I have been considering rebuilding my 12 inch dob in an effort to reduce weight and please my eq6 mount
. Also my perceivement
of the reduction of flex is appealing.
One idea was to cut the tube approx in half relace the secondary with a flat surface primary mirror parrallel to the primary of approx 6 inch dia. and drill a 2.5 inch hole in the primary so focus would occur in the camera mounted behind (outside) the primary.
The mirror needs a resurface so it has little value
.
I dont fear the loss of light in using a 6inch secondary (or down to a 5 inch)as the surface area left means I would have around the equivalent a 10inch (a little more probably) which would be great for photos.
All visual tracking will be thru a separate guide scope.
Perceived advantages 1. the tube would have less flex and
2.less heavy than original.3 More easy to manage and transport.
I hopefully expect that it would be inexpensive as the real cost would be in getting the hole drilled and getting a 6 inch secondary (would like unbevelled sides but at worst would lose 1/4inch to frame a conventional secondary).
Why should I give this idea up what have I missed
? Can such a hole be drilled either at home or professionally in Australia.
Will the new optical path work?
Any suggestions gratefully received.
alex