9/14/2013
by Matt White
A partly cloudy Saturday morphed into a beautiful clear night for star gazing. When I arrived at Seagrave, Steve Siok had already started prepping the Clark for the evening session. In addition to our public night, we were expecting a group of twenty people from the Greenville Public Library. A few minutes later, we were joined by Dave Huestis and Alex Bergman.
Steve, Alex, and I, trained the scope over to the slightly past first quarter moon and focused on the terminator near the lunar south pole. Using a 40mm eyepiece with a filter gave us a magnification of 66x, providing a spectacular view of the lunar surface. With four other scopes in operation, we had a steady stream of visitors throughout the evening. Steve opted to keep the Alvan Clark on the moon for most of the session.
Towards the end of the evening, after everyone had seen the moon, we moved over to Albireo or Beta Cygni, the fifth brightest star in the constellation of Cygnus. This binary pair is about 380 light years distant and is one of the most beautiful objects in the heavens. At 35 arc-seconds, the pair is easily split even in a modest telescope and the object has the best color contrast (yellow/blue) of any double star. For this object, we selected a 25mm eyepiece, giving a magnification factor of 108. Albireo A also has a companion, but the separation is only .4 arc-seconds; too close to be resolved visually in a small scope.
Dave wanted to show our remaining three guests M57, the Ring Nebula, so we slewed up to Lyra. M57, a planetary nebula, 2300 light years distant, the Ring lies between Gamma Lyrae (Sulafat) and the eclipsing double Beta Lyrae (Sheliak). At magnitude 8.8, the ring is only visible through a telescope and can be somewhat elusive despite being located between two brighter stars. I was unable to see it in the finder so I chose a spot between the two stars. When I looked through the main scope, the ring was in the very bottom of the field. M57 contains a central white dwarf is difficult to spot having a magnitude 14.
We had about thirty five guests; including twenty from the Greenville Library join us over the course of the evening.
