High overhead, in July, you’ll find the constellation Hercules. The four stars making up the top of Hercules is known as the Keystone, and if you point a telescope or binoculars to the west side of the Keystone, you’ll find one of my favorite objects: M13, a wonderful globular cluster. West of Hercules, you’ll see Corona Borealis and Bootes. Bootes is a kite-shaped group of stars and easy to pick out because of brilliant Arcturus. You can find Arcturus using the handy sky key that tells us to use the Big Dipper’s handle to “Arc to Arcturus then speed on to Spica,” which leads us directly to those two bright stars.
East of Hercules is Lyra, and then you’ll find Cygnus. The Summer Triangle is very apparent in the eastern sky. The Summer Triangle is made up of the three brightest stars in three different constellations. The most northern of the three stars is Deneb (in Cygnus), the most southern star is Altair (in Aquila) and the star making up the third star of the triangle is Vega (in Lyra).
Looking south you’ll see the “Teapot” of Sagittarius and a fishhook, which is the constellation of Scorpius above the southern horizon. They are both in the thick of the Milky Way, which you can follow upward in the sky going by Aquila, Cygnus and stretching through Cassiopeia in the northeast.
There are nine objects this month shining at first magnitude or brighter, and in order of brightness they are: Jupiter, Arcturus, Vega, Saturn, Altair, Antares, Spica, Deneb and Regulus. If you are away from city lights, try to find these naked-eye objects. Sweep down from under the handle of the big dipper looking for a dark area with a big glint of light on the sky – that is the galactic star cluster known as the Coma Cluster that contains more than 40 stars and covers over 4 degrees of the sky. Now look between the spout of the Teapot and the tail of Scorpius for the Lagoon Nebula; a cloud of gas and dust where stars are forming. Explore the summer Milky Way with binoculars, and you’ll find all sorts of amazing things!
Something fun to find on any clear night in July and August is the biggest summer constellation, which we call Scorpius (the scorpion). It is one of the few constellations that actually resembles its name and stands out above the Southern horizon. There is even a red star where the heart of the Scorpion should be and it is named Antares, a gigantic star 700 times wider than our Sun. You can also see how the tail curves up then back on itself just like a real scorpion with two stars marking its poisonous stinger. Their Arabic names from left to right are Shaula and Lesath, which mean “the sting.” In folk legend, they are not only “the sting” but are also the two eyes of an ancient celestial cat, which stare out at us every single summer leading to them commonly being referred to as the “Cat’s Eyes.” They definitely remind you of seeing the reflection of cat’s eyes in the dark.
Although these stars don’t appear to be all that exceptional to the naked eye, if we look deeper into these cat’s eyes and compare each star to our Sun, we find they are pretty impressive stars. While our Sun is about a million miles wide, Shaula is almost twice as wide. It is also a much hotter star than our Sun and is about 1,200 times more luminous. It looks dimmer to us because it is 360 light years away, which means that we see Shaula not as it exists now but as it existed when its light left it 360 years ago in the late 1600s. Shaula is the 24th brightest star in our sky. Lesath, the dimmer of the two, is even more incredible and appears dimmer only because it is farther away than Shaula, at 576 light years away, which means that we see it not as it exists now but as it existed in the 1400s. Lesath burns even hotter than Shaula and is 15,000 times brighter than our Sun. Lesath makes both Shaula and our Sun seem small by comparison because it is two and a half times the diameter of Shaula and seven times as wide as our Sun. Hopefully you’ll find these “Cat’s Eyes” some summer night and contemplate how remarkable those stars are in our night sky. If you have binoculars, you can see two nice open star clusters near the Cat’s Eyes. Draw a line from Lesath through Shaula and continue sweeping left and you’ll find a nice glowing cluster of stars we call Messier 7. After enjoying that cluster, sweep your binoculars upward and slightly right and you’ll find another lovely group of stars that kind of resembles a stick figure of a butterfly. This cluster is Messier 6. Happy stargazing.