This is the Dudley Observatory Skywatch Line for Wednesday, December 9th and Thursday, December 10th written by Louis Suarato
The 3% illuminated, waning crescent Moon sets at 3:15 Wednesday afternoon, and will reappear as a 1% illuminated, razor thin crescent Moon at 5:54 Thursday morning. Saturn rises 15 minutes later, but both will be a challenge to see. The New Moon occurs at 5:29 a.m. Friday.
The Big Dipper asterism in the constellation Ursa Major is parallel to, and low on the northern horizon after Wednesday’s sunset. Throughout the night, the Dipper will climb up the sky, as if scooping up a sea of stars. By midnight, the Big Dipper will be tipped straight up on its handle, perpendicular to the northeastern horizon. As the Big Dipper is rising in the sky, the brightest star in the sky, Sirius moves from east to south. To the east of Sirius, a line of no fewer than 20 open clusters escort Canis Major’s brightest star. The open clusters range from NGC 2301 and 2232 in Monoceros, the constellation to the upper left of Sirius, to M93 and NGC 2527 in the constellation Puppis, to the lower left of Sirius. Another open star cluster, M41, is four degrees below Sirius. M41 was discovered by Giovanni Batista Hodierna before 1654. M41 contains approximately 100 stars and is the size of the full Moon. This open star cluster is estimated to be about 190 million years old and is 2,300 light-years away. According to Robert Burnham, Jr., “M41 is a beautiful object in low power instruments…There is a bright reddish star near the center; many of other stars seem to be arranged in curving rows or groups..”.
You’ll have to stay up late, and into the early morning hours, to see the naked eye visible planets. Jupiter is first, as it clears the eastern horizon around midnight. Jupiter’s moon, Europa, begins its transit at 15 minutes past midnight, followed by its shadow 19 minutes later. The Great Red Spot transits 2 minutes after Europa’s shadow. Mars appears at 2 a.m. in the constellation Virgo, followed by Venus an hour and 40 minutes later. Comet C/2013 US10 Catalina is now to Venus’ upper left, less than a degree from Virgo’s star, Syrma.