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But I knew there would be another visitor as well! I recently saw a finder map for comet 71P/Clark. It is not particularly bright, but visible as a small greenish smudge not far from the left edge. The right image shows it a little better, complete with a little tail trailing off to the upper right! Comets that display any color usually show some green - caused by the sunlight breaking up carbon molecules that will glow green in the vacuum of space.
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My main goal for the night was a "bright" comet - C/2015 V2 Johnson! When it comes to comets, most anything visible in a small telescope or binoculars is considered bright, and unfortunately, this one will not quite be visible to the naked eye. Some of you know that Melinda's maiden name was Johnson, and as far as I know, the discoverer of Comet Johnson is not a relative! He is Jess Johnson, and works for the Catalina Sky Survey right here in Tucson. This comet was discovered as a faint smudge in November of 2015, and is just now at its closest point to the sun and the earth. We'll be able to show it as part of the Grand Canyon Star Party this June, after which, it will slowly be leaving the solar system - its hyperbolic orbit means it will not return to our part of the solar system again. With the 500mm lens, I got 10 frames of 2 minutes each and used the "Nebulosity" program to stack the images on the slowly-moving comet image. The result is at left. The bright star at right is Epsilon Bootes, and the comet is slowly moving almost due south.
What is interesting about the comet is that when zooming in, a sun-ward pointing spike appears! This usually indicates that the earth is passing through the orbital plane of the comet. At right is a cropped, stretched version perhaps showing it more clearly. These sunward spikes are illusions and are actually well beyond the comet. The solar wind pushes released gas and dust away from the sun to make the tail, and as we pass the plane of its motion, long-ago releases material can appear to point towards the sun.
That was the highlight of my Saturday at CAC. I tried some similar low Milky Way objects, but ran into some of the light dome off of Douglas 20 miles south of the observing site. Best to stay higher in the sky! I'm spoiled by the black high-elevation skies of Kitt Peak... Oh, and I did get a glimpse thru the 40"! While my camera was shooting comet Johnson, I ambled up and was just in time to view the huge globular cluster Omega Centauri. With it so low, no stepstool was needed, so extremely comfortable to observe. The cluster looked for all the world like a swarm of fireflies as the long path thru the atmosphere made the stars dance wildly! It was a sight not easily forgotten!