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Gerry Descoteaux
The Lawnchair Astronomer

Delightfully December

Canis Major and Minor

The big and little dogs, (Canis Major and Minor) as well as the not necessarily related, though often mistakenly considered a canine related group of stars known as Puppis are home to some excellent Lawnchair Chest Trophies.  Here is where the field of view is thick in the marvelous realm of the Milky way.

 The big dog heels along the Hunter's (Orion) right leg while the little dog can be found east of his outstretched sword, below the Twins of Gemini.  Canis Minor is, as expected, a small constellation made up of just a few stars.  One, quite bright however, is known as Procyon.  There’s not much to say about Canis Minor, other than that its Alpha, Procyon, is a wonderfully bright star in small telescopes.  It’s not as bright as its larger sibling however.

Since antiquity Canis Minor has been known to the ancients, translated from "Before the Dog", as it rises just prior to the triumphant return of Sirius.  Very difficult to split telescopically, Procyon is a double star.  This is because of how bright the main star is.  However, its partner is a massive white dwarf star.  Procyon is the 8th brightest star in the sky and also of the group considered the closest to Earth.  There aren’t really any DSOs for backyard telescopes in the area of Canis Minor.


Not necessarily the "piece de resistance", Canis Major, below the Unicorn is, of course, home to Sirius, the very brightest star in the entire sky.  As always, I am enraptured by this most incredible view of a star that one could experience.  The Hershels, (brother and sister) seventeen hundreds era astronomers, described it in their notes:  "It was like dawn breaking in the morning as the mighty Sirius entered into the eyepiece, its incredible brightness almost intolerable to the eye." And I, too, am amazed every time I've trained a telescope onto Orion's canine companion.

If you've ever wondered what a really bright star looks like in a pair of binoculars or a quality telescope, this is the one to view.  Actually a very close double star – like Procyon we can't see the secondary because it's so close   Sirius when emerged from the glare of the sun each spring, was used by the ancient Egyptian astronomers to predict the annual flooding of the Nile.  Don't miss a chance to add this southern stellar beacon to your personal Lawnchair Trophy Chest.  Even in binoculars or a small telescope, this sight awes even the most seasoned astronomers.

There's also more than meets the eye in this neighborhood of celestial sparkles.  With the aid of a small or medium-sized telescope, there’s a wonderful open cluster to view just below the belly of the Big Dog.  M 41 is a loose cluster of bright stars that only gets better as you move from a wide angle view to a close up lens.  M 50, just ahead of the doggy's snout, is another wonderful cluster with both blue and red super giants headlining the group.

Following closely behind and below the Canis Major constellation is a little seemingly sparse group of stars, one of which is cataloged as "one of the very largest and most spectacular in the sky".  It is also home to the wondrous star fields of the Milky way.  The constellation of Puppis is home to Zeta Puppis, a supergiant star that is perhaps one of the very most luminous stars in our galaxy.  If it were as near to us as other bright stars, like Sirius or Vega for instance, it would shine brighter than the planet Venus and would even be visible in the daytime.  Look for Zeta Puppis near to the horizon, along the line of sight from Sirius passing through its hind quarter stars, down to the horizon.

When the constellation of Puppis climbs up from the horizon, arching up over the back of the big dog, here is where you can find some excellent binocular and small telescope targets.  The star clusters M 93, M 46 and M47 are all wonderfully diverse, each containing a hodgepodge of bright and dim stars.  In small scopes getting them into the same field of view may not be possible depending on the type of lens you use.  M 46 is the larger but more distant and dimmer of the two clusters.  It contains hundreds of dim white stars.  Also included in this area is a small planetary nebula, NGC 2438, which has only recently been confirmed as not having a relationship with the cluster itself.  Both are receding from us at incredible speeds, but from varied distances and directions.  M 47 is the closer and brighter cluster, and though it contains substantially fewer stars, is still a visual treat. As I mentioned earlier, capturing the two in the same field of view makes for an exceptionally striking picture.
 This whole area of the sky is worth scanning.  In both small and large backyard scopes, these rich fields of stars are simply breathtaking.  As I mentioned earlier, though Puppis sounds like a dog like group of stars, it was actually once part of a group of water based constellations.  Mythologically speaking, it was originally part of the ship belonging to Jason and the Argonauts, (Arvo Novis) a once larger constellation which was divided into its now constituent sections.  Puppis represents what in modern times is known as the poop deck (Insert tongue in cheek comment here).

Also near Zeta Puppis, approximately 2.5 degrees to the northwest, resides a very fine open cluster. NGC 2477 is, because of its position very near the southern horizon, not a very well-known or often viewed cluster, especially for northern observers. Under ideal seeing conditions, it can be spotted in medium sized scopes, though, the larger instrument has a much better chance of resolving it.

M 93 can be found just above the star known as Xi Pup. It is a smaller fuzzy than the previous Messiers described above.  You may glimpse it in a small instrument, though a larger device will be required to resolve it into more than just a group of blurry stars.  Another easily located cluster is NGC 2539.  Found near the top star of the constellation, 19 Puppis, this is a classic open cluster.  Hardly as compact as M 46 and M-93, but high enough off the horizon, that this is easily one of the Messiers that you'll be glad you were able to add to your Lawnchair Trophy Chest!


Below the little and big dogs, Monoceros, Greek for Unicorn, is one of the dimmest constellations and quite hard to make out with eyes alone.  Of note, however, Monoceros was found to be home to a few recently discovered exoplanets.  Each are what have been described as super earth sized globes.  Unfortunately, their existence can only be detected by the wobble they produce in their parent stars.  Neither are available to see in backyard instruments.
Monoceros is the W-shaped constellation sitting in between Orion (to the east or left) and just above Canis Major, between it and its prodigy, Canis Minor.  Within the boundaries of Monoceros reside several exotic celestial jewels.  Perhaps the most famous is the Rosetta Nebula which enshrouds a star cluster cataloged as NGC 2244. The Nebula itself, NGC 2237 resembles a rose, thus its name. This particular object will look nothing like its slick color photographs in small telescopes or binoculars.  The cluster, however, is naked eye visible.  But, to see the nebulosity as more than a thin wispy veil about the cluster will take at least an eight to ten inch instrument and a very dark and calm sky.  The area is also intertwined with both bright and dark nebulous materials.

The centered rectangular shaped cluster contains the yellow giant star, 12 Monocerotis and has its own mystery as well. A debate still persists as to its actual distance and membership to the cluster as well as a determination as to its exact spectral type. One possible theory concerning the nebula and star cluster is that this object, because of its many globular sections may perhaps be a proto planetary system, or on the other end of the spectrum, just the remnants of a giant cloud of gas and dust that resulted with the birth of the star cluster we see today. It may still be possible that this material could supply fuel for more stars or for the aforementioned new planetary system.

Another point of interest centered in the area just under the middle arches of the Monoceros W is M 50, a fine open cluster of about two hundred stars compressed into a rather small area.  Naked-eye visible under ideal seeing conditions, this is a treat for binoculars and small telescopes. Imbedded in the conglomeration of mostly white and blue stars, is a ruddy or reddish star, which makes for an exquisite contrast. This cluster has often times been described as heart shaped.
There are still other nebulosities and dim galactic clusters throughout Monoceros. A wide angle lens and a dark sky should make it possible to glimpse some of the brighter of these. Scan the area around the W after your eyes are truly dark adapted.

Clear Skies!

The Lawnchair Astronomer
Gerry Descoteaux is the author of “The Lawnchair Astronomer,” a Dell Trades paperback. He has been writing about astronomy for more than 25 years. He also played an integral role in the development of America Online’s pioneering distance education program known as AOL’s Online Campus and served as Professor of Astronomy there for 10 years. He can be reached at

Notes From the Lawnchair

The Lawnchair Astronomer
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