Backyard astronomy: a portable observatory.
One of the challenges of doing backyard astronomy in the big city is the fact that big cities are bright (see the telescopes I use here). There’s no such thing as dark skies in urban neighbourhoods. Coupled with a lack of space on a typical urban lot for a permanent observatory, it makes viewing challenging. Roll-off roofed sheds are popular where the location can be fixed, but many people like me need to move the equipment around to get clear views past trees and buildings.
Here’s what I came up with: A standard 9×9 tent, with the end screen panels removed and re-installed with zippers and a velcro latch flap at the top, to allow me to roll down the screening and stick the scope out. The tent mounts to a simple 2×4 frame with eye hooks and can be oriented in any fashion for viewing. The large rain canopy can be folded back loose around the scope to keep out stray light from the neighbour’s back porches and new streetlights the city installed (in the worst possible locations of course). Since West Nile virus arrived, it also helps keeps the mosquitos off me some in the summer. I just zip up the netting close to the scope and use the rain cover loose around the scope (or a black cloth I have as a head wrap), and a small heater can be stuck in there in late fall or early spring to keep the chill off enough, without creating heat eddies in my 10″ Dobsonian reflector. The whole rig keeps the dew off at night, and with the scope’s anti-dew heaters, I’m good for as long as I can stay awake.
The Schmidt-Cass pictured will rotate in enough to close it all over when I’m done. Judiciously placed small camping tables hold gear in various corners, in easy reach of the viewing position. A hanger strap at the apex allows me to hang a small red-light lamp to provide just enough light. There’s enough room for two scope setups comfortably, one out each end of the tent, or alternatively, with only one scope, there’s enough room to put down an air mattress and sleeping bag. During the day, I wrap the scopes in reflective silver mylar (“emergency blankets”) to reduce the heat buildup and the consequent cooling time in the evening. With the scopes wrapped and the tent fully closed over, its sufficiently rainproof to wait out a run of inclement weather. The tent will even tolerate a few inches of snow in the winter if its not too wet with water. A darker tent cloth would reduce ambient light better, but this works for the street lights and the porch lights, and it lets me leave the setup for a few days without exposing the equipment.