Title: September Skywatch Highlights
Location: Hawaiian Islands
Date / Time: September 2011
Comments: September marks the transition from Summer to Autumn skies. The Autumnal Equinox occurs on Sept. 22nd here in Hawaii. This is the moment when the Sun crosses the celestial equator, marking the change in seasons from summer to fall. On the day of the equinox, the Sun rises exactly in the East, & sets exactly in the West, & periods of day & night are equal (close to 12 hours each). After the equinox, the Sun will appear lower & lower in the sky & the days will grow shorter. SATURN disappears from view by the end of September. The ringed planet will set by 8:30 PM early in the month; with Spica (the brightest star in Virgo) following shortly thereafter. (You'll find Saturn ten degrees to the right of Spica, low in the Western sky at sunset). Saturn & Spica will appear a little lower in the west each night and, by the last week in September, Saturn will be lost in the light of the setting Sun. Dazzling JUPITER certainly lives up to its nickname this month: "The King of Planets." The gas giant rises by 10PM in early Sept., & by 8PM at months end, & reigns until dawn. At magnitude minus -2.7, it appears as the brightest object in our sky (except for the Moon). The brilliant planet spends most of the month tracking eastward across south-central Aries, the Ram. Jupiter will reach opposition in October, so now is a great time for telescopic observing. A small telescope or good binoculars will reveal Jupiter's 4 bright Galilean moons, in their ever-changing configurations. Galileo first saw them nearly 400 years ago with a 1.5-inch telescope of lower quality than any available today. MARS rises in the east around 2:30AM at the start of Sept., at by 2AM at months end. The red planet shines at magnitude 1.4 & has a pale orange glow. Mars starts the month in Gemini, passing just south of 1st magnitude, Pollux, (one of the Gemini twins); then crosses into Cancer the Crab by the 15th. On Sept.30th & Oct.1st look for Mars against the background stars of the magnificent Beehive Cluster (M44). Through binoculars or a wide-field telescope, Mars sits like a red gem in the midst of this beautiful cluster of blue-white stars. VENUS has been lost in the Sun's glow for more than 2 months. It will finally emerge from behind the Sun, & reappear in the evening sky in late September. Look for our brightest planet (magnitude minus-3.9) extremely low in the west, around 6:45PM, beginning on Sept. 20th. You'll need an unobstructed view to the western horizon, & you'll need to look fast, as Venus sets by 7PM in those last ten days of the month. MERCURY reaches western elongation (its greatest angular distance west of the Sun) on Sept. 3rd, & makes an impressive appearance before dawn. During the first week of September, look for the tiny innermost planet, (glowing at magnitude minus-0.3) low in east at around 5AM. Mercury appears in the constellation Leo, & passes 1st magnitude Regulus, Leo's brightest star, in the month's second week. By the 15th, Mercury will brighten to minus-1.2 magnitude, but will appear so close to the horizon that it will be difficult to spot, as it heads back toward the Sun. For a September Hawaiian sky map, visit Bishop Museum Planetarium www.bishopmuseum.org/planetarium (bishopmuseum.org).

Maintained by Roz Reiner - Kauai, Hawaii

 

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