Log, Feb 4, 2005

3 people. Ernie Evans, Joe Harley and Les Coleman showed up for what proved to be a rather odd night at FDO. When Les got there, the southern horizon directly over the ocean was brilliantly illuminated. It looked like the lights of a small stadium or a fair but it was beyond the barrier island. It was two boats or barges working in Foster Cove doing who knows what. If they stay then our dark skies will be a travesty. I hope they are something like dredges that will move on.

We tried to view the Pup (Sirius B - the white dwarf). We got hints that we could see it and this lead us to trying to improve the image by doing a long needed collimation. Everything went all right until a collimation knob slipped out of the mirror mount and just would not go back in.

On Sunday, Joe came down to fix the collimation problem. In an exaggerated view, one of the three knobs (setting screws) could not reach the back of the mirror which was tilted too much when the other two knobs were too tight. We cannot loosen the other two screws with one out of place because then entire assembly might swivel out of position. The fix is simple, but requires an identically threaded set screw which is an inch longer than the originals. Simply slide it in, tighten slightly, gently loosen the others, tweak a bit and finally level the secondary mirror. Looks easy to do when you are wide awake and your fingers aren't too cold.

The Charlestown Police noticed activity at the Observatory and gave Les Coleman a call who explained that all was well. The "perpetrator" was none other than our very own Joe Hartley making delicate adjustments to the mirror in the light of day when the temperature was well above freezing. In any case, all's well that ends well.

-Les Coleman

Leslie Coleman
Leslie Coleman
Entry Date:
Feb 4, 2005
Published Under:
Leslie Coleman's Log
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