Skywatch Line for Friday, July 7, through Sunday, July 9, 2023
This is Dudley Observatory’s Skywatch Line for Friday, July 7, through Sunday, July 9, written by Sam Salem.
On Friday, Sun rises at 5:24am and sets at 8:36pm; Moon sets at 10:17am and rises at 11:49pm.
On Friday and Saturday mornings, the Moon will pass by Saturn. Catch the Moon and Saturn before midnight and watch them move across the sky until dawn. Saturn is racing toward its opposition next month when it will be at its best for the year and visible all night. Saturn shines in the southeast before dawn near the Water Jar asterism in the constellation Aquarius the Water Bearer. Saturn rises before midnight at the beginning of July and before 10 p.m. by month’s end.
Mars sits upper left of Venus in twilight on Friday. Mars sits less than 2° from Regulus, the brightest star in the constellation of Leo, that night. On Sunday evening, bright Venus will lie below the much fainter Mars and Regulus, the brightest star in Leo the Lion. The trio will fit within a 5-degree field. Start looking about 30-45 minutes after sunset. Mars and Regulus will get as close as 0.7 degrees apart, a little more than the width of a full Moon, that evening. Mars and Regulus will still be very close again the next evening. Mars will set around 10:30 p.m. Mars continues to fade and is only a bit brighter than 2nd magnitude stars.
Venus and Mars will be within 3.6 degrees of each other at the beginning of the month, then move apart. Bright Venus will dominate the western sky after sunset in July but will sink lower each day. Venus will reach greatest brilliancy on Friday when it shines at -4.7 magnitude. Venus will be ending its evening dominance at the end of July. Check out Venus in binoculars. The closer Venus gets to Earth, its angular size will grow. Also, it becomes a thinner crescent. When Venus is near its greatest brilliancy, it’s easiest to spot shining out from a blue sky. Venus is currently an evening object, so you can find it before sunset as soon as you can block out the Sun before it sets. Later in the month, around the evenings of July 19 and 20, the crescent Moon will pass close to Venus.
Jupiter is now the brightest object in the morning sky, except the Moon. At the beginning of July, Jupiter rises about 2 a.m. in the east and lies in the zodiacal constellation Aries the Ram. By the end of July, it’ll rise around midnight.
Look for Antares, or Alpha-Scorpii, the brightest star in the zodiacal constellation of Scorpius in the south. The head of the constellation of Scorpius, the near-vertical row of three stars upper right of Antares, stands due south right after dark. The top star of the row is Beta Scorpii, or Graffias, a fine double star for telescope with 13 arcseconds separation and magnitudes 2.8 and 5.0. Just 1° below it is the very wide naked-eye pair Omega1 and Omega2 Scorpii. They are not quite vertical. They’re 4th magnitude and a wide ¼° apart. Binoculars show their slight color difference. Upper left of Beta by 1.6° is Nu Scorpii, separation 41 arc-seconds, magnitudes 3.8 and 6.5. A telescope with a high power in excellent seeing reveals Nu’s brighter component itself to be a close binary, separation 2 arcseconds, magnitudes 4.0 and 5.3, aligned almost north-south.