Telescope Reviews: Building a portable observatory.building the walls

I’ve built a portable observatory using 1 inch PVC for the frame. The friction fit is sufficient to hold the frame together though I haven’t tried setting it up in a high wind. If the fit doesn’t hold in high wind I will add pins in the joints for ease of assembly and disassembly. I use a 45 degree elbow and a tee at the corners so the frame is a free standing octagon with an open top. (I also have plans for a dome top but haven’t built it, it can be added later at any time.) For the light shield I used tarps; I used the heaviest industrial tarps I could find to block as much light pollution from my Chicago area as possible. The tarps have grommets and I hang them from the frame using shower curtain hangers. To tie the tarps together along the sides I use tarp tie downs with toggle balls. I loop the tie down through the grommets and around the frame and they stay in place.

Here is a parts list with what I paid for each. The dimension “X” is the width of each of the 8 sides, “H” is the height. You can see the tarps are the most expensive component, and cheaper tarps are available though they are generally thinner and may not block as much light. The 10x12 foot tarp is just an optional cover for use at remote locations to cover the scope and observatory when not in use, it isn’t necessary. No component is over 40 inches long and the entire observatory takes up about 2-3 cubic feet of space when disassembled. I don’t have any pictures but I have attached a simple diagram in a power point slide if you’re interested.

Base requirements for 1 inch schedule 40 PVC pipe:
120 inch sections – 11 each ($2.29 x 11= $25.19)
Tee couplings – 16 each ($0.49 x 16 = $7.84)
45 degree elbow couplings – 16 each ($0.68 x 16 = $10.88)
Straight Coupling – 8 each ($0.29 X 8 = $2.32)
6x8 foot heavy duty tarpaulins – 4 each ($17.99 x 4 = $71.96)
Shower curtain hangers (12 pack) – 2 each ($0.96 x 2 = $1.92)
Toggle ball tie downs – 20 each ($7.49 x 2 = $14.98)
10x12 foot tarpauline cover (Optional) – 1 each ($39.99 x 1 = $39.99)
Total cost = $132.77 (+ $2.32 w/ couplings) (+ $39.99 w/ cover) + tax

1. Cut all 11 of the 120 inch sections into thirds (33 x 40 inch sections)
2. Cut 1 of the 40 inch sections into 16 x 2 inch sections (16 x 2 inch sections)
The 2 inch sections are used to couple the 45 degree elbows to the tees.
The 8 vertical supports are constructed of 2 40 inch sections each connected by a straight coupling.
A tee and 45 degree elbow are used at the top and bottom of each vertical support for the corners.
The remaining 16 40 inch sections form the perimeter of the top and bottom.

Tees will add 3 inches to height of H, total = 83 inches
Couplings will add 1 inch to height of H, total = 84 inches
45 degree elbow + tee will add 4 inches to width of X, total = 44 inches
Effective height = 7 feet
Effective perimeter = 29 feet 4 inches
Effective diameter = 8 feet 10 inches to 9 feet 7 inches. Average = 9 feet 4 inches.

Edited by MikeBu (10/01/08 11:54 AM)