SW 12" ota circumference?

[paul mc c]

Would any one know the circumference of this ota please.

Thanks Paul

[Thalestris24]

Hi

Sorry, I can't be precise but c = pi x d, so my calculator says c = 38", rounded up

[ronin]

But the OTA has a bigger diameter then the 12" mirror inside it.

Suggest you add 1" either side making 14" and start with that which is 44", but that is a guess and could be more depending on what space they have either side of the mirror simply  as the mirror sits in the cell and that has to go in. I would guess you are looking at a 15" or 16" diameter tube.

Someone here must have a 12" to measure the diameter and post it.

[Tinker1947]

I have a 12" Dob, i need a cuppa tea before venturing out in the fresh air, 20 minutes from the is post and i will have the measurement...

Its 360mm that's a 1/8" over 14"

[russ.will]

Would any one know the circumference of this ota please.

Thanks Paul

Do you mean the steel tube, or the cast rings? Are we talking an Explorer, Skyliner or FlexTube? More importantly and this may help guide answers - Why?

I can tell you the inside diameter of the cast rings is 342mm from when I was making internal light shrouds, but from memory the top ring adds another 8mm (2x4mm) to the outside diametre. I believe the top ring is the same on all variants. That gives a external circumference of 1100mm, but depending on the material used to surround it (assuming that's what you're doing) you may need to under-size stretchy material slightly to ensure a good interference fit.

Russell

[paul mc c]

Sorry i should have stated which scope,it is the 300p,it is not my scope but i think the fella is getting slip rings made,the measurements are of the actual tube.