Skywatch Line for Monday and Tuesday, October 24th and 25th, 2016

This is the Skywatch Line for Monday and Tuesday, October 24th and 25th.

The Sun sets at 5:58 PM; night falls at 7:33. Dawn breaks at 5:46 AM and ends with sunrise at 7:21.

The darkening sky displays five planets. Venus is the brightest, but also the most difficult, only 9 degrees above the southwestern horizon. It blazes with minus 4 magnitude, appears about 80 percent illuminated, and about 13 arc seconds in size. The planet rises higher daily. Tuesday evening, Venus lies 3 degrees above Antares, the red star that marks the Scorpion’s heart. Venus sets at 7:35.

Six-and-a-half degrees east of Venus is Saturn, 14 degrees high. It glows at 0.5 magnitude in Ophiuchus; its white color makes identification easy. Its ring system is still worthwhile viewing. Saturn sets at 8:10.

Mars is further from Saturn, 35 degrees away. Now in Sagittarius, the Red Planet shines at 0.3 magnitude and appears about 86 percent lit in our telescopes. It appears about 22 degrees high in the South. Mars sets at 10:30 PM.

By nightfall, Neptune, in Aquarius, is about 32 degrees high. It still appears about two degrees from the star Hydor (Lambda Aquarii) as a tiny blue-green ball. Neptune is best observed at 9:25 PM, when it is highest, and sets at 2:51 AM. Uranus, in Pisces, is a bit brighter and larger and is best seen at Midnight and stays up all night. Both planets require detailed finder charts, found in various astronomy media.

The 25 day-old Moon rises at 2:14 AM on Tuesday, and 3:15 AM on Wednesday. The Moon blazes at minus 7.9 magnitude in Leo, only four degrees from the star Regulus, the brightest star in Leo. Wednesday sees a slimmer and slightly dimmer Moon near the Lion’s hind legs.

Jupiter rises at 5:24 AM, shortly before first light. It lies in Virgo and about one degree from the bright star Porrima. Jupiter is too low for useful observation in the rapidly brightening sky.

Before Dawn, the important, but dim, constellation Cancer lies bracketed between much brighter Gemini, Leo, and Hydra. The constellation itself is ancient, part of the original Mesopotamian zodiac. The first day of summer, this year on June 20, was the Sun’s highest point of the year. In ancient Greece, this event took place in the constellation of Cancer. Since Cancer is located on the ecliptic, visits by the Sun, Moon and planets are common.

Cancer is an unusual constellation; its brightest feature is not a star, but a cluster of stars. If you live away from city lights, the first thing you see is a hazy patch in the middle of the constellation. This is M-44, the Beehive Cluster. When observed in binoculars or low power telescope, it resolves into hundreds of stars. These are born out of a common gas cloud and are found in the spiral arms of our Milky Way galaxy.

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