This is Dudley Observatory’s Skywatch Line for Friday, November 8, through Sunday, November 10, written by Sam Salem.
On Friday, Sun rises at 6:39am and sets at 4:40pm; the waxing gibbous Moon rises at 3:20pm and sets at 2:26am. In early evening on Saturday, look high above the Moon for the Great Square of Pegasus through the moonlight. The Great Square is standing on one corner. The line from its top star through its bottom star points to the Moon.
Friday morning offers a good chance to spot Mars. The planet will be 3 degrees upper left of Spica. If you look low in the east-southeast about an hour before the Sun rises, the first object you’ll see is 1st-magnitude Spica, Virgo the Maiden’s brightest star. Look more closely and you should notice Mars’ ruddy glow to its north, or upper left. Shining at magnitude 1.8, Mars appears half as bright as the star. Spica is distinctly brighter at magnitude 1.0. In the early morning, you might see Spica, but not Mars, with the eye alone. These two worlds will remain close together all week and should easily fit into a single binocular field. Note the contrast of color between blue-white Spica and ruddy Mars.
Brilliant Venus stands out low in the southwest during evening twilight. Venus lies 6 degrees above the horizon a half-hour after sunset and sets few minutes before 6pm. At magnitude –3.8, Venus is the brightest object in the evening sky with the exception of the Moon. On Saturday evening, Venus appears 4 degrees due north, or lower left, of the Scorpion’s brightest star, 1st-magnitude Antares. Binoculars can help you spot the star’s ruddy glow against the twilight background. Jupiter, at magnitude –1.9, lies in southern constellation Ophiuchus. It is the creamy-white dot low in the southwest as twilight fades away. Jupiter lies between Saturn to its upper left and Venus to its lower right, about 20 degrees from each. Jupiter sets few minutes before 7pm and Saturn sets around 8:30pm.
The variable star Algol in constellation Perseus reaches minimum brightness at 2:57am on Saturday morning. If you start watching it early on Friday evening you can see its brightness diminish by 70 percent over the course of about five hours as its magnitude drops from 2.1 to 3.4. This eclipsing binary star runs through a cycle from minimum to maximum and back every 2.87 days. Algol appears nearly overhead around midnight and remains well above the northwestern horizon until dawn.
Mercury will transit the Sun on Monday morning. The entire 5 1/2 hour path across the Sun will be visible across eastern U.S. During that time, Mercury can been seen through telescopes with solar filters as a small black dot crossing the Sun’s face. For our area, first contact of Mercury with the Sun’s disk occurs around 7:36am, Mercury’s shadow exits the Sun’s disk around 1:04pm.
Saturday marks the 85th. birthday of Carl Sagan. Born on November 9 1934, the U.S. astronomer, exobiologist, and writer of popular science books, is best known for his work as a science popularizer and communicator. His best known scientific contribution is research on extraterrestrial life. Sagan assembled the first physical messages sent into space, the Pioneer plaque and the Voyager Golden Record. It’s a universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the now accepted hypothesis that the high surface temperatures of Venus can be attributed to and calculated using the greenhouse effect. Sagan died in December 1996.