stars. This chart provides you with a starting point for Mars in mid-December.

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

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

Mars will change constantly in December. Each night it will rise earlier and be a bit brighter, doubling in brightness from the beginning to the end of the month – but still outshone by Sirius.  Its position against the background stars also changes. For most of the month it appears to move in the general direction of Regulus. However, on the 21st it stands still, then starts to move in the opposite direction – westward. This is called “retrograde” motion and is caused by our overtaking it as both planets orbit the Sun.

Here are the key numbers and dates for this apparition of Mars, according to Sky and Telescope magazine:

  • Mars will appear larger than 10 seconds in diameter from December through March – that’s big enough to see some features in a backyard telescope.
  • In late January it comes closest but will still appear to be only 14.1 arc seconds in diameter at its largest – on a really good year, such as 2018, it will appear to be over 24 seconds in diameter .
  • In 2012 – when we get another close look – it will actually be a tad smaller at its best because it will be a little farther away.

What should you be able to see? Frankly, not that much. But it’s still fun to try. With a good telescope and good astronomical “seeing” conditions, you should be able to make out some features on Mars such as the northern polar cap, and large, irregular olive drab splotches that stand out against an orange background.

Jupiter’s close encounter with Neptune

Jupiter has had three close encounters with Neptune this year – this is the last. (To read about the first, see this post.)  While Mars is a target for late evening viewing, Jupiter needs to be seen early in the evening, for it sets earlier each night. With a telescope you can start viewing 45 minutes after sunset.

You can find Neptune reasonably near it – using a telescope – all month, but it will be closest during the few nights around December 21st. This changes rapidly, so even if you are a few days either way Neptune quickly gets lost in the background of stars of similar brightness. But on or near December 21 it will be less than one degree away from Jupiter and you should be able to fit both planets in the same field of view if you are using  a low-power, wide-field eyepiece. But keep in mind, at magnitude 8, Neptune is significantly dimmer than Jupiter’s moons.

As a bonus, the crescent Moon is just five degrees away, above the two planets, on December 21. Here’s a finder chart for December 21, 2009 showing Jupiter and Neptune as seen in a low-power telescope view with the image flipped left-to-right, which is what you will see when using a telescope thathas a diagonal mirror. With a reflecting telescope the image also will be flipped AND upside down.

Click image for larger view. (Starry Nights Pro screen shot.)

To download a printer friendly version of the preceding chart, go here.

And Saturn?

The ringed planet – and yes, it’s rings are tilted to us now in such a way that they are again easy to see in a small telescope – is an early morning treat in December.  Although it rises just before midnight at the end of month, it’s not above the horizon until nearly 4 am at the outset. My advice – get up early – about two hours before sunrise. Our chart’s for that time at mid-month and at that time Saturn is well placed in the southeast for telescopic observation. It is one of the brightest “stars” in that section of the sky and easy to pick out with the naked eye.

Click image for larger version. Starry Nights Pro screen shot with annotations added.

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

Prime Time observing for September 2009 – a square, a couch, dancing moons, and more!

Please note: All charts with this post are for observers in mid-nothern latitudes centered on 40° N. If you are 10 or more degrees south or north of that – or if you’re not sure of your latitude – please go here to make your own custom star charts.

Our focus as always is the eastern sky, 45 minutes after sunset, where in September 2009 we’ll find a brilliant Jupiter whose moons play a fascinating game of hide and seek. But our main goal will be to locate and remember  this month’s  two new asterisms the Great (empty) Square and Andromeda’s Couch.

Let’s start with Jupiter, though, because no prime time observer can fail to find Jupiter in the eastern sky starting about half an hour after sunset – there’s simply nothing brighter except the Sun and Moon – well nothing brighter in the eastern early evening sky.  Venus gets brighter than Jupiter, but it never appears in the eastern sky after sunset, though it is in the eastern sky these September mornings an hour or so before sunrise. If you’re one who likes to be up then, be sure to take a look – you can’t miss it!

Though not visible to the naked eye, what’s most fascinating about Jupiter is its four brightest moons. Yes, they look a lot like little stars, even in the telescope, but they are in a rough line with the planet’s mid-section and they continuously change positions around the planet from night to night. In fact these changes can be seen over the course of an hour or so, though at the least you need good binoculars that are held very steady in order to see them. Any small telescope, however, should reveal them easily. For an introduction to observing these four moons see the video and text here. This describes moon events for an extraordinary evening – September 2/3, 2009 – but at some time on many evenings you can observe one or two such events, so even if you miss the events of September 2/3, watching the animation and reading this should help you understand similar events that happen quite often whenever Jupiter is visible.

Of course Jupiter is not going to help you learn the rest of the night sky because like all planets it is constantly changing its position relative to the background stars. But our two bright asterisms for September will help and they are as simple as they come – a square with an arc of three bright stars attached to it.

Click chart for a much larger version.

Click chart for a much larger version.

The first is known as the “Great Square.” I call it the “Great (empty)  Square” because the area inside it is almost completely empty of other naked-eye stars.  The other asterism ties to it like the tail of a kite flying sideways.  It streams off one corner and I think of it as “Andromeda’s Couch.” Of course this is just my memory device – others would simply call this “Andromeda” because that’s the name of the constellation it dominates. I have difficulty seeing the lovely maiden, chained to a rock by looking at these stars and their companions, however. Like most constellations, with Andromeda you need a huge imagination to see the figure these stars represented to the ancients. But knowing Andromeda was a lovely woman who was rescued by Perseus, I like to think of this graceful arc of stars as her couch.  That said, notice three things about it:

1. The bright star at the right – southern – end is also a corner of the Great Square. In fact, it is the brightest star of the four that make up the square, but only by a little.

2. The three stars are pretty equally spaced. Hold your fist at arms length and it should easily fit in the gap between the stars which means there are 10-15 degrees between each star. That’s similar to the spacing between stars inthe Square.

3. There’s another dimmer, but fairly bright star, between the first star ( the one at the corner of the Square)  and the middle one.

And where’s the hero Perseus? he should be nearby, right? Well he’s on his way, rising in the northeast after Cassiopeia, but we’ll leave him for next month when he’s more easily seen.

Looking north

Meanwhile, for those in the northern hemisphere, the bright stars circling Polaris and always visible are well represented this month with the Big Dipper starting to move towards the horizon in the northwest and the “W” of Cassiopeia starting to take the dominant role in the northeast opposite it.

Click chart for a larger image. Northern skies as seen from about 40° N latitude in mid-September..

Click chart for a larger image. Northern skies as seen from about 40° N latitude in mid-September..

Our chart shows the northern celestial pole region about 90 minutes after sunset when skies are about as dark as they get. Will you see all these stars? Depends. First, on how much light pollution there is where you observe. Second, on how well your eyes are dark adapted. You must avoid white light for at least 15 minutes – better still, half an hour – if you wish to see the fainter stars. If you want to test how good your skies and night vision are, look at the Little Dipper. In light-polluted suburbs you will probably see just the three brightest stars. In good rural conditions you should see all seven.  And if you can see them, then this is a good opportunity to try to trace out Draco, one of a handful of constellations whose connect-the-dots pattern actually suggests the mythological figure of a dragon.  I love Draco, but quite honestly, I have to look for it – it doesn’t jump out at me the way the Big Dipper and the “W” do.  And as far as learning the sky – well, you learn the “W,” the Big Dipper and Polaris so you can then find stuff like Draco when you want to find it.

The arrows on the chart indicate the general direction in which the sky appears to move. Stay out an hour and this motion should become obvious to you.

. . . and the rest of the guideposts?

If you’ve located the new September asterisms then it’s time to check for the more familiar ones you might already know, assuming you have been studying the sky month by month.  (If this is your first month, you can skip this section. ) So here are the guidepost stars and asterisms still visible in our September skies.

  • The Summer Triangle is now high overhead, though still favoring the east. Vega, its brightest member, reaches its highest point about an hour after sunset and moves into the western sky. Altair and Deneb are still a bit east, but will cross the meridian within about three hours of sunset.
  • The “Teapot,” marking the area of the Milky Way approaching the center of our galaxy, is due south about an hour after sunset. Well into the southwest you’ll find the red star Antares that marks the heart of the Scorpion.
  • Arcturus (remember, follow the arc of the Big Dipper’s handle to Arcturus) is due west and about 25 degrees above the horizon as twilight ends.
  • The Keystone of Hercules and the circlet that marks the Northern Crown can both be found high in the western sky by tracing a line between Vega and Arcturus.

. . . our journey and September’s planets (2009)

In the course of a night you can still get a glimpse at all the planets – technically – but the truth is both Saturn and Mercury are very difficult to see this month, and Pluto is always just a faint speck visible in large amateur telescopes. Jupiter, as we’ve noted, dominates the evening sky in the southeast. Nearby – visible in binoculars or small telescopes – is Neptune. And an hour or so later, if you want to track it down with binoculars, Uranus will make a good test of your star-hopping skills.  In the morning sky both Mars and Venus are prominent, though Venus gets closer to the Sun throughout the month. At the start of the month Venus rises about three hours before the Sun – by the end of the month this is cut to about two hours – but even in twilight it is so bright it’s hard to miss.

Charts to help you find the  planets follow, but first, let’s look at the solar system from the perspective of someone in a spaceship hovering above it. This shows us where we are in our journey around the Sun and also gives us a chance to examine where the other planets are in relation to us. See if you can translate this perspective into what we see in our sky. The chart below was created with the Solar System Live capability found here. I added the arrows in Photoshop Elements simply to indicate the horizon and directions relating to the earth’s rotation on its axis.

Click image for larger view. Arrows indicate the western and eastern horizons at sunset on September 15, 2009. Smaller arrows show the direction these horizons move at the earth turns on its axis in the course of the night.

Click image for larger view. Arrows indicate the western and eastern horizons at sunset on September 15, 2009. Smaller arrows show the direction these horizons move as the earth turns on its axis in the course of the night. (Planets are not drawn to scale.)

Looking at the horizon line going out to the west – left – you can see that at sunset Saturn is nearly on the horizon.  Use the arrow going to the east (right) and you can see Uranus isn’t quite visible in our night sky at sunset, but Jupiter, Neptune, and Pluto are well beyond the eastern horizon.  Draw an imaginary line from Earth through Jupiter and you’ll see it comes near Neptune – which is why Neptune appears relatively close to Jupiter in our night sky this month, though you’ll need binoculars to find it. (Notice also that Neptune, while a giant planet, is more than twice the distance from the Sun as Jupiter – which is why it is so dim and small in our night sky while Jupiter is bright – and in a telescope – quite large. As these horizon lines rotate,  Saturn sets, followed by Mercury and  then several hours later Pluto and eventually Jupiter. Meanwhile, Uranus rises in the east, followed in the morning hours by Mars and Venus.  Notice also that Pluto is just a tad beyond Neptune these days, though the distance between them will slowly increase.  The chart does show, however, that for a while Neptune was our most distant planet. See how Pluto’s orbit was inside that of Neptune? Don’t forget, Pluto takes 248 earth years to get around the Sun once. These events hold generally true no matter where you are in the world, but they need to be fine tuned for your latitude. Folks in the southern hemisphere, for example, get a much better view of Saturn and Mercury early in the month, than those in the north.

Finding Uranus

Uranus can be found with binoculars – or in exceptional conditions the naked eye – but locating it is an advanced project for those already comfortable with finding the naked eye bright stars and asterisms. You need full darkness, your eyes should be dark adapted, and you should be in an area where light pollution isn’t a serious problem.  That said, finding this planet is relatively easy if you have a decent pair of binoculars and patience.  Here’s a chart to use. After reading the directions below, click on the chart to get a larger version.

This Uranus finder chart is meant to be used firstw ith the naked eye, then binoculars. The red circle represents the typical view with wide field 7X or 8X binoculars. See text for instructions. Click on chart for larger view.

This Uranus finder chart is for September, 2009, about two hours after sunset. It is meant to be used first with the naked eye, then binoculars. The red circle represents the typical view with wide field 7X or 8X binoculars. Included on this chart are many faint stars that can be seen only with binoculars. See text for instructions. Click on chart for larger view. (Made from Starry Nights Pro with modifications.)

Start your search by locating Jupiter and the Great Square. You may also see Fomalhaut, a first magnitude guidepost star that will be introduced in October.

Next look below the Great Square for the “Circlet.” This is a well-known asterism in the constellation Pisces – but in typical suburban skies it is a difficult object and you may be able to pick out just three of the brightest stars in it with your naked eye. In rural skies you should be able to see most of these stars with the naked eye, but try to locate them with binoculars. The entire Circlet probably will not fit in a single binocular field of view, but enough of it should so you know what you are seeing.

Now use your binoculars to try to locate the trapezoid of fainter stars below the Circlet. This little unnamed trapezoid will probably fit in your binocular field of view. The faintest star of these four is just a bit brighter than Uranus, so that gives you an idea of what you seek.

Finally, with your binoculars scan up and to the right (west)  of this trapezoid and you should pick up an arc of three stars all about the same brightness. The third – the highest – of these is Uranus. While you won’t see a disc, you may notice that it shines with a steadier light than the other two. This is typical of planets. In a good telescope Uranus will show a tiny disc and perhaps a greenish tinge, but to the casual observe may be easily mistaken for a star.

Finding Neptune

Neptune is both easier and harder to find than Uranus. Again, binoculars and a dark sky are needed. What makes it easier is it’s near Jupiter. What makes it harder, is it’s signifcantly fainter than Uranus – so faint that whether you see it or not will depend on how dark your skies are.  You will need this little finder chart, however, to pick it out of the starry background.

Finding Neptune requires binoculars, or a small telescope, and patience. Fortunately, Jupiter drops us right in the neighborhood! See text for complete directions - and click on chart to get an elarged version. (Made with screen shot from Starry Nights Pro. I added names and arrow.)

Finding Neptune requires binoculars, or a small telescope, and patience. Fortunately, Jupiter drops us right in the neighborhood! See text for complete directions - and click on chart to get an enlarged version. This charts is for mid-September, 2009, about two hours after sunset. Neptune will appear to move slightly towards Jupiter during the course of the month. (Made with screen shot from Starry Nights Pro. I added names and arrow.)

Step 1 – find Jupiter, the brightest “star” in the eastern sky. The red circle represents a widefield binocular view. Your binoculars may show a smaller field. Also see if you can spot the two bright stars in our chart that are to the left – east – of Jupiter. They are bright enough so you should be able to see them even in typical suburban skies. In any case, you certainly should be able to find them with binoculars by first locating Jupiter, then scanning to the left – eastward.

Step 2 – after locating the two bright stars, use binoculars to look for the arc of three dimmer stars above them. These three are about the same brightness as Uranus and just at the edge of naked eye visibility under excellent, dark skies. For most people this means they will be seen only in binoculars. Neptune is to their left – east – as indicated.

And for early risers – Venus and Mars!

A crescent moon and Venus dominate the morning sky in the east, along with Mars and half a dozen bright "winter" guidepost stars. Click chart for larger image. SLightly modified screen shot from Starry Nights Pro.

A crescent moon and Venus dominate the morning sky in the east, along with Mars and half a dozen bright "winter" guidepost stars. Click chart for larger image. SLightly modified screen shot from Starry Nights Pro.

Don’t miss the autumnal equinox!

OK – if you’re in the southern hemisphere, this marks the start of spring. In the northern hemisphere, it’s autumn. In either case, it’s when the Sun crosses the celestial equator and day and night are almost of equal length.

The autumnal equinox this year is on September 22, 2009, at  21:28 Universal Time.

So what? Well, if you’re just starting out in star gazing, this is a great time to get your bearings at your observing site. That is, on or about September 22 – a few days either way won’t matter much – note where the Sun either rises or sets. That marks the due east – or due west – point on your horizon and from that you can easily figure out where north and south are.

It’s also the day on which the reading of your equatorial sundial switches from one plate to the other. That is, in the north you go from the north-facing dial plate to the south-facing (underneath) one.  See our equatorial wrist dial project. if you want to know more about this.

And finally, I find it cool that day and night are nearly of equal length. For one thing, that means the stars get a break. For the next six months here in the north we’ll have longer nights and thus more time to enjoy the night sky.

August 2009 – and all the planets have shown up for the party!

That’s the good news – the bad news is the “party” is an all-nighter. That is, if you really want too see all the planets – and maybe little, demoted Pluto as well – you need to start at dusk and stay at your task well into the wee hours of morning.  For Pluto, you will also need a powerful telescope and better charts than I’ll provide here, but the others can all be seen with the naked eye or binoculars.

But what I like about this situation is it makes it easy – even for those of us using nothing but the naked eye, which is really the focus of this web site  – to  see most planets on a single night and to get a sense of how their position in the sky relates to our position in the solar system and where we all are on our annual journey around  the Sun.

Astronomy is always about two realities – the reality we see and the reality we know. The trick is learning to merge these two so that when you see something in the night sky, you are familiar enough with what is really going on that what you see makes perfect sense, given what you know.


The best example of this is provided by the two major planets this month – Jupiter and Saturn. The chart above shows the reality we know. It shows where all the planets are at the start of August if you could get  above the plane of the solar system and look down at them. Study it. This is from the online orrery at “Solar System Live.” (http://www.fourmilab.ch/solar/)  I drew the bar across it to represents our horizon – the line between night and day –  and the arrows show the direction the bar is moving as night progresses. To the left this shows how, from our perspective, things are setting in the west – and to the right, how they are rising in the east.

Notice that in this view Saturn is near our western horizon and Jupiter near the eastern horizon. That’s the situation right around sunset. But the sky is too bright then for us to see even bright planets. We have to wait about 45 minutes. At that point, Saturn will look like a first magnitude star about 12 degrees above the horizon almost due west – azimuth 266 degrees – in the early part of the month.

Switch to the east and Jupiter is not so shy. It is at magnitude -2.8 (nothing gets brighter than this except Venus, the Moon, and the Sun), but it is still hugging the horizon. Chances are it is too close for you to see. Give it another 45 minutes – 90 minutes after sunset – and it will be about nine degrees above the horizon a bit south of east. For my latitude – 42 degrees north – it will be at azimuth 118. But the exact position isn’t too critical, since it is so bright and there’s nothing in that general vicinity at this time that will compete with it.

This will change slowly as the month goes on – that is, Saturn gets closer to the horizon at sunset each night and Jupiter rises earlier, until on August 14th Jupiter is rising in the east as the Sun is setting in the west.

Did you notice on the solar system view that Mercury is right over there near the western horizon as well? It is, but this happens to be a fairly poor showing for what is always an elusive planet to catch. Sky and Telescope gives this instruction: “Observers near 40° north can look for it 5° above the western horizon a half hour after sunset from August 6 to August 18th.” Yep – and it will be near magnitude “0” – but you will need a very clear western horizon to see it, and I suggest you search for it with binoculars.  Earlier in the month is better than later for both Saturn and Mercury. As the month goes on Saturn not only gets  closer to the horizon, but also closer to Mercury – and this will make  both very difficult to see. By August 17 the two planets are just 3 degrees apart, but then Mercury is only 2 degrees above the horizon and Saturn about 6.

Much easier to find are our two morning planets, Venus and Mars. Both can be spotted, without strain, with the naked eye. But Venus is by far the easiest. It is a brilliant  magnitude -4 – brighter even than Jupiter, which by this time is well over in the southwest, and should be easy to see low in the east northeast by 3:30 am. By the end of the month you’ll have to wait until about 4:30 am for it to be easily seen – but that’s still two and half hours ahead of sunrise.

Mars is a bit more of a problem, though it rises well ahead of Venus. At 3 am August 1 it is a first magnitude “star” about 7 degrees to the north of Aldebaran, also first magnitude,  and both are roughly 15 degrees above the horizon, a bit north of east. Because Aldebaran is a very red star, it will be interesting to compare it with the “red” planet, but it’s best to wait another hour to do this so both are higher in the sky and not as affected by the atmosphere, which tends to make every bright object colorful.

By the end of the month Mars is higher at 3 am, but Aldebaran is higher still. Mars will form an interesting triangle, though, with Aldebaran and another very red star, Betelgeuse. In fact, if you are up at that hour you get a preview of the early winter sky with the bright constellations of Auriga, Taurus, Gemni, and Orion coming into view, and Mars in the middle of them as our chart shows.

Mars early in th emorning at the end of themonth. Click for larger version. (This chart uses a screen shot from Starry Nights software which I have then annotated.)

Mars early in th emorning at the end of themonth. Click for larger version. (This chart uses a screen shot from Starry Nights software which I have then annotated.)

Returning to the evening sky, this remains a good year to track down Neptune and Uranus with binoculars. Both are relatively easy to find, but offer special challenges.

Notice on the solar system chart how Neptune is roughly in line with Jupiter as we view both from Earth. On August first a careful study of the Jupiter region with binoculars around 10 pm will reveal Neptune at about magnitude 8 and only two degrees to the north (left) – but finding it can be tricky.  Try putting Jupiter in the right-hand edge of your field – or even move your binoculars so Jupiter just drops out of the right hand edge. That way the glare from it won’t interfere with your view.  At that point Neptune should be pretty close to the center of your field of view. There are several stars nearby and both Neptune and Jupiter are changing position as the month goes on. Here’s a chart for August 1.

Neptune and Jupiter at the first of August, 2009. (Clickfor larger view.) (This chart uses a screen shot from Starry Nights software which I have then annotated.)

Neptune and Jupiter at the first of August, 2009. (Clickfor larger view.) (This chart uses a screen shot from Starry Nights software which I have then annotated.)

By the middle of the month, they have drifted a bit farther apart, and there’s a row of sixth magnitude stars in a gentle arc between them. If you compare the first chart and this second one you will see these stars and how the position of the planets change relative to them.

Neptune and Jupiter near the middle of August, 2009. (This chart uses a screen shot from Starry Nights software which I have then annotated.)

Neptune and Jupiter near the middle of August, 2009. (This chart uses a screen shot from Starry Nights software which I have then annotated.)

By the end of the month these same stars are closer to Neptune and the gap between Neptune and Jupiter is almost five degrees. That means they both probably fit in the same binocular field, but just barely.

If you look at the horizon line on our solar system chart – especially the eastern one – and note the direction it is moving, then you can see how our view will change during the night. As Jupiter and Neptune get higher we eventually get to a point where Uranus comes into view, then, well after midnight, Mars and Venus put in an appearance.

Uranus is easier to see than Neptune because it’s significantly brighter – about magnitude 6.  We also get a special break this month, for Uranus will form a wide “double star” with 20 Piscium, a star that is just a tad brighter than the planet. But this makes it easy to identify.  Here’s my way to locate it. First, trace out a few asterism in the sky south of east. (The following chart is for 11 pm EDT, August 1, at 40° North – but should serve as a general guide for almost any location.)

This charts helps you locate thegeneral area inw hich to find Uranus. Click forlarger version. (This chart uses a screen shot from Starry Nights software which I have then annotated.)

This charts helps you locate thegeneral area inw hich to find Uranus. Click forlarger version. (This chart uses a screen shot from Starry Nights software which I have then annotated.)

Next, you want to zero in on the Circlet of Pisces and an unnamed trapezoid below it.

Tracking down Uranus with binoculars. (This chart uses a screen shot from Starry Nights software which I have then annotated.)

Tracking down Uranus with binoculars. (This chart uses a screen shot from Starry Nights software which I have then annotated.)

The Circlet will not fit quite in the typical binocular field of view. The trapezoid should fit and maybe Uranus at the same time – but the way I find Uranus is to find the trapezoid in my binoculars, then move up so that only its top two stars are visible in the bottom of my field of view. Now up and to the right are two almost identical stars – the higher one is Uranus. It is about half a degree above 20 Piscium, a star that is just a tad brighter, though you will be challenged to tell the difference.  (The charts show only those stars you can expect to see with your binoculars – but depending on the binoculars and conditions, you may not see all of these stars.) Uranus is on the brighter side of magnitude 6 and at this point, at least 10 degrees above the horizon. Waiting until later in the night – or later in the month, this will only get easier as Uranus will get higher.  But as the month goes on it will pull away a little from 20 Piscium. By August 30 they are a degree apart and instead of Uranus being directly above 20 Piscium, it will have moved above and to the right – westward.

And Pluto? I wouldn’t try to hunt it down even with my 15-inch telescope.  Although it is relatively high in the south once it gets really dark, it is much too faint to see in anything except large amateur scopes. And to make matters worse, it has lots of competition, for it is above the Teapot in the middle of the Milky Way, and at magnitude 14, just a faint, faint dot among many, many other faint dots. Better to spend your time exploring the Milky Way itself. See: August Guideposts: Asterisms guide you along the Milky Way.

This is the general area within which you can find Pluto this month. But theplanet is faint and buried with the faint stars of the Milky Way.  (This chart uses a screen shot from Starry Nights software.)

This is the general area within which you can find Pluto this month. But theplanet is faint and buried with the faint stars of the Milky Way. (This chart uses a screen shot from Starry Nights software.)

A dreamy, planet-filled, midsummer night!

The sky will be filled with planets about 45 minutes before daybreak - BUT, only Jupiter and Venus will be easy to spot witht he naked eye. You might spot Mars, but binoculars will help and they certainly are needed for the rest. Neptune will be right next to Jupiter looking like a faint star, Uranus will be brighter, but refer to the chart for it. Mercury? You'll need ideal conditions to see it and that slither of Moon.

The sky will be filled with planets about 45 minutes before daybreak on the morning of June 21 - BUT, only Jupiter and Venus will be easy to spot with the naked eye. You might spot Mars, but binoculars will help and they certainly are needed for the rest. Neptune will be right next to Jupiter looking like a faint star, Uranus will be brighter, but refer to the chart for it. Mercury? You'll need ideal conditions to see it and that slither of Moon. (Click for much larger view.) This an all other charts here are screen shots taken from Starry Nights Pro software and slightly modified for this use.

June 20-21, 2009 – Midsummer Night –  is the shortest night of the year, but it is chock full of planets – all of them! ( Yes, we had a similar opportunity in May, and that was great fun – but it gets a tad better in June and there’s something a bit magical about Midsummer Night!)

In the hours before midnight you can enjoy Saturn in the western sky and as it sets shortly after midnight,  you can enjoy Jupiter and Neptune rising in the East. Pluto is there as well, low in the west, but it is so faint you’ll need a large telescope and lots of patience to track it down. Uranus will be the next one up, rising about 1 am, but not becoming easy to see for another hour or two. By 3 am Mars and Venus will have broken the eastern horizon. I don’t know how easy it will be to spot Mars with the naked eye. It will be just one degree from brilliant Venus and although it will be first magnitude, that will still be five magnitudes dimmer than Venus! In binoculars, however, it should be easy.

The difficult catch will be Mercury. My best guess is about 45 minutes before local sunrise (about 4:25 am for me in Westport, MA) it may be high enough if there are no clouds on the eastern horizon and the sky may still be dark enough. The thinnest of crescent moons may be a guide, assuming you can see it! Mercury will be about six degrees below the Moon and to the right – close enough to fit with the Moon in a wide-field binocular view, though typical 10X50 binoculars will not fit the two in the same field. Still, at zero magnitude it will be bright. Both of these are north of east – Mercury at about azimuth 67° and the Moon at  about azimuth 62°.

Frankly, I’ll consider myself very lucky if I spot Mercury – and I probably won’t have the patience to hunt for Pluto. If the skies are clear enough to see it, there will be too many other things to catch my interest, particularly near the southern Milky Way. But it would be kind of fun to pull an all-nighter – especially since this is the shortest night of the year – and to see all of what are currently called “planets” on the same evening. So if the weather is cooperative, I’ll probably start observing about 11 pm EDT.  And I’ll do my observing at a favorite location near the ocean where I have a great view of the eastern horizon – in fact, all horizons!

The charts which follow provide a guide to finding Neptune and Uranus.

Finding Neptune is easy, as long as you remember that at magnitude 8 it is much fainter than 5th magnitude Mu Capricorni, or the moons of Jupiter, all of which will be visible in a small telescope, or good binoculars held steady.

Finding Neptune is easy, as long as you remember that at magnitude 8 it is much fainter than 5th magnitude Mu Capricorni, or even the four brightest moons of Jupiter, all of which will be visible in a small telescope, or good binoculars held steady. Jupiter itself is second only to Venus in brightness at magnitude -4.6 (Click for much larger view.)

Uranus is a challenge to find with binoculars, though at magnitude 6 it will appear reasonably bright. Theproblem is, it's in a section of the sky without bright, maked eye guide stars. I dentify thegeneral search region by looking at the large chart at the start of this post. Then use this chart and search for the rectangle of 5th magnitude stars. Find themand it's a short star-hop up to Uranus.

Uranus is a challenge to find with binoculars, though at magnitude 6 it will appear reasonably bright. The problem is, it's in a section of the sky without bright, naked-eye guide stars. It does fit on aline between Jupiter and Venus and is about 27 degrees from Jupiter on that line. Identify the general search region by looking at the large chart at the start of this post. Then use this chart and search for the rectangle of 5th magnitude stars. Find them and it's a short star-hop up to Uranus which will appear to be the twin of the star closest to it. (Click for a much larger image.)

Dawn patrol: 5 Planets and a crescent moon – this will be cool!

OK, I’m normally up at this hour so it’s a no brainer for me – I’m heading to the Allens Pond Bird Sanctuary parking lotwhere there’s a great view of the eastern horizon, preferably on the morning of May 21. That’s when I expect a wonder-full view of five planets and the waning crescent moon. I plan to be there at 3 am, but it should get especially interesting between 4 am and 4:30 am. Later than that? Well, we’ll be in a race with the dawn – everything will get higher, as dawn approaches, making it easier to see –  BUT – so will the Sun which rises that day at 5:19 am. So the sky will get lighter making things harder to see.  And, of course, there’s always the weather question – but in this case, all the players will be around right into early June in approximately the same positions, except, of course, the moon. So while I will aim for May 21, weather will determine the actual observing date.

All of this is local time and date for 41.5 north latitude and 71 west longitude. But a good guide for elsewhere in the world is to simply find out the time of local sunrise, then start looking 90 minutes  before that. All the action as viewed from the Northern Hemisphere is  between east and southeast and the territory will be nicely defined – and easily found – by bright Jupiter,  brilliant Venus, and the Moon. This makes it an excellent opportunity for folks not familiar witht he outer planets Neptune and Uranus to take alook for them.

The more difficult targets will be Mars and Uranus – Neptune, since it will be so close to Jupiter, should be relatively easy – though binoculars will be needed for Uranus and Neptune and, of course, a small telescope willmake it all more fun. Here’s a chart from Starry Nights software  for what I expect to see, given clear skies of course:

(click for larger chart)

(click for larger chart)

For me the key is to look at this chart – look at the sky – and then keep firmly in mind what is really going on – which is this:

(click to enlarge)

(click to enlarge)

To understand how this display relates to what we actually see in the sky, consider that the Earth is rotating counterclockwise, and all the planets are revolving around the Sun counterclockwise.

That means that as the Sun slips below your horizon on the May 20 Saturn will already be high in your western sky. It will set by 2:30 am. But at around 4 am on May 21 you will encounter Jupiter and Neptune first and they will be highest. (That’s what the first line projecting from Earth represents.) Then as you let your eye move towards the horizon – counterclockwise, towards the Sun – you encounter Uranus, Venus. and last, Mars – as shown by the other lines. Not shown is the Moon which will be in line between Venus and Mars.

This representation is modified slightly from Solar System Live.  While all the planets are roughly on the same plane, if their orbits are represented by a blue line it means they are above the plane of the Earth. If it is represented by a green line – as is the case with the five morning planets on May 21, it means they are below the plane of the Earth.

The most difficult planet to find is likely to be Uranus. If  we have exceptionally clear skies and you have exceptionally good eyes you may be able to see it with your naked eye – but for most people in most locations binoculars will be essential. Here’s a typical 7-degree binocular field showing Uranus and stars to magnitude 8 from Starry Nights software. The star 24 Piscium is the brightest in the field at magnitude 5 – the other named stars in the circle – and Uranus – are magnitude 6. Fortunately, the general position of this field is easy to see by drawing a line between Jupiter and Venus (see the first chart). As you move from Venus up towards Jupiter, count three binoculars fields along this line  – Uranus  should be in the third field. Notice that Uranus is the last “star” in an arc of four reaching upward from the bottom of the field – the forth one being just below the field if you put Uranus at dead center.

(click to enlarge)

(click to enlarge)

Neptune is much easier to find. See this posting for details on it.

This is a good event for naked eye and binocular users. Yes, a small telescope will help. Jupiter and Venus will be fun to see in a telescope. Neptune and Uranus are too small to show anything except a tiny disc and Mars is a long way from us showing a disc only one-eighth that of Jupiter, so no details will be visible there either.

Interesting note: A friend in Austrailia said he would look for this, so I made him a quick chart for how things would look at 6 am in Australia on May 21. Compare that chart (below) with the view we get (first chart on this post) in North America.  Note how high Fomalhaut is for them – not to mention Jupiter and Neptune – and, of course, they look to the northeast as we look to the southeast.

The view from Sydney, Australia on the morning of May 21. (Click for larger image.)

The view from Sydney, Australia on the morning of May 21. (Click for larger image.)

Neptune – meet Jupiter! All the angles on an AM event

September update: Neptune continues a relative close relationship with Jupiter in September 2009 and will be getting closer again later this year. To see Neptune’s position  in September 2009  go here and scroll down to the section on “Finding Neptune.”

Jupiter passes so close to Neptune this month (April 2009) you’ll be able to see both planets at the same time in binoculars or a small telescope – assuming you don’t mind getting up before the Sun 😉

OK, maybe you do mind getting up before the Sun – so don’t bother with this one. There will be two more opportunities this year, once in July and once in December. (Yes, planetary conjunctions tend to come in threes.  My own rationale for trying to catch this in May is based on the fact that these are normal hours for  me and even if they weren’t, our weather is so fickle I don’t pass up good opportunities – who knows what July and/or December will bring!)

The date to aim for is May 27, but a week either side of that will  work for either binocular or telescope view. Why bother? Because it’s events like these that give you a handle on size and distance of various objects and Neptune just isn’t that easy to find onits own, so this is a good way to go about finding it. But let’s look at the particulars. Here are a couple of charts made from Starry Nights software. The first shows you a naked eye view of the sky on May 27, 2009 at 4 am EDT  from about 42 degrees north latitude. The lesson here is simple, look low in the southeast – you may spot brilliant Venus very close to the horizon in the east and you certainly should see Jupiter, roughly a quarter way up the sky and just south of southeast. Nothing else will be nearly as bright as these two, though Venus will have Jupiter beat by about two magnitudes.  (The first magnitude  “star” near Venus will be Mars.)

naked eye view of Jupiter, Venus and Mars. Though Neptune is there, it's too faint to be seenw itht he naked eye.

Naked eye view of Jupiter, Venus and Mars. Though Neptune is there, it's too faint to be seen with the naked eye, though it should make n easy binocular target. (Click image for large version.)

This second view (below) shows what you’ll see in binoculars on May 27. A few days before that Jupiter will be even closer to the 5th magnitude star Mu Capricorni which is just a bit brighter than Jupiter’s brightest moons. Each day after May 27 it will be moving a tad to the east -left.  Neptune, at 8th magnitude, will be significantly fainter and appear  like a star in binoculars. It should be easier to see than Jupiter’s moons simply because it’s not so close as to be caught in the glare of the giant planet.  But it will certainly be easier to see in a low-power, wide-field telescope view. (Aim for a field of view of close to one degree to capture both Jupiter and Neptune nicely. )  Neptune should have a bluish hue and will show a tiny disc of about 2.3 seconds of arc in diameter.

Jupiter and Neptune as seen in binoculars on May 27, 2009, low in  the southeast about 4 am.

Jupiter and Neptune as seen in binoculars on May 27, 2009, low in the southeast about 4 am.(Click to enlarge.)

So what can you expect to see in the telescope? Not much. Jupiter’s disc is 41 seconds in diameter at this point. It’s largest moon, Gannymeade, shows a disc of about 1.5 seconds and Neptune’s disc is just a tad larger than that at 2.3 seconds. Why so small? After all, isn’t Neptune one of the “gas giants.”

Yes. But first off, it’s is significanty smaller than Jupiter – roughly one third the size. (It’s still about four times the diameter of Earth, however. For a neat guide to the sizes ofthe planets, see this Web site.)

Jupiter is about three time the diameter of Neptune and both are far, far larger than the Earth.

Jupiter is about three times the diameter of Neptune and both are far, far larger than the Earth.

But look at the distance. Jupiter is at 5.2 astronomical units  from Earth this month – Neptune is at  more than 30 astronomical units – almost six times as far away.   (An astronomical unit is about 93 million miles, the distance of the Earth from the Sun.) Does that make sense, then? Do the math! it’s simple.

Move Neptune as close to us as Jupiter and it would appear to be roughly six times larger. Six times 2.3 is 13.8. We said Jupiter was about three times bigger than Neptune. Three times 13.8 is 41.4 – and Jupiter shows in our sky a disc of 41.6 seconds at the end of the month.  Don’t you like those numbers? All approximations, but they come out very close and thus make sense.

So, will you really see the disc of Neptune? Yes – but after getting your wide angle view of both planets at once, pump up the power to get a better view of Neptune. It won’t be great – but hey, remember – you are seeing it by reflected sunlight that has taken over four hours to reach Neptune and another fours hours to bounce back here to you.

And what about Mu Capticorni? Well, it’s a nice little power house as well. As you look at it, recall that it is about 90 light years away, yet it appears about as bright as our Sun would appear  if our Sun were just 30 light years away! That means that like so many of the naked-eye stars we see, Mu is significantly brighter than our Sun.  All of that is neough to get me out of bed at 3:30 am and trundle on out to catch the sight.  Besides – I love mornings – especially those last couple hours of darkness – so peaceful, so quiet, so rich in contemplative ambiance.

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