This is Dudley Observatory’s Skywatch Line for Friday, June 19, through Sunday, June 21, written by Sam Salem.
On Friday, Sun rises at 5:17am and sets at 8:37pm; Moon rises at 4:06am and sets at 7:13pm. At its new phase on Sunday, at 2:41 a.m., the Moon will be travelling between the Earth and the Sun, for an annular solar eclipse. The partial eclipse will not be visible from the US, but can be seen throughout eastern Africa, southern Europe and the Middle East, most of Asia and Southeast Asia. This new Moon will occur 6.2 days past apogee, resulting in a thin-ringed annular solar eclipse visible across central Africa and southern Asia.
For about an hour before sunrise on Friday, the very slim crescent of the old Moon will sit very close to the bright planet Venus. Look for the pair just above the east-northeastern horizon. The Moon and Venus will fit together in the field of view of binoculars and backyard telescopes.
On Saturday, the June solstice arrives at 5:44 p.m. This is when the Sun reaches its northernmost declination in Earth’s sky and begins its six-month return southward. Summer begins in the Northern Hemisphere, winter in the Southern Hemisphere. For us northerners, this is the longest day and shortest night of the year. On Saturday, the day is 15 hours, 20 minutes, and 20 seconds long (Schenectady latitude). In terms of daylight, this day is 6 hours, 19 minutes longer than on December Solstice. It’s also the day when the midday Sun passes the closest it ever can to being straight overhead, and thus when your shadow becomes the shortest it can ever be at your location.
Mercury is ending its apparition in evening twilight. The little planet is fading fast, while dropping out of view deep into bright twilight. Venus is very deep in the glow of sunrise. Venus is on its way up to becoming the bright Morning Star of summer and fall in a few days. Mars, at magnitude –0.2, rises in the east around 1 a.m., shining bright orange at the constellations Aquarius-Cetus border. By the first light of dawn Mars is fairly high in the southeast for telescopic viewing. This week Mars grows from 10 to 11 arc-seconds in apparent diameter. In a telescope Mars is as gibbous as it gets, 84% sunlit.
Jupiter and Saturn rise in late evening. Jupiter rises first, a few minutes after 10pm, then dimmer Saturn following about 20 minutes behind. They’re 5 degrees apart. Look for the Sagittarius Teapot resting upright farther to Jupiter’s right. The two giant planets shine at their highest and telescopic best in the hour or so before the beginning of dawn. They straddle the border of Sagittarius and Capricornus.