Sep 01

September 2006

Whats Up in the Sky September, 2006

Autumn Constellations

I always look forward to this time of year (at least now that I’m retired from teaching) because the conditions for backyard observing are good. Cool nights, clear skies, and a variety of interesting objects often combine for a fun night of sky watching. And, since the planets are not well-placed for viewing, we can concentrate on some other things

I often tell people that a good place to begin in amateur astronomy is to identify the major constellations just using the naked eye. Go out about an hour after sunset, when the brightest stars are beginning to appear. Face south and look straight up. You will see the bright star Vega (VEE ga) which is in the constellation Lyra and is one of the stars in the Summer Triangle. At 27 light years (LY) distant it is one of the closest bright stars.

To the left and a little above Vega is Deneb (DEN ebb), the tail of Cygnus, the swan. Deneb is one of the most luminous stars known, 60,000 times brighter than the sun. If it were as close to us as Alpha Centauri (our nearest stellar neighbor at 4.4 LY) we could read by its light. It is the second star in the Summer Triangle.

Directly below these two stars is the third member of the Summer Triangle, Altair, in the constellation Aquila, the eagle. According to legend, Aquila belonged to Zeus, the king of the gods, who rewarded the bird for all his years of faithful service with a place among the stars.

Continue down to the southern horizon and look for Sagittarius. This constellation resembles a teapot with its spout pointing to the right (west) and tipped down. On a dark, moonless night you can see the Milky Way rising from the teapots spout and arching overhead.

Turn now toward the northwest and look for the Big Dipper just over the treetops. Its handle arches to the left (west) and the bowl is on the right (north). Follow the two northernmost bowl stars up to Polaris, the North Star, which is the end star in the handle of the Little Dipper. Returning to the handle, look closely at the middle star, Mizar, and see if you can spot its faint companion, Alcor.

Follow the arc formed by the three stars down and left to Arcturus, the bright star near the western horizon. Arcturus is at the bottom of the constellation Bootes, the herdsman, which looks like a tall, slanted house or kite extending up from the horizon.

It will be helpful to identify these stars and constellations if you use a star chart which can easily be found online or in several popular astronomy magazines. This will aid your exploration of all the cool things up in the sky.

This month in history:

Sept. 1: Pioneer 11 first spacecraft to fly past Saturn – 1979
Sept. 3: Viking 2 lands on Mars – 1976
Sept. 5: Voyager 1 launched – 1977
Sept. 8: Star Trek premiers – 1966
Sept. 12: Gemini 11 launched – 1966
Sept. 15: Lost in Space premiers – 1965
Sept. 22: Pioneer 10 leaves the solar system – 1990
Sept. 23: The Jetsons premiers – 1962
Sept. 30: Daily communication with Pioneer 11 ends – 1995

Here are this months viewing highlights:

Planets this month: Jupiter is very low in the SW evening sky. Venus close to horizon in ENE before dawn – look 45 min. before sunrise. Saturn can be found 10° to the upper right of Venus.
Sept. 4: Uranus is at opposition.
Sept. 6: Venus less than 1° from the star Regulus.
Sept. 7: Closest Full Moon (222,000 mi.)of the year.
Sept. 11-12: Binoculars show Jupiter about one moon diameter from the star Zubenelgenubi.
Sept. 14: Last-quarter Moon.
Sept. 22: New Moon.
Sept. 23: Autumnal Equinox – 12:03 a.m.
Sept. 30: First quarter Moon.

Peter Burkey – SAAA President