I'd like to build an 8"-10" OTA for high-power visual observing that I can mount on a GEM (G-11 or similar). I don't have a place for a permanent setup, so it needs to be reasonably portable. The G-11 head and tripod are each less than 40 pounds, and I don't want to go much heavier than that.
One option would be a Newtonian OTA. I don't want to tax the mount too much, so I'm thinking an 8" f/6 or f/7 would be about the largest Newtonian for this mount(?).
An alternative would be an 8" or 10" compound scope. I prefer open-tube scopes for faster thermal equilibriation, so I'm looking at either a Classical Cass or Dall-Kirkham here. Tak Mewlon is one option, althought the 10" is out of my price range. Also, I'd prefer something more optimized for planetary viewing, longer than f/12 and with a smaller secondary. Robert Royce is offering D-K optics sets, but I have no experience assembling or even collimating this sort of scope (been a Newtonian and small refractor guy).
Can anyone describe the difficulty of assembling a compound scope OTA, in comparison to assembling a Newtonian OTA? Does the compound scope need to be more rigid (guessing it's more critical to maintain collimation)? What sort of tubing, mirror holders, and rear end cap would be needed? Can this be done with only some basic tools, or does one need a machine shop for this project?
Thanks,
Duane
One option would be a Newtonian OTA. I don't want to tax the mount too much, so I'm thinking an 8" f/6 or f/7 would be about the largest Newtonian for this mount(?).
An alternative would be an 8" or 10" compound scope. I prefer open-tube scopes for faster thermal equilibriation, so I'm looking at either a Classical Cass or Dall-Kirkham here. Tak Mewlon is one option, althought the 10" is out of my price range. Also, I'd prefer something more optimized for planetary viewing, longer than f/12 and with a smaller secondary. Robert Royce is offering D-K optics sets, but I have no experience assembling or even collimating this sort of scope (been a Newtonian and small refractor guy).
Can anyone describe the difficulty of assembling a compound scope OTA, in comparison to assembling a Newtonian OTA? Does the compound scope need to be more rigid (guessing it's more critical to maintain collimation)? What sort of tubing, mirror holders, and rear end cap would be needed? Can this be done with only some basic tools, or does one need a machine shop for this project?
Thanks,
Duane
