Canis Minor, the Little Dog, is indeed a small galaxy with few observing highlights beyond its two bright stars.
The Mythology of Canis Minor
Canis Minor is the small counterpart to Canis Major, the Big Dog. Canis Minor is called the Little Dog and sometimes the Lesser Dog. Canis Major and Canis Minor are the faithful dogs of Orion, the Hunter. They are positioned to the left or Orion when viewing from the Northern Hemisphere. They rise after Orion in the winter. Canis Minor has occasionally been referred to as a Water Dog, because part of the constellation lies on the Milky Way, the great river of stars in the sky.
Finding the Constellation of the Little Dog
Canis Minor is easiest to see in the winter time. It rises after sunset trailing Orion. It lies a short distance away from the bright shoulder stars in Orion. Another way to find it is by looking beside the twins of Gemini. Only two stars will make the constellation stick out , and both of them are relatively bright.
Observing Targets in Canis Minor
This mostly obscure constellation is home to one of the ten brightest stars in the sky. Procyon, or Alpha Canis Minoris, is the eighth brightest star at magnitude 0.40. The temperature of Procyon at 7000 degrees is similar to that of the sun. Unlike the sun, it has a white dwarf companion, which is best seen in professional telescopes. The reason Procyon appears so bright to us on Earth is because of its proximity: It lies a mere 11.4 light-years away.
The other bright star in Canis Minor is Gomeisa, or Beta Canis Minoris. Gomeisa shines at a magnitude 2.89, making it clear which of the two stars in Canis Minor is which. Gomeisa lies a much more distant 170 light-years away.
Deep-Sky Wonders in Canis Minor
There are a number of galaxies and nebulae in Canis Minor but the majority are too faint for the casual amateur astronomer. The brightest of these is only magnitude 13, the round galaxy NGC 2485. Because the Milky Way lies in the southwest portion of the constellation, the faint galaxies that you will find all lie in the northeast portion of Canis Minor's boundaries. You can think of the line drawn between Procyon and Gomeisa as the edge of the Milky Way.
Size of Constellations
While Canis Minor is not the smallest in order of size, it is one of the smaller ones. Out of the 88 constellations, Canis Minor ranks 71st. Most of the smallest constellations lie in the Southern Hemisphere, with Crux, the smallest of all 88, lying right on the South Celestial Pole.
