Home built Refractor

I have decided to build my own refractor, probably starting with a D&G 6" cell. The question is where to go from here. Can those in the know point me to some resources that will help me with this project?

Hello Ed, good luck with your new project. I have built several refractors, the last one was with a 5 inch Ceragioli made achromat. If you are doing this as a learning experience and a fun thing to do it will be all that and more. If you are doing this in anyway to save money, I'd double check your calculations. A 72 inch or 90 inch refractor is a beast to use and mount. You'll need a nice (expensive) tracking mount and while you color correction for an achromat will be as good as they get, it won't be perfect on every object. After selling both of my projects for slightly less than I paid for everything, I now use a TEC-140. Assuming you are undaunted, I'd contact Hastings to get an aluminum tube or as I did on a couple of occasions made carbon fiber tubes from scratch (BIG job). Focusers show up on AM all the time, I used a 2.7 inch AP. Since I'm a binoviewer guy I cut the tube short and used an extension tube for single eye use. Getting the OTA together really isn't the big deal, once it's together you'll look at this big scope and see how substantial a mount must be to carry it well. Of course you won't want to skimp on the diagonal so a 2 inch quartz dielectric will be needed to take full advantage of the D&G achromat. Rings and dovetails are also easy to find at moderate expense but you'll need to decide on the mount before the dovetail is purchased. Flocking the inside of the tube or adding baffles is really going to be essential. Let me know what else you have or give some more design criteria and I can point you to some specific places for parts and help. You'll occasionally find used tubes here on AM, but chances are nothing as large or robust as you'll need. You'll want heavy tubing so nothing flexes.

George

Thanks for the input, my motivation is not dollars. I know I will be upside down but I plan on giving this project to my grandson someday far in the future. Since I made the post I have learned about Istar and have signed up for the Istar forum. I guess a first step would be to contact D&G and get a time estimate! I will continue to learn more about Istar and the quality of there objectives.