Skywatch Line for Monday and Tuesday, February 15 and 16, 2016

This is the Skywatch Line for Monday and Tuesday, February 15th and 16th.

The Sun sets at 5:26 PM; night falls at 7:01. Dawn breaks at 5:17 AM and ends with the Sun rising at 6:52.

The Moon turned “First Quarter” early Monday morning; civil twilight finds it high in the southern sky. The Moon appears about 57 percent illuminated Monday night, and 68 percent on Tuesday night. It inhabits Taurus on both nights. The Moon sets before Astronomical Dawn.

Uranus is the sole planet visible. In Pisces, it is a sixth magnitude blue-green speck. Asteroid 4Vesta is an eighth magnitude pinpoint six-and-a-half degrees away. Both set by 10 PM and require detailed charts from astronomy magazines, websites and apps to find them.

Jupiter rises about 7:21 PM, and, by 9 PM, is moderately high in the eastern sky. It shines at minus 2.4 magnitude near Leo’s hind leg. While visible to the naked eye and binoculars, Jupiter is best studied with a telescope. On Tuesday night, the observer can see the Great Red Spot, a giant storm, at 8:49 PM and at 2:36 AM on Wednesday. Observers can also see Jovian moon Ganymede cast its shadow on Jupiter’s cloud tops at 10:57 PM on Tuesday, followed by Ganymede itself at 12:58 AM Wednesday. The shadow exits the planet at 2:28 AM Wednesday, trailed by Ganymede itself at 4:06 AM. Jupiter sets during daylight.

Seventh magnitude Comet Catalina is still visible in our skies. It lies in the obscure constellation Camelopardalis, about 22 degrees above Polaris, the North Star. Due to its proximity to Polaris, the comet does not rise or set, but circles Polaris in 24 hours. Again, reference to astronomical media will produce finder charts.

Astronomical Dawn sees Jupiter moderately low in the southern sky. Mars rises about 12:35 AM in Libra. It appears as a red dot in the constellation’s middle. At 0.6 magnitude and 90 percent illuminated, Mars slowly gains in brightness and size; at 5:33 AM, it is best situated for observation. Saturn follows by rising at 2:28 AM in Ophiuchus. At magnitude 0.5, Saturn outshines the dim constellation. Venus, in Sagittarius, rises at 5:34 AM and blazes at minus four magnitude. In binoculars or small telescope, it appears about 88 percent illuminated and shrinks slightly in size. Mercury brings up the rear again. It rises at 5:50 AM, four degrees below Venus. At four degrees altitude, Mercury, at minus 0.1 magnitude, is best seen by first finding Venus and looking one binocular field down. An unobstructed eastern horizon also helps.

Most astronomers conduct their research at ground-based observatories. Some also use space-based telescopes, like Hubble, or rovers on other planets. NASA has SOPHIA, a telescope that rides in a specially modified Boeing 747. The Albany Area Amateur Astronomers have their monthly meeting on Thursday, February 18th at 7:30 PM. Dudley Observatory astronomer Dr. Valerie Rapson will describe her recent observing session aboard that aircraft. As usual, all club events are free and the public is welcome to hear her talk.

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