The roll-off roof shed just grew without any particular long term planning from a 4 inch. concrete filled heavy walled pipe set in concrete in my backyard. In 1994 1.2 cu. metres of ready-mix concrete was used to make an 8' x 8' floor and the initial welded frame roll-off roof shed constructed. As Barraba has winter temperatures down to -8 deg. C in the winter the PC annex was added several years later. This image is of the original very light-weight roof which while very simple and easy to roll off wasn't very waterproof in driving rain and wind.
The original roof structure was replaced by a much heavier one piece construction with a split drum winch. This roof is MUCH heavier and requires a hand winch to reliably move it on and off. But it is totally waterproof and allows much better cooling of the observatory in summer. The roof is near white and it would be much better if the shed sides were white also but I am 'not allowed' to paint it white. The only disadvantage I have found in the last 18 months is the ease of access for mud-hornets which loved building their mud nests inside. By filling in a large water-pond and mulching the garden with sugar-cane mulch this problem has nearly been eliminated.
Homemade solid shaft split drum winch. This only undergoes lifting forces. Wind anti-clockwise to remove roof and vice versa.
The winch uses a length of soft terylene water-ski tow rope running over stainless yachting type pulleys to pull the roof open or closed. I originally looked at electric winches to do this but decided it was un-necessarily complicated for my requirements as well as having potential problems in power outages.
The pulley used as the fulcrum point to close the roof. This had to be a point inside the winch end of the shed.
A large strap type door hinge is used with a SS yacht type pulley welded to it.
One of the 4 ball bearing solid rubber tyre metal centre wheels used to carry the roof. These have proved to be inadequate for the weight involved and are splitting the rubber tyre on 2 of the wheels. They are quiet but will have to be replaced probably with fabricated steel wheels of the right diameter. Note the simple Anti-Lift brackets running under the rails beside each wheel. The steel frame of the quite light weight shed is welded and bolted to the concrete slab.
Room is at a premium with an 8' x 8' space for the scope.
The pier consists of a heavy walled galvanized steel column used to hold traffic light arrays at intersections. This is on 1" dia. jackscrews set in the 8ft square concrete base which is 6-8" thick on top of a clay soil.
Tak CN212 mounted on Anssen Alhena GEM
STL11KM with Canon 200mm lens and Robofocus & ST6B Guider for Ha and RGB imaging. This setup does not allow the STL to be rotated of course.
The new (Oct 07) Peristaltic Pump for camera cooling. Click on the above image for more detail.
Alloy bar to carry cables clear of AP1200 Control Box