Detailed Deck Design

The dome on a SkyShed POD opens exactly halfway. This means that a telescope mounted in the exact centre of the dome would not be able to look straight up — it would be looking at the edge of the open dome. Any direction other than straight up can be accommodated by rotating the dome. The solution to this is not to locate the pier dead-centre in the dome, but to offset it somewhat.

Using some trigonometry I calculated that an offset of about 25 cm would give me the clearance I need while still keeping the OTA and mount parts clear of the dome and walls. SkyShed users recommend offsetting toward the direction in which you usually observe, since this leaves a little extra space for standing on the eyepiece side of the mount. For me I’ll be observing mainly toward the North (because my house is in the way to the South) so I planned to offset the pier 25 cm North of centre.

I also allowed a little room on the deck to change this centre offset by moving the dome, so I could adjust if I later discover some other arrangement would be better. By sliding the dome North, the offset could be changed to just South of centre.

Taking all this into account, I made up an overhead plan of how the dome would be situated on a 355cm-per-side deck, and where the pier would pierce the deck.