Tuesday, January 5
A favorite wintertime constellation is rising a few hours after dark: Canis Major the Big Dog. Famous for containing the Northern Hemisphere’s brightest star, Sirius, Canis Major holds other delectable sky treats as well.
One of the best is the open cluster M41, a dazzling sight through binoculars or a small telescope. (If you have good skies and you let the constellation rise higher, you may also spot it with the naked eye.) M41 is easy to locate — you’ll find it 4° south of Sirius, housed within the stars outlining Canis Major’s body, in the region often depicted as the dog’s neck. M41 spans some 25 light-years in space and is roughly 200 million years old — definitely young by stellar standards. It lies a little over 2,000 light-years away.
If you’re looking for something a little more challenging, try Thor’s Helmet — more formally known as NGC 2359. This emission nebula spans some 30 light-years and in its center is a hot Wolf-Rayet star nearing the end of its short life; when its time is up, it will explode in a brilliant supernova.
The nebula is located 8.8° east-northeast of Sirius. To bring out any detail, you’ll want to use an 8-inch or larger telescope; alternatively, a long-exposure photograph even through a slightly smaller instrument may start to reveal the nebula’s delicate detail.
Sunrise: 7:22 A.M.
Sunset: 4:49 P.M.
Moonrise: 12:00 A.M.
Moonset: 11:37 A.M.
Moon Phase: Waning gibbous (57%)
Wednesday, January 6
Last Quarter Moon occurs today at 4:37 A.M. EST. According to
Astronomy columnist Bob Berman, Last (or Third) Quarter Moon is “our strange, orphaned, unobserved Moon” because lunar observers rarely think to look for the Moon before dawn.
But now that you know better, consider rising early this morning to look at the Moon. In this phase, the crater Copernicus is on full display just south of Mare Imbrium. Astronomers know it is young because it’s remarkably well preserved and surrounded by a bright system of rays. The crater has several central mountains (a common feature) likely created when deep lunar material rebounded following the impact itself.
Other easy-to-find features visible during Last Quarter are the Apennine Mountains, which curve around the base of Mare Imbrium and appear to point right to Copernicus. And in the lunar south is the large crater Clavius, which contains a unique curl of small craterlets within its large, low walls.
Of course, you don’t
have to get up early to observe the Last Quarter Moon. It’s up all morning and sets around noon, so you can follow it even as the Sun rises. Just take care when using any optical aid to observe the Moon — even though it’s relatively far from the Sun, you don’t want to swing your gaze around and get an eyeful of concentrated sunlight.
Sunrise: 7:22 A.M.
Sunset: 4:50 P.M.
Moonrise: —
Moonset: 12:04 P.M.
Moon Phase: Waning crescent (46%)