Check out the Milky Way
Thursday, August 4, 2011
One of the best astronomical sights to observe at this time of year is so large it is difficult to miss. All you have to do is go outside, find a nice, dark-sky place far away from city lights and look up.
It is the Milky Way, the wide star-path that is the plain of our galaxy. The reason the stars are so concentrated is we are looking at the galaxy like we would a cookie if we held it up and turned it flat looking at the edge.
The solar system we live in is located way out almost to the outer edge of the galaxy. If we look south we are looking toward the center. If we look north we are looking out toward the sparsely populated outer edge.
If you are in a dark-sky place and looking south the stars of the Milky Way seem to be all bunched up and thick because, well, because they are, in a sense.
We are looking through the thick central bulge of the galaxy, and as such there is much more to see. Here it is possible to see globular clusters, open clusters, and various other assorted forms of nebula and faint fuzzies.
Starting with a pair of binoculars start by looking south. This is the realm of Sagittarius, the Archer, and Scorpius, the Scorpion.
Just above the spout on the teapot asterism of Sagittarius is the center of our galaxy. Think of it as the steam coming out of the spout.
It does not look as bright as it really is because here we are looking through layers and layers of dust and gas that hides the brightness of all the stars.
Start here, or at the stinger of Scorpius, and look for all the goodies that are there. Follow the star-stream up to almost overhead to find Cygnus, the Swan or the Northern Cross. Look along the length of the neck of the swan for what seems to be a dark area where no stars can be seen.
This is "The Great Rift." It is not so much there are no stars to be seen there, but here is a great cloud of interstellar gas and dust so think that the light of the stars behind it cannot penetrate.
This dark area is comparable to the "Coal Sack," another great dark area located in southern hemisphere skies near the constellation Crux.
Continue your sweep north and you will notice that stars are thinning. We are looking through the less-dense area of the Milky Way, out toward the outside. Keep on going north to reach the "W" of Cassiopeia.
There are some celestial goodies here, but they are far apart and difficult to locate. But don't lose heart, they are there, a good star map will help you find them. Happy hunting.
Sky Watch:
First quarter moon, Saturday, August 6. Saturn is still an excellent early evening telescopic sight. The rings continue to open. Today, the crescent will be just below Spica in Virgo, the Maiden. Aug. 7, the moon moves in on Antares, and if you are really interested, on Tuesday, Aug. 9, the moon will be about four degrees below and right of Pluto. You won't be able to see it, but at least you will have the satisfaction of knowing where it is.
If you are up early in the morning try catching slightly dim Mars. It will be almost due east about an hour before sunrise. Watch it each day as it moves from just over the upraised club of Orion into the feet area of Gemini. Next Wednesday, Aug. 10, at about 8 p.m. MDT find an almost-full moon in the southeast. Bring your binoculars and start watching the moon at about 8:15 p.m. MDT. Watch the upper right limb of the moon and if you live somewhere near 40 degrees north at about twenty minutes after eight the star Albaldah, or pi Sagittari, will come out from behind the moon. This is called an occultation, and this one started before sunset. We will miss the start, but not the ending.
Next Week:
More astronomical blathering.