Mistakes I made in building my observatory

stellar2 · #1 20-01-2006, 03:44 PM

Trying to keep costs down, I used as my original observatory a commercial shed about three metres square made of zincalume. First, of course, I had to sink a pier for the heavy mounting I planned to buy. That was straightforward; a large hole, a length of concrete pipe, a quantity of reinforcing steel, and a load of cement. I assembled the shed around it, resting on short piles made of treated pine. This was in my grassy back yard.
I rebuilt its roof as a roll-off, with large rubber-tyred wheels running in extruded aluminium track fixed to timbers. This structure worked well, but was uncomfortable in the Canberra winter, as the temperature inside went severl degrees below the outside (already freezing!) temperature on clear nights. I decided on a fibreglass dome which, with its amaller observing opening, would be less frigid to work in. I'd worked in domes at Mount Stromlo for fifteen years.
The dome was lifted on to a new, flat roof with a circular aperture, and always worked well. It was certainly less windy and cold inside!
But there were two things wrong. The piles on which the shed's frame rested were too close to the grass. And the flat part of the roof was never able to keep out rain. It always leaked at the joints, no matter what I tried to seal them with.
As a result, water got into the floor supports and also the particle board flooring I had fitted (with carpet on top) and before I knew it the floor and the joists collapsed as their timber had begun to rot. I don't have either the energy or the funds to rebuild, but I have to say, avoid flat roofing as it is not possible to make it waterproof! A dome needs to be on a circular wall. A plastic water tank might be good. Floors need to be at least 20 cm above the ground.

Miaplacidus (Brian) · #2 20-01-2006, 03:57 PM

Well, if you ever want to try again to make it perfect, I've got a block of land you can put it on.

h0ughy (David) · #3 20-01-2006, 04:18 PM

any pictures of your observatory?

lorenz117 · #4 28-01-2006, 11:17 AM

Sorry to hear about that - did you find the roll-off roof was better in the waterproofing sense? What type of dome did you have? I'm tossing up between the two at the moment

stellar2 · #5 29-01-2006, 08:22 AM

Quote:

Originally Posted by lorenz117

Sorry to hear about that - did you find the roll-off roof was better in the waterproofing sense? What type of dome did you have? I'm tossing up between the two at the moment

My roll-off roof was perfectly waterproof, but the interior was freezing cold in winter - see my thread about 'mistakes in building'. I bought a Sirius Dome, which worked perfectly and still does. But the join between the flat part of the roof and the dome was never perfectly waterproof, nor were joins in the flat part of the roof. Any builder or architect will tell you flat roofs are almost impossible to waterproof. The dome is for sale to anyone who wants to buy (and transport) it. Make an offer! I have photographs of both versions of the roof, but cannot get Iceinspace to accept them, as they seem to be in the wrong format, even though in Photoshop I convert them to JPEG. Views of observatory: I use a Macintosh; none of the 'valid file types' are available on my machine.

lorenz117 · #6 29-01-2006, 10:21 AM

Mike is that you? It's lorenz - we exchanged a couple of emails via AM a while back. I'd still be interested in your observatory, but I though you were taking it to sunny QLD. Send me an email if you like

rowena · #7 08-02-2006, 03:51 PM

I think i saw your advert on Gecko Optical!... So if anyone wants a squiz there is a pic on there! if your the same person!. (I dare say you are!

)

Robert_T · #8 08-02-2006, 05:00 PM

..my first observatory was a paper mache dome (no I'm not joking) that I sealed and painted with white enamel and it was amazingly water-proof. The dome was seated on a a circular rail upturned on wheel supported on the circular besser brink walls. The dome slightly overhung the walls and I ran some flashing down the outside overlapping the walls for about 15cm. Only the wldest storms could push any water in.

cheers,

stellar2 · #9 20-02-2006, 10:51 AM

Lorenz bought my Sirius Dome. When we dismantled it all parts were working perfectly, after about 10 years' exposure to the elements. the only wear was on the rollers of the up-and-over shutter, and they still worked perfectly. So if I was asked about the reliability of this astronomical product, I'd have to say it's excellent, and if you want a commercial dome I'm sure you couldn't do better. Go for dome!