Flying into autumn with Pegasus

Thursday, September 15, 2011

For me nothing says autumn better than the constellation Pegasus, the Flying Horse.

This time of the year it rises in the east just after sunset to begin its majestic parade across the sky. Pegasus is one of the larger constellations and can be easily found, if you know where to look, and that is where I come in.

Go outside to your favorite dark-sky place about an hour after sunset and look east. Now, today would not be a good day to do that because the just-past-full moon is rising at about the same time as Pegasus. So wait a couple of days.

Then it will be easy to find, just look for four bright stars making what looks like a very large baseball diamond with home base at the bottom and second base at the top.

I think the ancient star map makers were playing a joke on us because all we see of Pegasus it his front half, just the body, head, and front legs. Also they have made him upside down with his head down and his legs sticking up in the air.

The legs extend up and to the right from Scheat (second base), and the neck extends in a curve out from Markab (first base). At the end of the neck is a star called Enif, or nose.

After finding Enif use your binoculars to look about four degrees above it for a nice little globular star cluster, the Pegasus Cluster (M-15).

Pegasus comes to us out of the mythological story of Perseus and Andromeda. You might recall how Andromeda's mother, Cassiopeia, bragged about how her daughter was more beautiful than any other being.

This put a twist in the knickers of the Nerids, daughters of the sea god Poseidon, who thought they were the most beautiful. In any case, Andromeda ends up chained to a rock as a sacrifice to the sea monster Poseidon had sent to ravage the coast as punishment for Cassiopeia's boast.

Right about then Perseus comes by riding Pegasus after having slain the evil Gorgon, Medusa, and sees the fair maiden in dire straits and rescues her by turning the monster into stone using the head of Medusa and everyone lives happily after.

Not to mention, the whole crew ends up as constellations in the sky. We will be dealing with the rest of them in future columns.

SKY WATCH: Full moon was Monday, August 12. This was the "Harvest Moon." Tonight, and the following night, the moon will be near bright Jupiter. Look in the east after 10pm MDT. On Aug. 17, the moon will travel to the neighborhood of the small star cluster, Pleiades. As the moon continues its travels eastward on Friday, Sept. 23, at about 3 a.m. MDT a very slender crescent moon will visit the planet Mars. Mars is just returning from its journey to the far side of the sun. The bright planet Jupiter is rising earlier each evening at about 9 p.m. MDT. Now is a good time to start looking for the elusive "False dawn of Omar Khayyam," otherwise known as the Zodiacal Light. The light is really sunlight reflecting off of bazillions of tiny dust grains scattered along the ecliptic, or the path the sun and planets travel. It can be found by looking east about two hours before sunrise on any moonless morning. Look for a faint glow that looks sort of like what the Milky Way does. It could extend one-third to one-half way to the zenith along the ecliptic.

NEXT WEEK: Perseus and Andromeda, and more astronomical blathering.

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