Observing Calendars

May Observing Calendar   This month we'll focus on the Virgo Galaxy Cluster, but first, let's spend a moment on cosmology, the origin and evolution of the universe. Our universe is now pretty well established to be 13.5 to 13.7 billion years old. Our solar system is about 10 billion years old, and the earth is about 5 billion years old. For the initial 300,000 years after the "Big Bang", the phrase coined to signify the birth of the universe, matter existed in a super-dense soup of sub-atomic particles so hot and so dense that matter could not be formed. These particles then cooled and expanded sufficiently that the first atomic particles , namely hydrogen, were formed. Because of the randomness explained by quantum mechanics, the cooling was not entirely uniform. As a result, stellar matter tended to form in clumps. These clumps continued to coalesce as the universe expanded. Today we see the result as a series of ever smaller groupings of matter. First, super clusters of galaxies containing galactic clusters followed by galaxies themselves. Our Milky Way Galaxy belongs to a group of more than thirty galaxies called the Local Group. Within galaxies, we find globular clusters which are tightly bound groupings of stars. Open clusters, are smaller and less gravitationally bound groupings, followed by star systems of one or many stars such as binaries, triples, and so on. Within star systems, we find planetary systems such as our solar system. Today more than fifty stars have been found to have planets bound to them. We can continue this pattern down to the atom and its component parts, all originating from the same "spark of creation" started almost 14 billion years ago! Now lets relate this to the Virgo Galaxy Cluster, more properly referred to as the Coma-Virgo Supercluster. More than three thousand galaxies have been identified in this cluster, and over one hundred are within reach of a good 8-inch amateur telescope. Fourteen are on the Messier List. Find Denebola, the tail of Leo (See April Observing List). Scan toward the horizon and spot a star of about equal brightness to Denebola, this is Porrima, the center star in the constellation Virgo, The Virgin. Now continue toward the horizon and note the very bright star, Spica. Move back to Porrima. This is the base of a "Y" of three stars (including Porrima). Count two stars to the left and up. This is Vindemiatrix and appears slightly reddish or orangish. This is your starting point. Draw an imaginary line to Denebola and scan slowly toward Denebola. You should begin to see "faint fuzzies" beginning about a third of the way up. The bulk of them will be drifting left of that imaginary line. The concentration will continue to about half-way to Denebola. Depending upon your telescope size and field of view, you may see multiple galaxies in the same field of view. Scan right and left throughout this area and you will be treated to a view of a great galaxy cluster. They range from 40 to 50 million light-years away. Now return to Vindemiatrix. Notice the angle formed by the middle star in this leg of the "Y" and Vindemiatrix. Extend that line northeast and you will come to another reasonably bright star. This star and the star further northeast and higher in the zenith form the constellation Coma Berenises, Bernice's Hair. Return to the lower star. Move your eyepiece slowly north keeping it at about the same horizontal plane. About one degree north of this base star is the very attractive globular cluster M53. (Another less notable cluster is one degree southwest of M53; don't confuse them.) M53 is about 65,000 light-years distant and offers a total luminosity of 330,000 suns. Note the horizontal distance between Vindemiatrix and M53. Continue northeast on the same horizontal plane about twice that distance and you come to M3, one of the three brightest and most spectacular globular clusters in our sky. M3 is believed to be about 30,000 light-years away, and contain 45,000 stars within its 130 light-year diameter. Its total luminosity is about 260,000 suns.