Friday, March 14, 2014

A (Telescope) Pier Is Born And The Home "Observatory" Is Almost Finished

A couple of months ago, I decided that if I was going to do astrophotography justice, I needed to have a semi-permanent home for my telescopes, computer and all the paraphernalia that I use when shooting the heavens above. I set out to build something in my back yard to use and no sooner had I started building my home setup, I stumbled across a high school classmate who owns property at the Chiefland Astronomy Village. My friend graciously gave me use of a 10-foot dome observatory he was going to tear down after he built a larger roll-off roof observatory and I have now set up the dome in Chiefland as my primary astrophotography venue.

Even though I will be doing the bulk of my astrophotography in the dome, I still wanted a convenient backyard site in which to play around. Chiefland is a two-hour drive from home and as fortunate as I am to have such a primo site at my disposal, the distance between Tallahassee and Chiefland necessarily limits the opportunities to use my telescopes. I still wanted to have something right outside my back door to use on clear nights after dinner, so I pressed on with the home version of an observatory to use use for visual observing and some photography.

The home "observatory" began with a some-assembly-required storage shed from Home Depot. After building an elevated framed wood floor I assembled the shed. Inside, I set up a table with computer gear to have comfortable place to control a telescope, run planetarium software, and keep my gear dry from the night dew. I built a privacy fence around the shed to block out some of the stray light from our house and the neighbor's homes (above).

After everything was pretty much finished up, I finally had a chance to set up a telescope and spend an evening looking at different objects in the sky. When I tried to observe Jupiter with high magnification eyepieces, the "shake" caused by the tripod was frustrating. I was now spoiled by having a rock solid pier on which my imaging telescope is mounted in Chiefland so I decided to build a pier for my 8" and 6" Schmidt Cassegrain telescopes (the ones I use for observing).

The first step was to find a pier adapter for these telescopes. None were available which cased me to start the project by fabricating one. I covered the fabrication process in a prior post. With that step out of the way, it was time to build the pier.

One pier option was to use an 8" X 8" post, dig a hole and set it in concrete. Another option was to use 8" square cinder blocks, stack them in the shape of a column in a concrete filled hole, and fill the inside with rebar and concrete. In the end, I decided to use an 8" Sonotube form filled with rebar rods and concrete. I dug a 16" square hole 24 inches deep, filled it with concrete, and inserted three 4-foot rebar rods vertically into the concrete as it was setting. I placed the sonotube on top of the square foundation (above, left) and dug a 30-inch square by 6-inch deep perimeter around the pier foundation to give the pier a larger footprint for stability. A few more bags of concrete mixed and poured, badda boom badda bing the pier was beginning to take shape (above, right). In order to attach the pier adapter, I inserted four "L" shaped, 8-inch long, 1/2" bolts into the concrete in the sonotube with the threaded portions protruding above the top of the concrete (left).

After the concrete was completely set, I put the finishing touches on the pier, I built a 4-foot square deck around it making sure that the deck floor did not contact the concrete pier by cutting a square notch in the deck planks. The whole purpose of the pier is to minimize vibration transmitted to the telescope and by isolating the pier from the deck, I can walk on the deck without transmitting any vibration.

The final step in this project will be to finish the pier adapter by drilling holes in the bottom plate to attach the plate to the pier. The pier adapter will be bolted to the pier and leveled/secured with nuts and washers on both the underside and on top of the bottom plate. I'll cover the final steps in a post that will follow. If I can get some clear skies, I hope to test everything out with Venus, shining like a beacon to the East in the pre-dawn sky. 

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