Ad Astra Observatory

I am trying to source the plywood for the project, so I asked a local wood guy if he could get some 5/8” Birch ply…

Sorry for the delay in getting back to you but 5/8” is hard to come by and it took a while to track some down. I can sell half sheets of 1/2” or 3/4” but for the 5/8” I can only sell full sheets. A full sheet is $101.97.

I do have 1/2” and 3/4” Finnish Birch and Apply Ply in stock if either of those would work for you and as I said can sell 1/2 sheets of those.

Maybe you can help me decide between 1/2” and 3/4”. I’m putting together a Plettstone/Highe style mirror box (that’s 2 plywood rings with aluminum tube standoffs, much like the upper cage of an Obsession) for a
13.1” mirror that I picked up off of Astromart. I’d like to keep the mirror box as light as possible, because my plan is to mount the scope on a G-11 GEM mount.

After going to to a local-hardware-store-that-will-remain-nameless, I think that 1/2” will probably work Do you think it will hold up, or do you think it will be too flimsy? I need to get my hands on the mirror to
be sure, but I think it’s a thin one — the seller said it was only 1” thick. I’m trying to keep the weight closer to 25 pounds than 35.

Anyway, I also figured out that I can get the whole job done in a quarter sheet of ply, although if I have to buy a half sheet, that will give me enough extra to do stuff like dust covers, etc.

Is Apple a little darker than Birch? Is it heavier?

I may (still haven’t figured this part out) need to build some split blocks to hold the tubes in place. Do you stock any dimensional hardwood? I was thinking that I would need to end up with 2” cubes, but
I suppose a chunk of 2×4 would work.

Also, I keep meaning to ask you; where did you get the (carbon fiber?) tubes that you used with your 8” scope? The 13” scope will actually be about the same focal length, so if I need to really crank down on
weight, I’m thinking about (re-) building it up into a string scope.