This is the Dudley Observatory Skywatch Line for Wednesday, January 10th, and Thursday, January 11th, written by Louis Suarato.
The 33% illuminated, waning crescent Moon sets at 12:35 p.m. Wednesday. The Moon returns in the constellation Libra as a thinner crescent at 2:26 a.m., 4 degrees north of Jupiter, and 5 degrees north of Mars. This cosmic triangle will be followed by a close conjunction of Mercury and Saturn. Look low over the southeastern horizon around 6:30 a.m. to see the two planets 2 degrees apart. In addition to a clear horizon, you may require binoculars to see Mercury and Saturn rise before the Sun.
On October 2, 2017, while using the University of Hawaii’s telescopes to search for Near-Earth Asteroids, astronomer Ari Heinze discovered Comet C/2017 T1 Heinze. At the time, the comet was 18th magnitude in the constellation Hydra. On January 6th, the comet came closest to Earth. It is estimated to be 8.8 magnitude at its peak. Look for Comet Heinze in the moonless sky in the constellation Cassiopeia. It is now circumpolar, and will be visible all night over our region. The coordinates for Wednesday night are right ascension: 23h 39m 04s, declination: +57°55’34”. Using binoculars, look 5 degrees past the star, Caph, at Cassiopeia’s deeper V side for the comet.
If you look to the west of the star Caph, you’ll find open star cluster NGC 7789. This star cluster is also known as Mel 245, Caroline’s Rose Cluster, Ghost Cluster, Star Mist Cluster, Herschel’s Spiral Cluster, Crab Cluster, and Screaming Skull Cluster. NGC 7789 was discovered by Caroline Herschel in 1789. This 6.7 magnitude star cluster contains loops of stars, and dust lanes that give it the appearance of rose petals. Estimated to have 1.6 billion young stars, NGC 7789 is 8,000 light-years away. Caroline’s Rose is 50 light-years across, and spans about a half of a degree in the sky.