Astronomy program features Jupiter and the Andromeda galaxy
Published 3:27 pm Friday, October 8, 2010
Closer and brighter than at any time since 1963, the planet Jupiter makes a bold statement of its presence on clear autumn nights this year. At present, Jupiter appears four times brighter than any star.
During October, Jupiter rises in the east at sunset, is overhead at midnight, and sets in the west at sunrise. It is, therefore, directly opposite or in opposition to the sun.
It is true of all planets in the solar system that when opposite the sun from earth they appear largest and brightest. Because the orbits of the planets are not perfect circles, the planets distances from earth changes from one opposition to the next causing their maximum apparent brightness to change as well. This explains the favorability of this particular opposition of Jupiter during 2010.
Autumn nights also allow a good opportunity to see our galactic next door neighbor, the Andromeda Galaxy. Andromeda is the only galaxy other than our own Milky Way that can be seen with the unaided eye. No telescope is required.
Andromeda appears as a small patch of light in the constellation Andromeda for which it is named. The crisp clear air that often prevails during October permits an especially good opportunity to see it unobstructed by mist or haze.
Because light travels at a finite speed, any celestial object we observe is seen as it existed in the past. Moonlight is one and one half seconds old when we see it. The light of the sun began its journey to your eyes eight minutes before. Jupiters light at&bsp; this opposition has aged about 32 minutes. A star picked at random, perhaps 500 years on average.
What about Andromeda?
Without the aid of binoculars or telescope, every object we see in the night sky, every star or misty spot, resides in and is a part of our own galaxy, the Milky Way. Andromeda is different. It is a separate galaxy entirely.
Rather than measured in minutes, hours or years, Andromedas distance is measured in millennia. When you see the Andromeda Galaxy, you are looking more than two million years into the past, a distance defined as two million light years. And in terms of the universe itself, Andromeda is one of our closest neighbors.
On Saturday night, October 9th, after sunset, astronomers will be on the hilltop behind FENCE with telescopes set up to observe Jupiter, the Andromeda Galaxy, and other celestial wonders too numerous to mention.
Unfortunately, our most recent meetings were cancelled due to rain or cloudy weather. However, the forecast for Saturday night as of this writing appears to be good.
No experience is necessary. All views are free! Bring warm clothes and binoculars if you have them.
We hope to see you after sunset on Saturday, October 9th! And as our PBS friend Jack Horkheimer always says, Keep looking up!