SV: ATM Altitude Bearing Angle

["Nils Olof Carlin" <nilsolof.carlin@swipnet.se>]

Rodger,

> I'm in the process of final assembly and have a minor question. I have
> semi-circular altitude bearings to mount to the mirror box. Looking at
> commercial dobs, their bearings are mounted anywhere from 30 to 45
degrees
> from horizontal when scope pointed straight up. Any ideas as to the
> variance? Any strong preferences ?
>
I use a cooking-pan bottom for semicircular bearings. By placing the cuts
at 45 degrees to the tube axis, I can have the teflon pieces at +-45
degrees
from vertical and get a full range from 0 to 90 degrees altitude (neither
end is of much use).

I canīt think of a reason for any other angle.

Melīs reply was for the angle of the teflon pieces from the vertical line,
I am not sure that was what you meant.

Anyway, if you have the same diameter of altitude and azimuth bearings, and
if the rocker box is 0.414 of the tube weight (not unrealistic), then
teflon pieces at 45degrees from vertical would give the same friction in
both motions.
A good reason IMHO for large altitude bearings.

Good luck with your scope.

Nils Olof