Monday, March 6
Around 8 p.m. local time, the brightest star in the night sky — Sirius (Alpha Canis Majoris) — lies due south. With a magnitude of –1.46, Sirius triples the apparent light output of Orion’s brightest star, blue-white Rigel (Beta Orionis). The common name Sirius comes from the Greek term for “sparkling” or “scorching.” Richard Hinckley Allen, writing in Star Names and Their Meanings (G. E. Stechert, 1899) attributes this star’s name to the Greek poet Hesiod, who lived in the latter half of the 8th century b.c. Although Sirius ranks number one among stars, both Venus and Jupiter outshine it tonight. Jupiter appears twice as bright, and Venus’ light surpasses that of Sirius by a factor of 16.
Tuesday, March 7
English astronomer Sir John Frederick William Herschel was born on this date in 1792. In 1864, he published the General Catalogue of Nebulae and Clusters, the direct precursor to the New General Catalogue (NGC), which astronomers still use today. After sunset, if your site is dark enough, you can see many objects from the NGC. For example, look toward the region of Orion the Hunter’s sword. Through binoculars, you’ll spot a fuzzy patch of light that is the 1,976th object in the NGC. You may know it better as either M42 or the Orion Nebula.
Wednesday, March 8
The variable star Algol in Perseus reaches minimum brightness tomorrow morning at 4:08 a.m. EST. If you start watching the star this evening, you can see it dim by 70 percent over the course of about 5 hours. (Astronomers would say its brightness drops from magnitude 2.1 to 3.4.) This eclipsing binary runs through a cycle from minimum to maximum and back every 2.87 days. Algol appears nearly overhead after darkness falls and dips low in the northwest by the time of its minimum.
Thursday, March 9
Venus appears brilliant tonight, shining at magnitude –4.46. That makes it six times brighter than the evening sky’s second-brightest object, Jupiter. Our solar system’s second planet shows up easily in the west within a half-hour after sunset and grows even more prominent as darkness settles over the landscape. The planet lies among the background stars of Pisces the Fish. At sunset, Venus will stand 23° above the horizon. When viewed through a telescope this evening, Venus appears 40" across and 27 percent illuminated. A week from now, its disk will span 53" and show a crescent only 8.7 percent illuminated.