It’s time to discover Canis Main. Open cluster M41 is a superb goal for naked-eye observers, the Tau Canis Majoris Cluster presents small-telescope homeowners good views, and large-telescope homeowners can search out Thor’s Helmet.
Astronomy targets for Feb. 14–21
Bare eye: Open cluster M41
Small telescope: The Tau Canis Majoris Cluster (NGC 2362)
Giant telescope: Thor’s Helmet (NGC 2359)
Observe the sensible information
This week’s naked-eye object is open cluster M41, which lies in Canis Major the Great Dog. It’s simple to seek out M41 on any clear winter evening. First, discover Sirius (Alpha [α] Canis Majoris), the evening sky’s brightest star. Then look 4° due south.
As a result of it glows at magnitude 4.5, most observers ought to be capable to pick M41 simply with their bare eyes underneath a darkish sky. This cluster lies 2,000 light-years away and measures about 20 light-years throughout.
Now simply because you possibly can see M41 with out optical support doesn’t imply you shouldn’t level your binoculars or telescope at it. Even a low-power view reveals dozens of stars with a Seventh-magnitude orange gem on the cluster’s heart.
Prepare your telescope on Tau
This week’s small telescope goal is the Tau (τ) Canis Majoris Cluster, often known as NGC 2362. From M41, transfer 8.6° east-southeast. With unaided eyes, you’ll discover a glow across the 4th-magnitude star Tau CMa. If you level your telescope at this object, nonetheless, you’ll have an entire new perspective.
Tau CMa varieties the centerpiece of this terrific star cluster. A 4-inch scope will present stars in three tiers of brightness. First, there’s sensible Tau. Then, 3 magnitudes fainter, a half-dozen different stars catch your gaze. Lastly, you’ll spot the faintest stars, which glow at tenth magnitude. Look carefully for the tight group of those stars spanning 6′ that surrounds Tau. Don’t let the brilliance of the principal luminary deter you.
For Asgard!
This week’s deep-sky object is my alternative for “best-named” celestial goal — Thor’s Helmet. Some historic illustrations (and all the 600-issue run of the Marvel Comics’ superhero epic) image the Norse thunder god Thor carrying a winged helmet. Nicely, via a big scope, this nebula, often known as NGC 2359, seems to be like a helmet with wings.
Thor’s Helmet completes this week’s trio of objects that lie in Canis Main. It sits 8.8° east-northeast of Sirius. This celestial deal with is a cosmic bubble sculpted by radiation from a sort of luminous, huge star known as a Wolf-Rayet star.
French astronomers Charles Joseph Étienne Wolf and Georges Antoine Pons Rayet found this stellar sort spectroscopically in 1867. These short-lived supergiant stars are uncommon; astronomers have found fewer than 250 of them inside the Milky Way.
To reinforce NGC 2359’s visible look, use a nebula filter similar to an Oxygen-III (OIII). By a 12-inch telescope, you’ll see the round central space and the helmet’s two “wings.” The brightest half measures 1′ large and extends to the south roughly 4′.
