Skywatch Line for Friday, June 9, through Sunday, June 11, 2023
This is Dudley Observatory’s Skywatch Line for Friday, June 9, through Sunday, June 11, written by Sam Salem.
On Friday, Sun rises at 5:17am and sets at 8:32pm; Moon rises at 12:56am and sets at 11:14am. Last-quarter Moon occurs at 3:31pm on Saturday. The Moon rises on Saturday night around 2am, lower right of the Great Square of Pegasus and lower left of Saturn.
Saturn rises around 1:00am on Saturday morning, followed later by the Moon, nearly last quarter, 6° or 7° to Saturn’s lower left. By early dawn the Moon and Saturn are well up in the southeast.
Mercury is deep in the glow of sunrise, brightening to magnitude –0.3. Use binoculars to locate it well to the lower left of brighter Jupiter. They’re moving apart, to 22° of separation on Saturday morning.
Venus, at magnitude –4.4 in Cancer, is the brilliant “Evening Star” in the west from twilight into late evening. It’s not quite as high in the dusk as it was a couple weeks ago, but it doesn’t set until about 1½ hours after full dark. Venus starts to move farther out of line with Castor and Pollux every day. In a telescope Venus is a dazzling little half-Moon shape, just starting to show signs of turning into a fat crescent. It enlarges a little every day while waning in phase. Venus will become a bigger, thinning crescent dropping lower until it’s lost from sight in mid- to late July.
Mars, at magnitude 1.6 in Cancer, glows weakly to the upper left of Venus, by a slowly shrinking distance, 8° by Friday. That’s not quite a fist at arm’s length. Mars and Venus will reach a minimum separation of 3.6° on June 30th, then they’ll start to draw apart again as Venus plunges down toward the sunset.
Jupiter, at magnitude –2.1 in Aries, is low in the east as dawn brightens. It might be easiest to see about 60 to 45 minutes before sunrise.
Spica is straight below Arcturus not long after dark. Half as far to Spica’s lower right is the compact four-star pattern of Corvus, the springtime Crow. Catch Corvus before it sinks too low and departs from the evening sky until next year.
Johann Gottfried Galle was born on June 9, 1812. The German Astronomer was the first to observe the planet Neptune on September 23, 1846. Neptune’s existence had been predicted in the calculations of Le Verrier. The French Astronomer Le Verrier had written to Galle asking him to search for the ‘new planet’ at a predicted location. Galle was then a member of the staff of the Berlin Observatory and had discovered three comets. In 1838, while assistant to Johann Franz Encke, Galle discovered the dark, inner C ring of Saturn at the time of the maximum ring opening. In 1851, Galle became professor of astronomy at Breslau and director of the observatory there. In 1872, he proposed the use of asteroids rather than regular planets for determinations of the solar parallax.