October 2007 astronomy events

October 2007 astronomy events

As October starts, Mercury is making a retreat into the sun's glare. You may be able to find the messenger very low in the evening sky at sunset. Binoculars or a telescope will help. Jupiter's getting lower in the southwest for northern hemisphere observers, the northwest for those in the southern hemisphere. Find Jupiter north of Antares and the head of Scorpio.

Mars is a late evening riser at the feet of Gemini. The red planet slides up the leg of Castor (the name of both the twin and the star in his head) this month.

In the morning skies, Venus is above Saturn at the start of the month. These two planets form the base of an isosceles triangle with the star Regulus at its apex on the 3rd. The waning crescent moon swings by on the 7th. Venus is closing in on Regulus and Saturn fast. Venus and Saturn are both below Regulus about a third of the way into the month. Venus actually drops below Saturn around the middle of October. The speed with which Venus passes by Saturn is reflective of its relative speed and proximity to Earth. Saturn is so far away and moving so slowly, it's not leaving the patch of sky where we see Leo for a long time. Venus is much closer and quicker, however, and flits across the stellar background.

A series of monthly occultations of Antares by the moon began in late 2005 and will continue until early 2010. This month's occultation will be visible from southern South America and the far southern Atlantic and Indian oceans.

Nights are getting noticeable longer in the northern hemisphere and noticeably shorter south of the equator.

The Orionid meteor shower peaks around October 21st. Its radiant is high in the sky--near the meridian--at moonset early in the morning around this date. That leaves a few hours of potentially good viewing, that is, if the meteor shower puts on a good show this year. Up to 20 meteors may be seen per hour in the northern hemisphere with this shower. Southern hemisphere observers often report up to 40.

On and around the 22nd, the four inner planets (Mercury, Venus, Earth, Mars) will be grouped together in a diamond formation on one side of the sun. That's not the kind of thing earthbound observers can see, but some people like to know about various planetary alignments.

October 4th is the 50th anniversary of the Soviet Union's Sputnik I launch. Sputnik orbited the earth every 96 minutes or so and transmitted radio signals for three weeks to everyone with a capable receiver below. Its power cells died, but the satellite remained visible until it reentered the atmosphere January 4, 1958. Sputnik's launch started the so-called space race between the United States of America and the Soviet Union. If you're out stargazing on October 4th and see a little dot moving across the sky, think about how unusual-and for some, disturbing--the sight was exactly 50 years ago.