This tread was inspired by JP50515. Thank you.
I hope my experience may help some of astronomers who have "special neighbors" and must obey local building codes.
Here is my solution of my first "observatory". Frame was built from 1" PVC pipes and fittings for plumbing.
To make frame more rigid I inserted inside PVC 3/4" EMT electrical conduits. That was done before assembly PVC pipes and fittings. Surprisingly it made frame MUCH less flexible with addition diagonal tension wires. I covered frame with custom sewed tarp. Silver side of tarp reflected more UV light and last 3 seasons, but now has sign of weather deterioration and no longer in use. Beneath tarp was one layer of polyethylene film as second protective water barrier. Front of "shelter" has 3' vertical zipper. It made possible to open this shelter. Along one side frame was fixed to deck with hardware allowing rotate frame.
Overall construction was Do It Yourself project, cost efficient and quick to open/close observation session. Local code enforcement officer had no objectives .
Thanks for watching.