Observing Calendars

August Observing Calendar   August brings us to witness the full breadth of the Milky Way as it spans Cassiopeia from the north, Cygnus almost overhead, to Sagittarius in the south. We are among the few still privileged with a sufficiently dark sky to witness it. (No, Johnny, it is not a cloud!) Let’s get oriented for a moment. The Milky Way Galaxy is a spiral galaxy estimated to be about 100,000 light-years across. Our sun is a middle-aged, average-sized, average temperature star in one of the outlying arms of our galaxy. When we look at the Milky Way, we are looking along the axis of the galaxy’s plane (which is why we see such a concentration of stars). Roughly speaking, Cassiopeia is looking away from the center of the galaxy, and Sagittarius is looking toward the center of the galaxy, which is about 30,000 light-years distant. If we look carefully overhead, we may see that the star field is actually split into two parallel bands running along the north-south axis. This dark band is the result of stellar dust particles between us and other stars in the galaxy obscuring their light from us. This feature is called the Great Rift. The Great Square of Pegasus is just becoming visible at dusk, reminding us that soon we will be able to see our sister galaxy, the Andromeda Galaxy, rising in the northeast. Looking from our zenith (overhead) to the north and east, we see Vega, one of the three brightest stars of the summer sky which form the Summer Triangle. Vega anchors the constellation Lyra which is the parallelogram just below it. M57, (click here for image- return by using Back button on Browser) the famous Ring Nebula, is located between the two stars on the right side of the parallelogram. It can be seen with a 3-inch telescope, but really begins to show its stuff in an 8-inch or larger scope. From Vega scan about 30 degrees east (toward the horizon) and you see Deneb in Cygnus. Cygnus, the Swan (sometimes referred to as the Northern Cross), holds two special objects the Veil Nebula and the great North America Nebula. The Veil is a complex series of wispy, veil-like streams of gases glowing from nearby stars. It can be difficult to see but is worth the effort. The North America Nebula is located about three degrees east of Deneb and its shape resembles the North American continent. Another interesting object in the Cygnus complex is the Cocoon Nebula. The final star forming the Summer Triangle is Altair in Aquila, or the Eagle Constellation. Finding these three stars and their associated constellations serve as sign posts for star-hopping the summer sky. Now is a very good time to view Sagittarius to the southeast. See September notes on this facinating constellation and it's many beautiful objects. August 26 is the magic date for viewing Mars. It will be the closest to earth in over 50,000 years. Its the brightest object in the southeast.