Monday, March 13
Mars continues to put on a nice show these March evenings. It appears 20° high in the west once twilight fades to darkness and doesn’t set until after 10 p.m. local daylight time. The magnitude 1.4 Red Planet lies among the background stars of Aries the Ram. Unfortunately, Mars shows no detail on its 4"-diameter disk when viewed through a telescope.
Tuesday, March 14
By 10 p.m. local daylight time this evening, you can find Jupiter rising in the eastern sky in the company of a waning gibbous Moon. The two wheel across the sky in tandem tonight, reaching their peak altitudes in the south during the wee hours. The giant planet shines at magnitude –2.4 this week against the backdrop of central Virgo, some 5° north-northwest of that constellation’s brightest star, 1st-magnitude Spica. Even a small telescope reveals Jupiter’s 43"-diameter disk and four bright moons.
As midnight approaches, look to the east for the bright star Arcturus. At magnitude 0.0, it is the second-brightest star visible from mid-northern latitudes. If you scan about 20° to the left and a little below this luminary, you should see a conspicuous semicircle of stars — the constellation Corona Borealis the Northern Crown. It’s the most prominent group of stars having a shape reminiscent of a circle, and it makes a fitting target for Pi Day. (For you non-geeks, Pi Day is 3/14 because the first three digits of the mathematical constant pi are 3.14. Pi is the ratio of a circle’s circumference to its diameter, so today we celebrate all things circular.)
Wednesday, March 15
March evenings offer an excellent chance to see the zodiacal light. From the Northern Hemisphere, late winter and early spring are great times to observe this elusive glow after sunset. It appears slightly fainter than the Milky Way, so you’ll need a clear moonless sky and an observing site located far from the city. With the waning gibbous Moon now exiting the early evening sky, prime viewing conditions will extend from now through March 28. Look for the cone-shaped glow, which has a broad base and points nearly straight up from the western horizon, after the last vestiges of twilight have faded away.
Thursday, March 16
If you head outside after darkness falls tonight and look due west, you’ll see the stars of Taurus the Bull nearly halfway to the zenith. The tip of the V-shaped Hyades star cluster, which forms the Bull’s face, points straight toward the horizon. To the right of the Hyades lies the spectacular Pleiades star cluster (M45) and to the left are the glittering jewels that form Orion the Hunter’s shape.
Target Jupiter through a telescope tonight and you’ll think the planet has a “black eye.” The dark shadow of the solar system’s largest moon, Ganymede, transits the gas giant’s cloud tops starting at 2:36 a.m. EDT tomorrow morning (11:36 p.m. PDT this evening). The moon itself starts to transit the planet’s disk at 4:53 a.m. EDT, just 12 minutes before the shadow lifts back into space.