Not done it before but I like the idea, would you be cutting the top off to make it rotatable? I reckon that would remove a lot of strength and the walls would then flex a lot, so would likely need a ring of some sort around the rim, which you would likely need for running wheels anyway.
What are the diameters of the tanks shown?
the second picture there looks like a poly tank from Mastertanks in Adelaide. The 5000L (which I actually had in my garden when I lived there) is 1.8m in diameter, and 2.05m high.
Everytime I drive in the bush past one of these big water tanks I'm thinking the same thing. The big ones can be quite expensive though. When you think about it you'd only need the top part.
Cut the aperture for your scope but rather than cutting the top off the tank, cut all but the outside 150mm of the floor out and have the whole tank rotating, much stronger, less chance of water getting in the top and any water that gets in will then go out the bottom. Then you can have your bearing surface on a slab of concrete and the whole tank held down by L brackets.
Everytime I drive in the bush past one of these big water tanks I'm thinking the same thing. The big ones can be quite expensive though. When you think about it you'd only need the top part.
I like the Idea of having a complete seal around the bottom for bugs and dust.
Cut the aperture for your scope but rather than cutting the top off the tank, cut all but the outside 150mm of the floor out and have the whole tank rotating, much stronger, less chance of water getting in the top and any water that gets in will then go out the bottom. Then you can have your bearing surface on a slab of concrete and the whole tank held down by L brackets.
You will also need a door hatch of course.
A bit like Zane's Observatory only not so round!
Hi Matt,
Good point about strength being on the bottom good for centre of gravity as well but how to seal for bugs. (on top)I was going to put a outside flashing for bad weather.
Cut the aperture for your scope but rather than cutting the top off the tank, cut all but the outside 150mm of the floor out and have the whole tank rotating, much stronger, less chance of water getting in the top and any water that gets in will then go out the bottom. Then you can have your bearing surface on a slab of concrete and the whole tank held down by L brackets.
Good point about strength being on the bottom good for centre of gravity as well but how to seal for bugs. (on top)I was going to put a outside flashing for bad weather.
Den
When I first came to Aus, in 1961, I rented a house in Hope Valley, SA that had a homemade 14" in a metal observatory. The obs. rotated on rails at the base and the builder kept the bugs out by having a 240v live rail under a flap all around the base! Worked very well!!
When I first came to Aus, in 1961, I rented a house in Hope Valley, SA that had a homemade 14" in a metal observatory. The obs. rotated on rails at the base and the builder kept the bugs out by having a 240v live rail under a flap all around the base! Worked very well!!
Charles
I wonder if you could use 12V like a electric fence only using a quicker pulse rate.
I would be very cautious about using watertank instead of proper dome.
The problem will be when the opening is cut - the tank supporting structure (actually, there is none) may collapse and you may end with wobbly and useless pile of plastic.
Instead, we (I am also considering all sorts of options for my future observatory) may try to talk Col into manufacturing some more of his very interesting 2.4m or 3m metal dome http://www.astrodomes.com/ (he is looking into retirement right now and the availability of his products is pending on sale of the business).
Geo-dome approach is also very interesting one.. I am looking into sourcing the criitical elements of the construction, mostly the connectors, like in attachment (5-way connector is shown, 6-way is also needed for 3V dome.. something like on other attachment.)
Playground using Water tanks Strength in door area.
Quote:
Originally Posted by bojan
I would be very cautious about using watertank instead of proper dome.
The problem will be when the opening is cut - the tank supporting structure (actually, there is none) may collapse and you may end with wobbly and useless pile of plastic.
Instead, we (I am also considering all sorts of options for my future observatory) may try to talk Col into manufacturing some more of his very interesting 2.4m or 3m metal dome http://www.astrodomes.com/ (he is looking into retirement right now and the availability of his products is pending on sale of the business)
Here is a playground built with tanks, it uses metal to help support weak areas. eg flat bars & angle on door frames. It was very strong and roomy.
Well, maybe this is OK for playground, but our dome must rotate as well. So there is no support on the lower part.
Also, cut needed for astro-dome is longer (zenith!)
My point is (probably 2c worth or even less), that it may prove to be more expensive to try and adapt the watertank, than building something more suitable from the scratch.
I would be very cautious about using watertank instead of proper dome.
The problem will be when the opening is cut - the tank supporting structure (actually, there is none) may collapse and you may end with wobbly and useless pile of plastic.
Instead, we (I am also considering all sorts of options for my future observatory) may try to talk Col into manufacturing some more of his very interesting 2.4m or 3m metal dome http://www.astrodomes.com/ (he is looking into retirement right now and the availability of his products is pending on sale of the business).
Geo-dome approach is also very interesting one.. I am looking into sourcing the criitical elements of the construction, mostly the connectors, like in attachment (5-way connector is shown, 6-way is also needed for 3V dome.. something like on other attachment.)
Nice brackets, depending on how much they are I had a similar idea a while back using triangle brackets spread around evenly on a round plate. (see picture). I can weld this my self.
Nice brackets, depending on how much they are I had a similar idea a while back using triangle brackets spread around evenly on a round plate. (see picture). I can weld this my self.
I love those Geodesic dome kits, You could rotate the base on some aluminium angle on concrete.
Instead, we (I am also considering all sorts of options for my future observatory) may try to talk Col into manufacturing some more of his very interesting 2.4m or 3m metal dome http://www.astrodomes.com/ (he is looking into retirement right now and the availability of his products is pending on sale of the business).
I have a 3m metal Astrodome, I think it was the last one that Col manufactured.
They are very good.
A little more expensive than a tank conversion but well worth it.
Dennis if you wanted to come and have a look and get some ideas, I am in the Canberra region, feel free to contact me.
Everytime I drive in the bush past one of these big water tanks I'm thinking the same thing. 
The big ones can be quite expensive though. When you think about it you'd only need the top part.
