Skywatch Line for Friday, April 4, through Sunday, April 6, written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, April 4, through Sunday, April 6, written by Sam Salem.
On Friday, Sun rises at 6:32am and sets at 7:25pm; Moon sets at 2:24am and rises at 10:45am.
On Friday evening, the first quarter Moon will lie below a line formed by Mars and the twin stars of Gemini, Castor and Pollux. Procyon, the brightest star in Canis Minor, sits nearby. As the night progresses and the sky turns westward, the arrangement will rotate clockwise. The first quarter Moon rises around noon and sets around midnight.
On Saturday, Mars and the Moon will be 3° or 4° apart.
The Lunar X and V are claire-obscure effects. They are created by the way light and shadow interact with the lunar surface. They are best seen around the first quarter Moon phase, specifically for a few hours around the terminator. They are most striking when they are visible on the shadow side of the terminator. The X appears as the lunar dawn approaches, and the V appears further north along the terminator. The X is visible for a few hours before the first quarter, slightly below the lunar terminator. The illusion of Lunar X is created by sunlight falling on the rims/ridges between the craters La Caille, Blanchini, and Purbach. The V is formed by light illuminating crater Ukert, along with several smaller craters.
Venus has passed its inferior conjunction and is now emerging into dawn view. Look for it very low due east starting about 30 minutes before sunrise. Binocular will help. Venus gets higher, brighter, and easier every day. It’s in its thin-crescent phase in a telescope or steadily braced binoculars. Post-conjunction, the bulge of the crescent now faces lower left toward the Sun.
Mars, at magnitude +0.4 near the heads of Gemini, comes into view evening twilight as a steady yellow-orange spark very high toward the south, almost overhead. It continues to fade as it shrinks into the distance, looking ever more like its neighbors Pollux and Castor. The three dots form an arc that gradually straightens out day by day. They’ll form a straight line on Thursday, April 10th.
Jupiter shines bright white, at magnitude –2.1, high in the west these evenings, in the constellation of Taurus, 38° lower right of Mars along the ecliptic. Jupiter shines midway between Aldebaran and Beta Tauri (El Nath). Farther to Jupiter’s lower right you’ll find the Pleiades. Jupiter sets in the west-northwest around midnight.
Coma Berenices is a visible constellation in spring skies that represents the hair of Queen Berenice. The constellation itself is not very bright. You’ll need a dark sky to see most of its stars. Coma Berenices trails the constellation of Leo the Lion, with the Big Dipper high above it and Virgo with bright star Spica below. Instead of going northward from the pointer stars to Polaris, the North Star, go southward instead to find the constellation Leo. In the place where you might see a “puff” at the end of the Lion’s tail, you’ll notice a fuzzy patch not too far away from Denebola. This is the constellation Coma Berenices, or Berenice’s Hair.