Go Stargazing! October Edition

Jupiter is up all night long by month’s end.

 That’s because on Friday night, October 28, Earth passes between the Sun and Jupiter.  In this alignment (‘opposition’) Jupiter rises at dusk and sets at dawn.  Already, Jupiter is a late evening object rising just after 8:30 pm on October 1.  Face east at the appropriate time and look for the brightest thing there—that’ll be Jupiter.   Once up, Jupiter remains up the rest of the night, so the King of Planets continues to dominate the western pre-dawn sky. 

Jupiter as Seen by Voyager 1
Creative Commons License photo credit: Undertow851

Venus begins to emerge from the Sun’s glare late this month.  Look for it low in the west southwest in twilight, especially as Halloween approaches.  This is the beginning of Venus’ apparition as evening star; it gets higher and easier to see for the rest of this year and is spectacular for about the first half of 2012. 

Mars is now a bit higher in the east at dawn.

It has now brightened to rival first magnitude stars such as Regulus in Leo. As it moves through dim Cancer and towards Leo, Mars is quite identifiable.  Saturn is behind the Sun and invisible.  It is directly in line with the Sun on October 13.  We thus say Saturn is in conjunction with the Sun on that date. 

Antares, brightest star of Scorpius, the Scorpion, sets in the southwest during twilight, with the ‘teapot’ of Sagittarius to its upper left.  Meanwhile, the Summer Triangle is virtually overhead.  As the stars of summer shift to the west, those of autumn fill the eastern sky.   Watch the Great Square of Pegasus rise in the east.  Note that we look towards the center of our galaxy when we face between Scorpius and Sagittarius.  When facing the Great Square or especially south and east of that, we face out of the plane of our galaxy, a direction where there are fewer bright stars.

Assyrian or Babylonian
Creative Commons License photo credit: Ed Bierman

That’s why the large expanse of sky rising under Pegasus seems devoid of bright stars.

For this reason, ancient Babylonians designated this broad area of sky as the ‘Celestial Sea’, and filled it watery constellations.  The only bright star in this whole expanse of our sky is Fomalhaut in the southeast, which marks the mouth of the Southern Fish.  Between the ‘teapot’ of Sagittarius and Jupiter (in Aries, the Ram), are three dim zodiacal constellations—Capricornus, the Sea Goat, Aquarius, the Water Carrier, and Pisces, the Fish.  The giant sea monster Cetus rises under Pisces.

Moon Phases in October 2011:
First Quarter October 3, 10:15 pm
Full October 11, 9:06 pm
Last Quarter October 19, 10:31 am
New October 26, 2:56 pm

Saturday, October 8, is our annual Astronomy Day at the George Observatory.

First Light
Creative Commons License photo credit: Space Ritual

 Come join us anytime from 3 to 10 pm.  On Astronomy Day, it is free to look through even the main domes at George.  Before dusk, we will have solar observing, Challenger Center simulations, outdoor and indoor presentations (beginning at 4) and many other activities! On most clear Saturday nights at the George Observatory, you can hear me do live star tours on the observation deck with a green laser pointer.  If you’re there, listen for my announcement.