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Jim's Journal
This time of year is one of the two best, IMO, for finding really cool things up there in the night sky.
Late winter/Early spring is great for viewing one of the most recognizeable constellations in the Northern Hemisphere.
And we're going to have fun with it and its neighbors.
But first...FIRST.....there's something that you won't get a chance to see for another generation - all five planets visible to the naked eye in the sky at the same time. The added bonus is that you get to see a beautiful star cluster, too, and all you need are your peepers. A pair of binoculars will work, too, but they're not required.
Here's a ]little overview of what to look for. You'll be looking for horizon to horizon for those bright non-twinking objects (cool note: Stars twinkle. Planets don't unless they're close to the horizon). Jupiter will be the big bright one to the East and Venus will be even brighter to the West. In between them will be the semi-bright Saturn. Between Saturn and Venus you'll find the reddish Mars. The toughest to find will be Mercury. It'll be tucked under Venus, low on the horizon. You'll need a nice clear night, an uncluttered horizon, and almost no ground lights to spot it. If you get it then you've done great! If not, enjoy the four you can see easily.
But why stop while you're there? Drop down and to the right of Saturn and find Orion . The most distinguishable feature is the three horizontal stars known as Orion's Belt. If you have really good binoculars you can find the Orion Nebula (located just under the second star in what would be the "scabbard" hanging off the Belt"). The Orion Nebula is one of the universe's most active star birthplaces and a favorite of the Hubble Space Telescope.
While you're looking at Orion, note the red star that makes one of his shoulders. That's Betelgeuse. It's a really freaking big star (so big that if you replaced the Sun with it, it would extend past the orbit of Jupiter) and the redness is caused by its advanced age. The other bright star which is diagonally opposite Betelgeuse is Rigel. Rigel is the 7th brightest star in the sky, some 40,000 times brighter than our own sun.
But while we're looking at bright stuff, take a look to the left and slightly lower than Orion. That really bright star there is Sirius, the brightest star in the whole sky - 23 times brighter than the sun. Much of that brightness is due to its closeness to us - only 8.6 light years. Rigel, by comparison is 775 light years away. Sirius is part of the Constellation called Canis Major (AKA: The Big Dog).
And here's another one to find, if you're lucky this time of year. Slide over a little farther to the left and down, near the horizon (try looking for this one later in the night). There'll be another bright star there that's part of the smallest constellation I know, Canis Minor (AKA: The Little Dog). Canis Major and Canis Minor serve as companions to Orion - his faithful hunting dogs. The star you see there is Procyon . Canis Minor is ade of two stars, but ht eother is so faint that Canis Minor is often called the "Lone Star Constellation".
But what are Orion and his hunting dogs hunting? Well, remember where we left Mars? Look just a little down and to the left. You'll see a "V"-shape, headed by a reddish star that looks a bit like Mars. That star is Aldebaran and it's the brightest star in the constellation Taurus . The bull is fearsome! Grrrr!
If you haven't gotten a crick in your neck quite yet, come up a little form Aldebaran and see the Pleiades, otherwise known as the Seven Sisters or The Most Often Misspelled Thing in the Sky. On a normal night you can pick out six to seven of them with the naked eye. A clear night will reveal as many as a dozen. With a decent pair of binoculars, you'll see dozens! There's your star cluster. Yahoo!
The trio of Sirius, Procyon, and Betelgeuse form the Winter Trangle, just one of the great reason to gaze at the stars on a clear night this time of year.
Just about everyone can find the Big Dipper (or the Plough, if you're in Britain) this time of year. It's likely the most recognizeable feature of the sky and the end of winter is a great time to see it and some of its notable neighbors.
The first neat fact about the Just about everyone can find the Big Dipper (or the Plough, if you're in Britain) this time of year. It's likely the most recognizeable feature of the sky and the end of winter is a great time to see it and some of its notable neighbors.
The first neat fact about the Big Dipper is that it's not a constellation of itself. The proper name for it is an "asterism" - a group of stars that make their own distinctive shape. You've probably seen other asterisms before: The Hyades (which makes up the horns of Taurus), Orion's Belt, and the Sword of Orion are perhaps the most notable. It's part of a constellation called Ursa Major or The Great Bear. Most folks, myself included would be hard pressed to identify the rest of the Great Bear, but that's okay. Most astronomers have a hard time finding it with the naked eye, too. It's not the easiest constallation to find, mostly because it's made up of relatively dim stars and because it's spread out over a good chunk of the sky.
There are a couple features about the Big Dipper I find interesting and to my knowledge they make it a truly unique bunch of stars. First, unlike many other constellations, the Big Dipper doesn't have any notable stars. They are all of the same approximate magnitude and none of them stand out to the point where they have memorable names. There aren't many constelations in the Northern Hemisphere for which this is true and certainly none as famous as the Big Dipper. Second, the Big Dipper has something called an "optical double". This is where two stars seem close enough to be thought to orbit each other, even though they don't. The optical double formed in the handle of the Big Dipper is the only one I can recall readily seen by the naked eye. To find this neat little sight, we have to find the Dipper first.
Look in the Northern Sky, slightly to the West. The Dipper will be hanging upside-down with the handle arcing gently to your right and the broad part of the dipper opening to the left. Once you've found that, the optical double is a snap to find. Look closely at the second star in the handle. If you don't have a lot of gorund light, and the weather's reasonably clear, you should see a small star right next to a brighter one.
From the Big Dipper, you can find four other constellations easily. We'll take the easiest one first - the one most folks learn as children. The back two stars of the Dipper (the ones which, right now will be the ones highest in the sky) are called the "pointer stars". Make a straight line betwen them then extend that line out from the bowl of the dipper to the first visible star. That star is Polaris, the North Star, the most visible star in Ursa Minor. It lies almost exactly on the North Magnetic Pole. It wasn't always the North Star, though. Because of a phenomenon known as precission, the north star shifts from one star to the next. This happens because the Earth doesn't rotate perfectly on its axis. There is a slight wobble that causes the north and south poles to slowly move in a cirle every 25,000 years or so which means that we won't have to worry about it for a while. :) Of all the stars which are likely to become "north stars" in the future, Polaris is the one closest to Magnetic North we'll ever know.
Let's go back to our pointer stars, and head in a line moving the other way. You'll come to a brightsh star named Regulus the most luminous star in the constellation Leo. Regulus means "heart of the lion", which makes sense to me considering it's smack in the middle of Leo. Oh, and there's another asterism here for you asterism collectors. Regulus is the bottom of what's called the "sickle of Leo" which you can find my moving up and following the curve of stars that form Leo's head.
Okay, let's go back to the Dipper. Do you notice how the stars of the handle make a gentle arc? Well, keep following that arc to Arcturus. Arcturus is the brightest star in Bootes the Herdsman. No, don't blame me for the name of these constellations. I would have named it "The Kite" because that's all I ever see when I look at Bootes. and I have no idea who Bootes is, either. I guess he was a famous herdsman who herded sheep really well and so, hey, a constellation. Arcturus is the fourth-brightest star in the sky and shines nearly as bright as Sirus over there in Canis Major (remember Canis Major?).
One more constellation and you can rest your next. Luckily, this one sits fairly low in the sky this time of year. Take that line you drew from the Dipper to Arcturus and make a beeline to Spica. Spica is the luminary of what may be the rarest thing nowadays, Virgo the...err..Virgin. Again, this constellation doens't look much like a virgin, but I assume that she was named by sailors out on a months-long voyage. I think we're lucky that all the constellations didn't get these kind of names. In the Southern Hemisphere, as a matter of fact, there's a wealth of nautically-named constellations (the Sextant, the Argo, the Compass, etc).
So there you go....five constellations for the price of one famous one!
Believe it or not, if you take these with the ones that group around Orion, you have most of the constellations in the sky during the early spring.
Enjoy!