Since about May 2003, I have been thinkin about how to build an observatory in my back yard. Somehow, it was clear to me from the beginning that I wanted a roll-off roof hut, a dome was out of the question. The reason was that I heard lots of bad news about domes - not enough air circulation was the major one. Plus: I can build a roll-off roof hut myself (I think...).

How big?

Luckily my old 6" Refractor is pretty much the same size as the new 16" Cassegrain. I set it up and put wood on the floor to find the minimum space I need. It turns out to be 250 cm by 250 cm. In the end I decided that I want 280 cm x 350 cm - just a bit bigger to have some margin, plus room on one side to allow for a chart table. In the end I decided to add a little seperate room to house computers, monitors, and myself. The idea is that this room will be insulated and can be kept warmish. In the end the ground floor size is 280 cm by 500 cm.

Modifying a commercial garden hut or building it from scratch?

I discussed readly available garden houses ("tuin huisjes") and self-built ones. I looked at a zillion of web pages and back issues of "Telescope Making" to 1980 (23 years ago!). The conclusion was: I have to build my own house! Why? I found special wooden logs for garden huts in the nearby do-it-yourself store and decided to go for it (in the end I did not go to the do-it-yourself shop, but decided for a special wood dealer, see

The only problem was: I did not dare to anchor the house in the ground myself. My gardener solved the problem. When asked about "how do I make sure the house doesn't go down the slope to the channel behind my lot" he said "why don't I build a platform for you?" - I immediately agreed to that. He builds the grounds, I do the rest. He had asked me for a ground plan, which you can see here (don't trust  my Dutch spelling). It is not the final drawing - really the door is now in the middle, and there is another window to the right.

klick to enlarge (350 kB)

Note that I will orient the hut approximately east - west. Normally people say you should orient it north - south. Well, if I did that it would stand too much into my garden. And I couldn't really think of any disadvantages anyway. To the east, where the roof goes when observing, there is a huge tree blocking the view anyway, so not being able to point low makes no difference anyway.

This page created by dvk, 10 Oct 2003 - last update 05 Jul 2004.
Return to Koschny's Astronomy.