Skywatch Line for Monday and Tuesday March 27th, and 28th, 2023

This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday March 27th, and 28th, written by Joe Slomka.

The Sun sets at 7:16 PM; night falls at 8:52. Dawn begins at 5:09 AM and ends with the Sun rising at 6:45.

The Moon is found in the West on both nights. Monday’s Moon, in Taurus, rises at 9:59 AM, 30 arc-minutes in size, 40% illuminated, 52 degrees high at 9 PM and sets at 2:20 AM, Tuesday. Tuesday’s First Quarter Moon migrates to Gemini, now 50% lit, 29 arc-minutes, 62 degrees high at 9 PM and sets at 3:13 AM on Wednesday. Tuesday, Mars lies about 2 degrees below the Moon.

If you have an unobstructed western horizon, you could see Jupiter and Mercury low at about 30 minutes after Sunset. Mercury is ascending while Jupiter sinks. Also, Dusk reveals Mars, the Moon, Uranus and Venus also in the West. It is also possible to see brilliant Sirius (the Dog Star) low in the Southwest before Sunset.

Western Aries houses both Venus and Uranus. Venus hugs the horizon. It blazes with minus 4th magnitude, 13 arc-seconds, 5 degrees high at 9 PM and sets at 10:19 PM. Much smaller Uranus lies 4° from Venus on Monday and 1° on Tuesday; it shines with 5th magnitude, 3 arc-seconds, 8 degrees high at 9 PM and sets at 10:33.

As mentioned above, the Moon and Mars share Gemini on Tuesday night. Mars continues to shrink in brightness and apparent size, now zero magnitude, 6 arc-seconds, 90% lit, 48 degrees high at 9 PM and sets at 2:25 AM. Dwarf Planet Ceres is found in the constellation Coma Berenices; it lies about 6 degrees behind Leo’s tail (Denebola), it glows with 7th magnitude, 0.7 arc-seconds, rises at 5:05 PM, 41 degrees high at 9 PM, 63° highest at 12:13 AM and sets at 7:15.

Saturn, in Eastern Aquarius, is the only easy planet to see in the Dawn sky. It twinkles with 1st magnitude, 15 arc-seconds, it rises at 5:40 AM and is 12 degrees high at 6 AM.

With the Moon and Mars in Gemini, let us examine this constellation. Gemini is ancient. The constellation was recognized as “Twins” by many cultures. Castor and Pollux, in Greek legends, were the sons of a mortal and Zeus. They crewed the legendary vessel Argo. Ancient sailors prayed to them for a safe voyage. The phrase “By Jiminy” harks back to an ancient oath. The stars are approximately equally bright. In 1803, Herschel discovered Castor to be a binary – two stars orbiting each other. This was the first binary to be discovered. Now, astronomers know Castor to be a six-member stellar system.

Pollux is even more interesting. It is the brightest star to have a planet. The planet is about three times Jupiter’s mass and takes 590 days to orbit Pollux. Pollux is slightly brighter then Castor. Pollux has ceased fusing hydrogen and in the beginning stages of becoming a giant star. Castor and Pollux are about 18 light years apart, with Pollux around 34 light years from Earth.

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