Skywatch Line for Monday and Tuesday, February 12th and 13th, 2018

This is the Skywatch Line for Monday and Tuesday, February 12th and 13th.

The Sun sets at 5:23 PM; night falls at 6:56. Dawn begins at 5:20 AM and ends with the Sun rising at 6:55.

The evening sky lacks easily visible planets. Eighth magnitude Neptune still inhabits Aquarius, near the brighter star Hydor. Binoculars or telescope may be needed to locate the dim planet in the setting Sun’s glare; Neptune sets at 6:58 PM. Uranus is still in Pisces, near the star Mu Piscium. The 6th magnitude planet sets at 10:35 PM. Dwarf Planet 1Ceres should be visible after nightfall. It is located in Cancer, shines at 7th magnitude and appears as a tiny 0.7 arc-second in size. All three require detailed finder charts from various astronomical media.

Jupiter rises at about 12:47 AM in Libra. It shines at minus 2nd magnitude about 30 degrees high in the southeast sky and is best seen at 5:42 AM. Telescopic observers can see the Jovian moon Europa early Tuesday morning. Its shadow leaves the planet’s face at 1:49 AM; Europa itself begins its transit across Jupiter at 2:02 AM and exits Jupiter at 4:13 AM.

Mars rises in Ophiuchus at about 2:22 AM. It shines at 1st magnitude, is 6 arc-seconds is size, appears about 90 percent illuminated and lies about 18 degrees below Jupiter. By Dawn, Mars is high enough to be observed and noted that it lies about 5 degrees from similar looking Antares.

Saturn rises about 25 degrees below Mars. The Ringed Planet, in Sagittarius, shines at 0.6 magnitude and is about 9 degrees above the southeastern horizon, having risen at 4:14 AM. While Saturn rises earlier and higher daily, it still is too low to appreciate its beautiful ring system.

The Moon barely exists in the twilight sky. Tuesday, it rises in Sagittarius at 5:34 AM, blazes at minus 3.3 magnitude but is only about 5 percent lit. Wednesday finds it rising in Capricornus at 6:14 AM, glowing at 0.5 magnitude, about 1 degree high and about 2 percent lit, making Wednesday’s Moon our challenge object.

We mentioned that Mars and the bright star Antares are about 5 degrees apart. This is an excellent time to compare and contrast the two. Both objects exhibit a reddish orange color. However, Mars is red because its surface consists of rusty soil; Antares is a supergiant star, which is much brighter than our Sun but also cooler. It is huge; if substituted for the Sun, it would extend beyond Mars. It is also burning its fuel at a far greater rate than our Sun. In the distant future, Antares will explode as a Supernova. Because of the similar colors, ancient peoples thought them as rivals. “Antares” actually translates as the “rival of Ares,” the Greek version of the Roman war-god Mars.

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