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March 15: Uranus meets 13 Tau
High in the south this evening is Canis Minor the Little Dog, shining above the bright star Sirius, which lies closer to the horizon. True to its name, the Little Dog is a little constellation, beating out fewer than 20 other constellations in size. However, it makes up in brightness what it lacks in stature: Canis Minor’s alpha star, Procyon, is the eighth-brightest star in the sky.
Shining at magnitude 0.34, Procyon is just 11.4 light-years from Earth. It shines as brightly as seven Suns and is roughly one and a half times the mass of our home star. And like its counterpart Sirius in Canis Major, Procyon has a white dwarf companion. Glowing a far fainter 11th magnitude, this tiny stellar corpse lies less than 5” of Procyon and is a true challenge to view in amateur scopes.
The Little Dog’s second-brightest star is Beta (β) Canis Minoris, also called Gomeisa. It shines at 3rd magnitude just over 4° northwest of Procyon, to the brighter star’s upper right in the sky as you look south this evening.
Sunrise: 7:10 A.M.
Sunset: 7:08 P.M.
Moonrise: 6:01 A.M.
Moonset: 4:44 P.M.
Moon Phase: Waning crescent (5%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40° N 90° W. The Moon’s illumination is given at 10 P.M. local time from the same location.
The Moon passes 2° south of Mercury at 10 A.M. EDT on March 17, then passes 1.5° north of Mars at 6 P.M. EDT. Both planets are in the early-morning sky, and the trio is visible for only a short time before sunrise. Just 20 minutes before sunrise, Mars is only 1° high and magnitude 1.1. Mercury is higher — 5° above the horizon — but even fainter, at magnitude 1.7. And the waning Moon, which might normally serve as a beacon and steppingstone, is just 3 percent lit, one day from New.
A much easier observation early Tuesday morning is the lovely open cluster M29 in Cygnus the Swan. Around 5 A.M. local daylight time, M29 is some 35° high in the east. It’s easy to find, too, located just under 2° south of 2nd-magnitude Sadir (Gamma [γ] Cygni), which serves as the center point in the cross-shaped constellation Cygnus.
Spanning about 7’, M29 shines at 7th magnitude and is a great target for binoculars or any small scope. In fact, lower powers are better when looking with a telescope, allowing you to view the entirety of this young open cluster at once.
This cluster was named the Cooling Tower by amateur astronomer Jeff Bondono, who thought its brightest stars sketched out the curved outline of a nuclear power plant’s iconic cooling tower.
