Before I had a
camera rotator, I used a machinists angle finder. I put it on a
machined surface of the mount's DEC dovetail and rotated the angle
to center the bubble. By using the vernier scale (on the back side
in the above image) the desired calculated new angle was set. Then I
put the angle finder on a corresponding camera housing surface and
rotated the camera to center the bubble. SBIG cameras usually have a
surface that is square with the chip. With this method I got
better than 0.25 degree accuracy. The accuracy was verified with a
plate solve.
This item is about 70
years old and may be hard to find, but digital versions are
available for about $30. .
