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Yet another trip to the timber merchants for more timber. I needed longer 2x6 material for the obs. floor joists to allow for the veranda. Because of twist and bend in the ordinary framing timber I chose the house building quality instead. I also bought enough 2x4 to add horizontal braces to the walls of the octagon.
My first worry was removing the upper rim joists to make room for the parallel joists. Would the structure move without these braces? It seemed it didn't. So I reattached them as high as possible, tight under the main beam's, timber support brackets. Just to keep everything in reasonable shape.
Now I could lift the new joists up and slide them back across the beams.
There followed much measuring as I tried to sort out the joist spacing. Having joists tight against the posts changed the spacing. A quick check of the drawing and I saw the problem. The outer posts aren't supposed to have a joist tight against them. Only the inner ones. Not that this is very important because the change is quite small.
The images show the joists arranged but not yet fixed with nails to the beams. I have donned the white safety helmet after banging my head on the new timbers as I climbed the ladder. I shall leave the beams and joists overlong until everything is fixed before cutting them to length to fit the rim joists.
I'd like to get something to stand on up there so I can fix braces between the tops of the posts. These have to be fixed from outside the structure and there is nowhere useful to rest a ladder yet. So I'll need to stand on the veranda to reach this area. It's not worth the risk to try fixing these braces until I have somewhere safe to work from.
I spent some time wondering about a suitable width for the trapdoor/hole in the floor. It's not just a matter of my squeezing through. So much as the need to pass potentially large or long instruments up through the hole. Rotating the "dome" slit over the trapdoor will provide more pace above if needed for [say] a long refractor. How large an object is likely to need much space?
The length of the trapdoor is very adequate at 117cm between the beams. So only the width becomes important. Should the trapdoor be made wide enough for a much larger [surprise] visitor than myself? In the end I fixed a piece of 2x8 below the joist which sets the width for the pier aperture. I'll think about adding the other side when the need arises and the rest of the joists are fixed. Some shorter joists are needed where they butt against the trapdoor frame.
Now I could lift the new joists up and slide them back across the beams.
There followed much measuring as I tried to sort out the joist spacing. Having joists tight against the posts changed the spacing. A quick check of the drawing and I saw the problem. The outer posts aren't supposed to have a joist tight against them. Only the inner ones. Not that this is very important because the change is quite small.
The images show the joists arranged but not yet fixed with nails to the beams. I have donned the white safety helmet after banging my head on the new timbers as I climbed the ladder. I shall leave the beams and joists overlong until everything is fixed before cutting them to length to fit the rim joists.I'd like to get something to stand on up there so I can fix braces between the tops of the posts. These have to be fixed from outside the structure and there is nowhere useful to rest a ladder yet. So I'll need to stand on the veranda to reach this area. It's not worth the risk to try fixing these braces until I have somewhere safe to work from.
I spent some time wondering about a suitable width for the trapdoor/hole in the floor. It's not just a matter of my squeezing through. So much as the need to pass potentially large or long instruments up through the hole. Rotating the "dome" slit over the trapdoor will provide more pace above if needed for [say] a long refractor. How large an object is likely to need much space?
The length of the trapdoor is very adequate at 117cm between the beams. So only the width becomes important. Should the trapdoor be made wide enough for a much larger [surprise] visitor than myself? In the end I fixed a piece of 2x8 below the joist which sets the width for the pier aperture. I'll think about adding the other side when the need arises and the rest of the joists are fixed. Some shorter joists are needed where they butt against the trapdoor frame.
Click on any image for an enlargement.
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2 comments:
Really enjoying reading your updates every day. I am impressed that you find the time to sit down and write your blog. Cannot help thinking that if I build a similar elevated observatory for my 12 inch fullerscopes newt on a mk 1v mount that I will probably build the base under the observatory floor from silcon breeze blocks and avoid alot of that timber!.
Hi
Thanks for your interest in my strange activities.
Good to hear somebody is still using Fullerscopes equipment.
The choice of timber, concrete, or blocks was a personal one based on my limited set of skills. The observatory needed to be easily removable back to [literally] bare ground. And, hopefully, completely non-heat absorbing. Anything made of heavy materials is apt to release heat long after the sun goes down. The seeing is already bad enough here without my adding to it. I am still hoping the raised platform will lift me above the worst of the seeing. As well as showing me a lot more sky, of course.
Thanks
Chris
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