Astronomy: Download observation charts for free

July 19, 2006 12:00 am

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By RYC RIENKS

Following on the previous two columns we move to one of the best ways yet devised for learning our way around the night skies - The Constellations. The value of constellations has always been their grouping of stars in manageable bits while adding a mystical element compatible with the cosmic grandeur. If you select for study a constellation while it is high in the sky you will be able to enjoy the primary stars as well as some of the unusual objects within its boundaries. But first, what do we know about Constellations?

We know they are groups of stars that evoke images of ancient mythological heroes, various animals, kitchen implements, some drawing tools, and even parts of a boat. We also know the components of these groups do not share common space. The Stars of the Big Dipper, for example, are moving in different directions, each from the other. We arrived on the scene while it looks like a dipper. In England the same stars are called "The Plough". As eons pass the shape will elongate. Were we to stick around long enough it would dramatically change shape, looking more like a dipper that had been run over by a pickup truck.

Our Constellations can be considered as being divided into two groups: the Zodiacal Constellations, and, those others. The Zodiac consists of a band of the sky 16 wide centered on the ecliptic, divided into 12 sections of 30. Each section was named for the constellation within. In order of appearance these are: Aries, Pisces, Aquarius, Capricornus, Sagittarius, Scorpius, Libra, Virgo, Leo, Cancer, Gemini, Taurus, and, once again, Aries. They ride the ecliptic across the night sky along with the Sun, the Moon, and the planets. Currently, if you look low above the southern horizon, you will see Scorpius following Libra as the evening sky darkens. Look for the bright red star ANTARES, in Scorpius. This is the eye of the Scorpion. Consult your star chart for the constellation diagrams.

Most of the constellations also have their roots in antiquity, many named by Ptolemy, for example. Interestingly, some were named as recently as the mid-18th century by French astronomer Nicolas-Louis de Lacaille.

Now for some field work. Go out on a clear night and select one you like the look of. Try your hand at making a drawing of it. Next, using a star map, label the stars you drew. Be warned - many are identified with Greek lower case letters. You can copy those squiggles and after a bit of practice you'll be recognizing and drawing them well. Follow up by adding the marks you find on the star chart that indicate galaxies, nebulas, clusters and double stars. The next clear night, using the stars you drew and the marks you added you can try to observe a galaxy or a star cluster. Many of these objects can be found with just your eye. When you can, try binoculars or a telescope. You might even come up with a double star. Read on.

Binoculars and spotting scopes abound in our area and they can easily be turned to the night sky. Low power binocular observing is excellent as it allows you to see a larger area of the sky. Higher power gives you a tiny peephole to peer through and that makes it really hard to locate any specific target.

Binoculars usually are identified by their power and the size of aperture. A familiar marking is this: 7 X 50. That means seven power (X) with 50 mm (2 inch) diameter at the big end. Seven power you can hold steady. Even 8x to 10x works well, though for smaller detail on the moon, a rest is helpful. Anything more powerful may need a tripod or other brace to quell the vibration of your heartbeat or the wind.

If you have binoculars available, start with them. Don't feel compelled to spend a lot of money. I've had many a pleasant night's observing using $8.00 thrift store 10 X 50 Tasco binoculars.

Naked-eye sights: A rising, non-Zodiacal constellation you should locate is Lyra. It represents the Lyre its shape resembles this musical instrument. At its head is VEGA, a brilliant A0 spectral type star. Vega shines at magnitude 0.1, the 5th brightest star and one of the stars that make up the summer triangle. In 10,000 years Vega will replace Polaris as our pole star.

Binocular sights: Near Vega you should be able to locate Epsilon Lyrae. Once you do, Congratulations! This, as you will see, turns out to be a double. For a second sight try locating M6, the Butterfly Cluster in Scorpius. Seven power binoculars reveal over 30 stars in a cluster that lies almost 2000 light years from Earth.

Telescope sights: Look at Epsilon Lyrae. Yes we know it is a double, but with higher magnification you will see that it is a double-double. For an extra thrill, locate M57, the Ring Nebula, in Lyra. This smoke-ring shaped nebula is about 4100 light years from us. The light you see left M57 over 4,000 years ago. I wonder how it has changed. In 4000 years more we will know.

Astronomy Resources

Suggested publication: Reader's Choice. This week let's try a different approach. Rather than me make a suggestion I would like you, the reader, to suggest a publication you have enjoyed or found useful. I'm eager to see your choice. Who knows? I'll probably learn something new. For now, the best resource we all have is the library. I recommend it most heartily.

URLs to recommended web sites: We have discussed star charts you can download for no charge. Now, learn a lot about ways to use them effectively with your telescope. The book "Starhopping", written by Ed Kauffman, is free and well worth delving into. It will prove to be a valuable resource on a continuing basis. You'll find it at: There should be a link labeled "Starhopping", click on this.