Events for May 2010: A good month to get to know the planets – especially Uranus!

Note: While many of the following events are visible throughout the world, the exact time and location in the sky can be dependent upon your latitude and longitude. Since I’m in the mid-northern latitudes (41.5N, 71.1W), specifics, where place-and-time-dependent, are calculated for this location.

   

Planets to scale - source unknown, but a very nice illustration! Click for larger image.

All  month – This a great month to meet planets – you’ll find they each have a distinctive appearance to the naked eye – and this is an especially good year to get out your binoculars and meet Uranus. A special window of opportunity opens in the morning starting about May 25, 2010.

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

 

But before delving into that exploration, just get out early on any May evening and you’ll find three bright planets waiting for you, and on certain nights, the Moon will be close to one or the other providing a sure guide to locating the planet. But even without the Moon, the easiest to spot is Venus. It will be low in the northwest, but only the Moon and Sun outshine it. Venus can be an “evening star,” as it is now, or a “morning star,” as it will be near the end of the year, but whichever it is there’s no star or planet that outshines it. So you’ll always know Venus by its brilliance.

A crescent Moon plays tag with Venus on May 15 and 16th.  Exactly how close it gets depends on where you are. For folks in southern Asia and northern Africa, the Moon will actually occult Venus – pass in front of it. Here in Westport, MA (41.5N,71.1W), it’s not nearly so dramatic, but still will make  a nice scene in the evening twilight. On the 15th the Moon is about six degrees below Venus, and on the next evening it’s about six degrees above it. (Remember, your fist held at arm’s length covers about 10 degrees.)

Mars is easy to spot this month for three reasons. First, it’s high in the southwest. Second, it has a distinctively reddish cast. And third, it’s moving between the Beehive – which we met in March – and Regulus, one of our bright guidepost stars, whipping along at the rate of about half a degree a day. That means each day it will cover a space against the background of fixed stars that is the size of the full Moon. To put this into perspective, Uranus takes about 44 days to cover the same distance! On May 19 the Moon will be about six degrees below Mars.

Finally, Saturn is shining at almost the same brightness as another nearby guidepost star, Spica. This is about as dim as Saturn gets and the reason, as backyard telescope users know, is that Saturn’s rings are titled almost edge-on to us. That means they just make thin spikes pointing out to either side of the planet when seen in a telescope – interesting, but not the beauty we’re used to. It also means that the planet and rings aren’t reflecting as much sunlight our way as they usually do and thus Saturn appears relatively dim – though still as bright as the 16th brightest star, Spica. Saturn is more subtle than Mars in coloration, but it always seems to have a soft yellow glow, and when I see a bright, yellowish “star” where no bright star belongs, I know it’s Saturn.

Well – I should modify that last statement a bit. When I see such a “star” near the ecliptic I know it’s Saturn. The ecliptic is the path of the Sun across our sky, and the planets appear within a wide band that stretches about one fist above or below the ecliptic. To get a sense of this band, let your eyes wander from Saturn to Mars to Venus. The arc you see connecting these planets pretty well defines the general area of the sky where you’ll always see the planets. Another way to think of this is the ecliptic is the plane of our solar system – the planets circle the sun in what amounts to a huge disc. And you can sense that as you look at them in the evening sky this May.

Of course the Moon appears in this same general band of sky and comes fairly close to the planets from our point of view. On May 22 the Moon will be about 8 degrees below Saturn. However, keep in mind that the Moon will be about 10 days old at that time and quite bright, so it will drown out most of the stars near it, though Saturn should be bright enough to still see easily.

And now, as promised, Uranus!

We’re missing Mercury this month. It puts in a very minor appearance in the morning sky late in the month and won’t be easy to see, but we do have Jupiter rising in the morning sky, and it is easily visible before dawn after mid-month in the east. It’s second in brightness only to Venus. What’s more, it’s going to be our guide for finding Uranus. The ancients were very familiar with the five “wandering stars” we just mentioned – Mercury, Venus, Mars, Jupiter and Saturn. They watched them regularly and knew well where to find them. So can you. But the ancients never saw Uranus, though it is just on the edge of naked eye visibility. I’ve never been able to see it except with binoculars or a telescope. And when you do find it with binoculars, it looks just like a faint star.

In fact, on March 13, 1781, the English astronomer William Herschell pointed one of his large telescopes toward some faint stars in the constellation of Gemini and suddenly discovered that one of them just didn’t look like a star.  In fact, as he increased magnification he saw it as a distinct disc and he was quite pleased at himself for having discovered – a comet! That’s right. At that time no one was thinking much about more planets.  Comets were all the rage, though. In fact, when Herschell checked four days later, his discovery had changed position slightly and he took this as proof that it was a comet.

But it wasn’t. Herschell’s new comet never developed a tail.  It was soon determined that Herschell had not only discovered a new planet, but in doing so he had doubled the size of the known solar system. Uranus, while big enough to swallow 64 Earths, was in fact more than twice as far from the Sun than Saturn, which at that time marked the end of the known solar system.  And that great distance is, of course, why Uranus appears so small and so dim to us. Even with a good-sized amateur telescope you can just tell you are looking at a planet and not a star. And while it has rings, as Saturn does, they’re much too faint to see.

Let Jupiter help you out!

But this year Uranus will be simple for you to find if you have binoculars. All you’ll have to do is find Jupiter, then use your binoculars and the appropriate chart below to determine which “star” is really Herschell’s new planet. You can begin this process about May 25, and the opportunity will be there through June. Yes, that means getting out there about 3:30-4 am and that may not fit your schedule. If so, don’t despair. Jupiter and Uranus will be in the early evening sky in the fall and in winter as well, so there will be two other “windows” when locating Uranus with binoculars will be easy this year. Both of these will allow viewing in the evening hours that most people keep.  But do take advantage of one of these. Otherwise you have to wait about 26 years for another chance! (Of course you can find Uranus any year – but it’s much easier to do so when it is right next to a bright planet like Jupiter.)

Here are charts that you can use in May and June. They  show the position of Uranus and Jupiter  about 3:30 am on May 25, June 6, and June 30, 2010.  Study each chart and you will see that in the new few weeks Uranus will appear to move to the right while Jupiter moves to the left.  They will be closest together on June 8 but should still fit in the same binocular field at the end of the month. (The circle represents a typical binocular field ifor 10X50 binoculars.  Depending on exactly what you’re using, your field of view may be larger.)  Do enlarge the image by clicking on it and do note that you can download a printer-friendly version of each chart using the links below.

To make any sense of this you really have to click the image and look at the larger version. You can then select one or more of the panels from the list below to get a printer-friendly PDF file that you can use outside. (Charts prepared form Starry Nights Pro screen shots.)

For a printer-friendly version of the appropriate chart for on or near May 25, 2010, click here.

For a printer-friendly version of the appropriate chart for on or near June 6, 2010, click here.

For a printer-friendly version of the appropriate chart for on or near June 30, 2010, click here.

What’s in a name?

And since we’ll be talking about Urnaus a lot this year, let’s get the silliness surrounding its name out of our heads right now. The best way to pronounce the name Uranus is “YOOR-ah-nuss”, not “your anus” or “urine us.” Remember that – or risk having your audiance – especially if they’re shcool children – distracted by a bad case of the giggles!

Sometimes I wish we had listened to Herschell. When he discovered this planet he named his discovery “Georgium Sidus” which means the Georgian Planet in honor of King George III of England. I doubt that this idea went over well in America at that time – in March 1981, just before Herschell made his discovery, the colonies officially ratified the Articles of Confederation and Perpetual Union – essentially our first Constitution. Of course Herschell’s wise choice of this name led to him getting a lifelong stipend!   But the name didn’t stick and astronomers applied others and it was Bode of Germany who suggested Uranus, the ancient Greek deity of the heavens. It took another 50 years or so for that to catch on, but now it’s not about to change.

Night-by-night summary

All month – Look for the bright planets along the ecliptic from east to west – Saturn, Mars, and Venus.

May 4-7 – Don’t get excited – this is not a big event – but I would feel remiss if I didn’t mention the Delta Aquarid meteor shower. In the early morning hours, northern hemisphere observers may see a few bright meteors associated with this shower, but this event is much better in the southern hemisphere, and this year no matter where you observe a waning Moon approaching last quarter will provide unwelcome competition, brightening the sky and drowning out all but the brighter meteors. ould be good on any morn

May 6 – Last quarter Moon lights up the  morning sky.

May 13 – New Moon.

May 15, 16 – A crescent Moon plays tag with Venus.  Exactly how close it gets depends on where you are. For folks in southern Asia and northern Africa, the Moon will actually occult Venus. Here in Westport, MA (41.5N,71.1W),  it’s not nearly so dramatic but still will make  a nice scene in the evening twilight. On the 15th the Moon is about six degrees below Venus and on the next evening it’s about six degrees above it.

May 19 – The Moon is about six degrees below Mars.

May 20 – First quarter Moon.

May 22 – A 10-day-old Moon is about eight degrees below Saturn.

May 25 – Good day to start your quest for Uranus with Jupiter as your guide in the early morning sky.

May 27 – Full Moon.

Note: There is one category of special events worth checking on that is not listed here because the events very specific to where you live and when you observe. These are events involving man-made objects in space – the passages of the International Space Station, Iridium flares, and other bright satellites. There are two excellent  sources for such events. I urge you to check both, see how they differ, and then make your own decision as to what works best for you.

• The first is provided by Spaceweather, and you’ll find it here.

• The second is the Heavens Above site, and while this requires you to register, the process is painless and free and the result is a lot of information that is specific to your location. Once registered and logged in, study the menu – there’s a wealth of information on satellites and many other astronomical objects.