Title: September Skywatch Highlights
Location: Hawaiian Islands
Date / Time: September 2012
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. Currently: glorious bands of Milky Way stars illuminate our dark Hawaiian sky with a rich, "milky" haze. High in the northern sky, the three bright stars of the Summer Triangle are easy to spot: ALTAIR, in Aquila the Eagle; VEGA, in Lyra the Harp; & DENEB, in Cygnus the Swan. Scorpius, the giant Scorpion, & Sagittarius, the Archer, display boldly toward the southwest, as Andromeda, with the great Andromeda galaxy, rises from the east. SATURN lies about 10-degrees high in the west-southwest, an hour after sunset, in early September. The ringed planet appears in the constellation Virgo, just a few degrees above (NE) of Spica, Virgo's brightest star. Saturn, at magnitude 0.77, and Spica, (mag.0.96), are the 2 brightest points of light in this part of the sky. Notice Saturn's golden hue, compared to blue-white Spica. With each passing day, the star & planet sink lower in the sky. By the end of the month, Spica will be gone, & Saturn will set a half hour after dusk. Saturn will pass behind the Sun in late October & return to view before dawn a few weeks later. In early September Saturn's glorious ring system tilts 14-degrees to our line of sight from Earth. When Saturn returns to view in November, the rings will tilt 18-degrees & appear even more spectacular. MARS appears approximately 10-degrees to the left (east) of Saturn early in the month, crossing from Virgo into Libra on Sept. 3rd. The Red Planet, at magnitude 1.2, is noticeably fainter than Saturn, and shines with a distinctive ruddy glow. Mars moves rapidly eastward, traveling thru most of Libra this month, & fading in brightness. Look for the waxing crescent Moon just below Mars on Sept. 18th, and just above Mars on Sept. 19th. VENUS and JUPITER, the brightest points of light in the sky, continue to dazzle in the early hours of predawn. Throughout the month, look east from 3:30AM thru daybreak (around 5:15AM). VENUS, at magnitude minus -4.3, blazes like a beacon, low in the eastern sky. On Sept. 12th, look for a stunning alignment: Venus, in Cancer, 3-degrees to the right (SW) of the Beehive star cluster (M44), with a crescent Moon 4-degrees to the right (SW) of Venus. (The Beehive shines at 4th magnitude, & it helps to have binoculars to spot it). Look for brilliant JUPITER high above Venus, shining at magnitude minus -2.3. Jupiter, in Taurus, appears less than 10-degrees NE of the Hyades star cluster all month. At the start of September, Jupiter rises at midnight and is nearly halfway up in the east when Venus rises at 3:30AM. By the end of the month, Jupiter rises by 10:20PM, and is about 2/3 of the way up in the east by the time Venus rises at 3:30AM. With a small telescope or good binoculars, you can view Jupiter's 4 bright Galilean moons in their ever-changing configurations. Larger scopes will reveal Jupiter's dark equatorial belts, (one on either side of a brighter equatorial zone), the giant red spot, & other dynamic surface features. 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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