The Blaber Observatory: a "Roll-off roof" design

Some construction photos (note Penny, my faithful dog):

The completed observatory (more or less…):


People usually associate a traditional observatory building with a dome roof. You can buy these for a home observatory, but they are very expensive. The purpose of a home observatory is to allow permanent installation of a telescope with protection from the elements, and yet allow access to a reasonable expanse of sky, while shielding the observer from stray light. Essentially you want a simple and reliable way to remove and replace the roof. The "roll-off" roof design pretty much meets all these requirements. There is a support structure on one side of the building that the roof can be rolled onto.

The observatory is 8' x 10' with 7' high walls. The walls block out ambient neighborhood light, but allow access to most of the sky. I designed the location of the observatory so that natural obstructions to visibility follow the top of the walls. These obstructions include the house roofline to the south, and trees and neighbor rooflines on other sides. The observatory roof is designed with low pitch so that it doesn’t block much of the sky, and the support structure is on the west side, because we have large trees there (which end up blocking more of the sky than the roof. I cut down two large oak trees that were in the way (you can see where one was in the round brown patch in some of the photos). I told my wife I had bad allergies to oak trees and they had to go.


The homeowner's association requires that outbuildings be finished in the same material and color as the house. Our house is stucco, so I had to stucco the exterior of the observatory. I have absolutely no idea how to do stucco. It is like trying to smear wet sand on a vertical wall (actually, it is smearing wet sand on a vertical wall). The white stuff on the ground around the observatory in the photo is after cleaning up stucco that never quite stuck to the walls and fell off. The first wall I tried took 5 bags of sand and stucco mix. The last wall took 1.5 bags, so I got better.

The roof is on wheels and rides an aluminum channel. It's not the best design, but works so far (with a lot of noise and effort). It is opened with one winch and cable, and closed using a different winch. All cables and hardware are located inside the observatory.

The observatory is wired for several lights and outlets. I have a PC with a wireless network to the PC's in the house and to a cordless modem. The telescope is computer controlled, as is the CCD camera that is used for guiding or for taking small images. I can download these images to my PC in the house.

I paneled the interior and put down linoleum tile to make it comfy (and also to prevent being poked by one of the billion nails poking through the exterior sheathing).

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2001 Michael Blaber