This is Dudley Observatory’s Skywatch Line for Friday, May 22, through Sunday, May 24, written by Sam Salem.
On Friday, Sun rises at 5:26am and sets at 8:19pm, the waxing crescent Moon rises at 5:33am and sets at 8:21pm. New Moon occurs on Friday at 1:39pm.
On Saturday, catch the super-thin crescent Moon, hardly more than a day old very low below Venus and Mercury while twilight is still bright. The waxing crescent Moon will join Mercury and Venus in the west-northwestern sky after sunset on Sunday. Look for the Moon’s slim crescent sitting a fist’s width to the upper left of very bright Venus, with much dimmer Mercury between them.
On Friday, Mercury and Venus are still close together, 1.7 degrees apart. Thereafter they separate again, with Mercury now on top. Mercury fades from magnitude –1.1 to –0.6. Venus, in northern constellation Taurus, is dropping fast now. It shines brightly in the west-northwest in twilight, as it heads down toward its June 3rd conjunction with the Sun. Venus fades from magnitude –4.6 to –4.3 but remains a dazzler. Mercury sets around 10PM and Venus sets a couple of minutes earlier. A little farther above Venus each evening is Beta Tauri, magnitude 1.6. Mercury climbs rapidly up from the horizon day by day to meet it.
Mars, Jupiter, and Saturn shine in the southeast to south before and during early dawn. Jupiter, the brightest, is on the right. Before dawn begins, spot the Sagittarius Teapot off to the lower right of it. Saturn glows pale yellow 4 degrees to Jupiter’s left. Mars, in constellation Aquarius, is much farther, 30 degrees to 35 degrees, to Saturn’s left as dawn begins. It has been slowly brightening and enlarging. In a telescope Mars is now about 8.5 arc-seconds wide, a tiny gibbous disk.
In the southeastern pre-dawn sky on the mornings surrounding Sunday, the west to east orbital motion of the dwarf planet Ceres will carry it a generous palm’s width below, or 7 degrees, to the celestial south of Mars. The asteroid will shine at magnitude 8, much dimmer than Mars’ magnitude 0.1. However, Ceres should be readily visible in binoculars if you use the stars Skat and Tau Aquarii to help you locate it. Skat or Delta Aquarii appears modestly bright in a dark country sky. It’s near on the sky’s dome to a very bright star, Fomalhaut in the constellation Piscis Austrinus, the Southern Fish. If you can see the Great Square of Pegasus and Fomalhaut, they can help you find Skat. Find Skat by first finding the Great Square of Pegasus. Skat is found roughly on a line drawn southward through stars on Square’s west side. It’s between the Great Square and the bright star Fomalhaut.
Less than two binoculars fields to the left of Mars, distant Neptune will be shining with the same intensity as Ceres. Look for that blue planet sitting just a few degrees to the lower left of the star Phi Aquarii.