This is the Dudley Observatory Skywatch Line for Wednesday, August 1st, and Thursday, August 2nd, written by Louis Suarato.
The Moon sets at 10:17 a.m., and rises at 10:58 p.m., Wednesday, as a 75% illuminated, waning gibbous Moon. At 9:20 p.m., Mars, above the southeastern horizon, and Venus, above the western horizon, are at the same altitude of 7.5 degrees. Although Mars is at its brightest, outshining Jupiter, Venus is still brighter by about 2 magnitudes. Jupiter shines at magnitude -2.10 between the two, about 25 degrees above the southwestern horizon. Saturn can be found about 20 degrees over the south-southeastern horizon, in the stream of stars of the Milky Way representing the steam in the Teapot asterism in Sagittarius. Saturn’s ring-tilt is almost at its maximum of 26.5 degrees.
Aim your telescope a few degrees above Saturn to begin a tour of a string of deep sky objects within the Milky Way above Sagittarius. The first object you’ll find is the Sagittarius Star Cluster, or M24. When you view the stars within M24, you are looking at the stars comprising the Sagittarius-Carina arms of the Milky Way Galaxy. M24 is flanked by open star cluster M23, and M25. The stars within M23 are estimated to be approximately 220 million years old, making this one of the oldest known star clusters in the galaxy. M25 can be found 3.5 degrees to the west of the Sagittarius Star Cloud, M24. At magnitude 4.6, M25 can be seen with the naked eye, but binoculars, or small telescopes will provide more detail of the thousands of young, blue stars within this open cluster.
August 1st is the 200th anniversary of the birth of American astronomer Maria Mitchell. Born in Nantucket, Massachusetts in 1818, Mitchell learned about astronomy from her father at an early age, assisting him determine the exact moment of an annular eclipse. At age 14, Mitchell was calculating navigational routes for local whalers. On October 1, 1847, Mitchell discovered Comet c/1847 T1, also known as Miss Mitchell’s Comet. In 1865, Mitchell and her father moved to Poughkeepsie, NY where she became one of the first professors of Vassar College. At Vassar, she worked with the observatory’s 12 inch telescope, the third largest in the United States at the time. Maria Mitchell also co-founded the Association for the Advancement of Women in the late 1800’s with the goal to improve women’s rights.