Thursday, March 24
Comet Ikeya-Murakami (P/2010 V1) swings past the Sun every 5.4 years. Tonight you’ll find it in the constellation Leo the Lion near the spectacular spiral galaxy NGC 2903. In fact, tomorrow night the comet will lie only ¼° from the galaxy. Tonight, however, train a telescope on Ikeya-Murakami and you’ll see its tail as a slash of light as it turns edge-on to us.

Friday, March 25
The Moon reaches apogee, its farthest point from Earth in any orbit, at 12 p.m. EDT. At that time, our satellite will lie 252,354 miles (406,125 kilometers) from Earth.

Saturn reaches the point in its orbit where it appears stationary from here on Earth. From this date until August 14, Saturn will be moving westward through the stars as Earth, moving faster in its orbit, passes the ringed planet. Astronomers call this apparent (westward) movement retrograde motion. Saturn will resume its normal eastward motion through the stars in mid-August.

Saturday, March 26
One of the sky’s largest asterisms — a recognizable pattern of stars separate from a constellation’s form — occupies center stage after darkness falls on March evenings. To trace the so-called Winter Hexagon, start with southern Orion’s luminary, Rigel. From there, the hexagon makes a clockwise loop. The second stop is brilliant Sirius in Canis Major. Next, pick up Procyon in the faint constellation Canis Minor, then the twins Castor and Pollux in Gemini, followed by Capella in Auriga, Aldebaran in Taurus, and finally back to Rigel.

Sunday, March 27
The variable star Algol in the constellation Perseus reaches minimum brightness at 6:26 A.M. EDT, right around the time the Sun is rising in the east. Take a look for it just before dawn starts to brighten the sky. Algol then shines at magnitude 3.4 where it will remain for a couple of hours before starting to brighten again. If you spot it the following night, you will see it at its maximum — magnitude 2.1.