Jupiter dominates October night sky, joined by Saturn, Venus and Mercury

2009-10-01 / Home

For October, the Moon will be full moon on the 4th, this is the "Harvest Moon", closest to the Autumnal Equinox in late September. The first two weeks find the moon waning in the morning sky. Halloween finds the moon just past first quarter on the 26th, so the waxing gibbous moon and Jupiter in the south make for sharing telescopic views with the trickor treaters in the evening twilight.

Jupiter dominates the southern sky just above the tail of Capricornus the sea goat. Any small scope will reveal what Galileo marveled at 400 years ago this month; four large moons, all bigger or similar to ours in size, orbit it in a line along Jupiter's equator.

Venus dominates the morning now, and plays an interesting game of tag with Mercury and Saturn in the dawn. On October 1, Venus is above much fainter Mercury, which in turn is above faint Saturn 45 minutes before sunrise.

Mercury passes Saturn very closely on October 8, and the most striking grouping is on October 10, with the three planets equally spaced and Saturn in the middle. Venus passes Saturn on October 13, and the waning crescent Moon joins the club on October 16, passing just south of Venus, and by Mercury (but very difficult to spot in the dawn) on October 17. These fine groupings are easy to capture with any tripod mounted digital camera in nightshot mode, so see if you can capture the fine sequence of planetary "dancing in the dawn".

The constellation Cassiopeia makes a striking W, rising in the NE as the Big Dipper sets in the NW. Polaris lies about midway between them. She contains many nice star clusters for binocular users in her outer arm of our Milky Way, extending to the NE now.

Her daughter, Andromeda, starts with the NE corner star of Pegasus'' Square, and goes NE with two more bright stars in a row.

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