Dome trouble

Well, we had trouble, my friend! During our April 4, 2009 public night, the shutter began acting up. It was difficult to open for the night and was nearly impossible to close (see previous post)! College carpenters built up a scaffold inside the dome early in May and determined that the rollers that carry the shutter had derailed -- nominally the rollers move along an iron bar at the top of the opening easing operation. The craftsmen lifted the shutter back on to its tracks and lubricated the wheels. With the scaffold in place the telescope could not be moved so all use of the Observatory was suspended during the balance of April and through May. While the scaffolding was still in place, over the late-May Memorial Day weekend, I replaced the pull ropes that are used to manually open and close the shutter. I have no idea how old the cotton rope was; I replaced it with a tough poly braded rope. The shutter works better than it has in years though close examination of the condition of its wooden components left us with worries.

May offered a number of clear nights which was a big change from an otherwise very cloudy spring season. Unfortunately needing to be fresh for work and a nasty late-May head cold kept me from taking advantage of the clear night skies. Hopefully this will be a good year for me and I have hopes of using both the Observatory and my private telescope(s) more frequently than in recent years.

Photo: Crammed inside the Observatory dome is a large scaffold used by workers to repair the troublesome dome shutter. The hundred-year-old sliding wooden cover had become derailed. Taking advantage of the presence of the sturdy apparatus, I replaced operating ropes and inspected the upper reaches of the dome and shutter ... it wasn't pretty!

Tough night at the Observatory

Saturday night, April 4, was to be the first scheduled Public Night at the Observatory of the year not canceled by weather conditions. As forecast, the skies cleared and promised to cooperate for the night's event giving us fair seeing and temperatures in the mid-30s. Because of previous cancellations the Open Night was to serve as our official Saturn Observation Campaign event for the spring and we registered as a local site for the global "100 Hours of Astronomy" which is a part of the International Year of Astronomy observance.

Despite clear skies our events nearly did not happen. Pulling the ropes to open the observatory's dome shutter I head a loud squawk echo through the chamber -- the shutter had jammed for some reason and would not open fully and would not close. Repeated efforts finally resulted in the shutter opening all the way and we were free to see the sky.

The night saw 26 visitors between 9:00 and 11:00 and they were treated to superb views of the Earth's Moon. As usual the old nine-inch scope excelled at lunar landscapes but the Moon was very high in the sky --not far from the zenith-- and the telescope was not tracking well. We settled for moderate magnification (133X) and enjoyed nearly three-dimensional viewing of Mare Imbrium's crater-marked lava expanses. Wrinkled crater walls, mountain ranges, and long, low, lines of hills looking like frozen ripples in hardened plaster were seen vividly. Views of Saturn were also quite good: the rings tipped towards us at only about three degrees (minimum tilt was reached in January but we missed that). Moments of very good seeing revealed a slight shadow across the planetary disk cast by the rings and a hint of gap between the planet's limb and the inner rings. A special treat was the sight of four of Saturn's moons and, over the course of the evening, noting their changing positions relative to each other and to their planet. Galileo, 400 years ago, never saw the Moon or Saturn a fraction so well as we did. He was, however, very meticulous and a skilled observer of what he could see. The Moon, while beautiful to look at, also lit our less-than-perfectly transparent skies causing quite a bit of glow so we confined ourselves to viewing only it and Saturn. The last visitors departed at about 11:10 PM.

All was routine as I began closing up until I attempted to close the dome. Squawk, boom! The shutter stalled and jammed again on its tracks. This time, however, it was stuck. After many attempts with the ropes I climbed into the opening. I found one of the lower wheels on the shutter had derailed so I lifted the shutter back on to the track. Not enough! The main problem was with the track at the top of the dome! There's no way to reach that point without scaffolds or ladders. It was going on midnight and I didn't know what to do but to keep trying. If anyone was watching from outside it must have been quite a sight... the silhouette of a man in the aperture, bright lights on inside an observatory dome, pushing and pulling and shaking the shutter, until finally it settled into its closed position. Tired, sore, and worried, I shut off the lights, locked up, and headed home at about 12:30 EDT. What a night!