Skywatch Line for Friday, March 1, through Sunday, March 3, 2024 written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, March 1, through Sunday, March 3, written by Sam Salem.
On Friday, Sun rises at 6:30am and sets at 5:45pm; Moon sets at 8:55am.
On Saturday and Sunday mornings, the Moon will be near the bright star Antares in Scorpius the Scorpion. The last-quarter Moon occurs at 10:23 am Saturday morning.
Venus, at magnitude –3.9, rises in the southeast while dawn is brightening. Try to locate it very low, 40 or 30 minutes before sunrise.
Jupiter, at magnitude –2.2 in the constellation of Aries, is the bright white dot high in the west in twilight, lower as evening grows later. It sets around 11 p.m. In a telescope, Jupiter has shrunk to only 36 arcseconds wide. Jupiter is now midway between Hamal (Alpha Arietis) a fist-width to its right, and Menkar (Alpha Ceti) a fist-width to its left. The two stars are magnitudes 2.0 and 2.5, respectively.
The bright star Capella is almost overhead and will lead you to the constellation Auriga the Charioteer. To be sure you’ve found Capella, look for a little triangle of stars nearby. Capella is sometimes called the Goat Star, and the little triangle of stars is an asterism called The Kids. After finding Capella, you can trace out the rest of this pentagon-shaped group of stars. Under dark skies, use binoculars to see the three fine Messier objects, M36, M37 and M38. They are open star clusters with distinct personalities when viewed with magnification.
Sirius blazes high in the south on the meridian by about 8 p.m. Using binoculars or a scope at low power, examine the spot 4° south of it, directly below it when on the meridian. Four degrees is somewhat less than the width of a typical binocular’s or finder-scope’s field of view. Look for a little patch of speckly gray haze. That’s the open star cluster M41. It’s about 2,300 light-years away. Its total magnitude adds up to 5.0.
Sirius, by comparison, is only 8.6 light-years away. Being so near, it shines some 400 times brighter than the entire cluster.
Look east after dusk for the constellation Leo the Lion already climbing well up the sky. Its brightest star is Regulus. The Sickle of Leo, about a fist and a half tall, extends upper left from there.
These moonless nights are a fine time to collect some telescopic triple stars. If you had to name one triple star of the winter sky it might be Beta (β) Monocerotis, a trio of hot B-type stars shaped like a series of knots in a kite’s tail. Few threesomes are as bright and exquisite as this gem. William Herschel called it “one of the most beautiful sights in the heavens.” Double stars are gorgeous enough, but adding a third star makes us wonder exactly who is orbiting whom. While triples are less common than doubles, their members continue to orbit the system’s center of mass. Often, two of the stars will form a closer, orbiting pair circled at a distance by the third member, a stable arrangement called hierarchical. Beta Monocerotis is likely a hierarchical system with the bright A star in a stable orbit around the tighter B-C pair. Beta Monocerotis lies in the southwestern
part of the faint constellation Monoceros the Unicorn, less than 4° from that star group’s border with Orion. Use a star chart to help you find it.