EQ mounting a reflector question

[loki78 (Jon)]

Quick question, when mounting a larger reflector (in my case an 8" F6) is there any hard and fast rules about how far apart the tube rings go which obviously dictates what bar you put it on.

It's a fairly long tube so I would imagine you would want a good spacing for stability and then put it on a long bar.

But really, I'm not sure how it's generally done.

Anyone?

[Astro_Bot]

A longer dovetail bar allows more flexibility in balancing the OTA on the mount, though there is a slight weight penalty.

Some bright spark of a mechanical engineer out there could probably calculate the optimum ring spacing given stiffness and weight distribution, but the effort mightn't be worth it.

Have a look at a few photos to see how other Newtonian OTA's have been successfully mounted - that'll give you an idea.

[2stroke (Jay)]

Just using a 13" with our F5 8" and have the rings one at each end. I havent really used it much to make comment on flexing but its not that much of an issue with a 8" unlike a 10" or 12".