[pbrowne (Peter)]

Hi

I'm trying to work out the height that the wall of my small observatory should be for a 200cm x 200cm shed. This will house a Mach1GTO with a WO FLT-132 on a concrete pier 20.3 cm in diameter (8") and 122cm high (48 inches as recommended to me by George Whitney at Astro-Physics given the equipment above and my height of 5' 11").

At this stage I'm looking at existing zinc-alum shed modified by the manufacturer.

http://www.customshedsperth.com.au/garden-sheds

The roof will slide down on both sides from the centre ridge (rather than sliding the whole roof to one end of the shed, which saves a lot of space), eventually to be remotely controlled. I'll be working in my study, so the observatory only needs to be big enough to accommodate the equipment and it's arcs.

I found a formula for calculating the wall height at http://astronomy.mdodd.com/files/Cal...all_Height.pdf

"H elev = Tan(A elev) * D wall
EXAMPLE
Choose or measure A elev minimum desired or possible (if limited by trees) elevation (assume 25º)
Measure D wall distance from telescope center to wall (assume 60”)
Measure H scope height of telescope centerline above floor
Calculate H elev
Tan( 25º) = 0.466
H elev = 0.466 * 60
H elev = 27.96”
Wall may be 27.96” above telescope centerline height (H scope)
Add H scope to H elev for total wall height"


Problem is that formula puts the wall height way too high at 255cm. The image below shows my plan of the observatory in the shed with a wall height of 200cm, and includes the correct scale for the pier, mount and telescope. I'm probably looking at the lowest elevation of 25 to 30 degrees. So the wall height I image would need to be lower than 200cm.

http://130.95.21.121/pbrowne/Ob.jpg

Any advice welcome!

Peter