By Vernon Whetstone
We have been looking at the large constellations and some of the other “big boys” of the astronomical world, how about if we shift to a few of the smallest. These three won’t be too difficult to find, they are all very near to each other.
Let’s start with the “where.” All three of these small constellations are quite near Aquila, the Eagle. Altair, the brightest star in Aquila is one of the stars of the Summer Triangle and we have all had practice finding it.
However, we will need to be in a dark-sky location for our star hunting.
Go outside about 8:30 p.m. MDT any night this week. Look about halfway up the northeastern sky to find Altair, it is the bottom-most star of the Summer Triangle. Deneb, the tail of Cygnus is off to the left, and Vega, the brightest star in Lyra, the Harp is the highest.
Now, having found Aquila, look slightly up and to the left between Aquila and Cygnus for a small group of five stars looking somewhat like an arrow with a shaft and feathers on the end.
That is indeed what it is, Sagitta (pronounced sa-GIT-ta) the Arrow.
Sagitta is the third smallest constellation in the northern sky and is related somewhat to Sagittarius, the Archer. Some folks think perhaps it is an arrow shot at the Eagle by the Archer. Good thing he missed.
Next, move down below Sagitta, below and left of Altair for our next small guy, Delphinus, the Dolphin (pronounced del-FINE-us). Easy to see, a small diamond shape with a tail, looking very much like a playful dolphin in our heavenly sea.
Now, moving further down for a small almost square shape of Equuleus (pronounced ek-KWOO-lee-us), the Little Horse. I don’t know if I should call Equuleus a small square, or a long rectangle.
Equuleus is the small horse, or perhaps even a colt. It is the smallest constellation in the northern skies. Crux, the Southern Cross is the smallest of all 88 of the recognized constellations.
It is very near the star Enif, the nose of the flying horse Pegasus. Perhaps it is the foal of Pegasus.
There are a few more small constellations in this area, but I think these three will be enough to keep you looking. Binoculars will help.
Now, one more thing. We have visited Brochii’s Cluster before, but it is always fun to come back to this unusual grouping of stars. Especially now.
The cluster is also known as the “Coat hanger Cluster” because that is exactly what it looks like.
Binoculars will be essential for finding this small group. Look about a third of the way along a line drawn from Altair to Vega, just up and slightly right of Sagitta.
Five stars form a bar and a few more stars form a coat hanger hook below the bar. Remember, binoculars ARE essential.
Now then, if you are really on the ball and can find Brocchi’s Cluster in your binoculars, in the same field of view you will be able to see another celestial wonder, eighth magnitude comet Garradd (C/2009p1). If you miss it tonight (Wednesday), you will have seven more nights to find it each evening close to the Coat hanger. Happy hunting.
SKY WATCH: First quarter Moon, Sunday, Sept. 4. Saturn is about to leave the evening sky and Jupiter is joining it after about 10:30 p.m MDT. If you are an early riser this week is a good opportunity to catch fleet-footed Mercury as it makes a quick appearance in the morning sky. Look in the east beginning about 5:45 a.m. MDT for the small, pink dot that is Mercury. Watch it all this week as it rises higher. There will be a nice meeting Mercury and Regulus on Sept. 9.