My 8 inch f/2.9 rich field telescope refurb project
Posted: Mon Aug 14, 2023 2:03 am
Some of you may have heard this story before. I was seduced from a small ad in Sky & Telescope some time around 1979, and I ordered and bought an 8 inch f/ 2.9 reflector with a front optical window as my first "big" telescope after receiving a brochure in the mail that I requested from the Sky Research company. Here's part of the brochure (now a little defaced):
Five long months after I ordered it, I received the scope, and I was amazed I could see thousands of stars through it that I couldn't see with the naked eye. It was great until I realized it needed a little tweaking in the alignment. I was shocked to find out there were no adjustment screws for the main mirror and the secondary was mounted in the center of the optical window, also with no adjustment screws. Sky Research was not answering my calls, so I took the scope to a local telescope shop in Tucson called The Image Point. A guy named Pierre that created the Big Foot Mount, and later his own telescopes, tried to pry the glued-in optical window apart from the tube, accidentally cracked the optical window. He offered to build me a spider and diagonal holder and that seemed to improve the performance of the scope somewhat. Here are pics of what the scope looked like before and after the optical window broke. The last pic is what the scope looked like without the optical window. The first pic is not my scope, I would never let the window get that dirty!
In 1993, I decided to re-design the scope; my firstATM project. I made the mistake of making the tube too long and it was quite top-heavy (the Telrad didn't help!), but a great light deflector. I also swapped out the focuser with a simple helical focuser, another mistake IMO because it did not have a fine enough focus to it.
A few years ago, I decided to refurbish: shorten the tube, strengthen the focuser area (by using a technique recommended from a fellowATM person on another forum) using an extra inside layer of cardboard tube located inside the main tube, then repaint it inside and outside, upgrade to a 2 inch JMI Crayford focuser, refigure (if needed), and recoat the mirror, and get rid of the Dobson mount. Well, I obtained a JMI 2 inch crayford focuser (not shown), strengthened the focuser area (shown in the 2nd and last pics with focuser hole not cut out yet), and completely repainted the tube and end rings, but that's about it. I have lots of work to do, but I'm hoping I can join a local ATM club that can help me finish it! Here are the pics:
Five long months after I ordered it, I received the scope, and I was amazed I could see thousands of stars through it that I couldn't see with the naked eye. It was great until I realized it needed a little tweaking in the alignment. I was shocked to find out there were no adjustment screws for the main mirror and the secondary was mounted in the center of the optical window, also with no adjustment screws. Sky Research was not answering my calls, so I took the scope to a local telescope shop in Tucson called The Image Point. A guy named Pierre that created the Big Foot Mount, and later his own telescopes, tried to pry the glued-in optical window apart from the tube, accidentally cracked the optical window. He offered to build me a spider and diagonal holder and that seemed to improve the performance of the scope somewhat. Here are pics of what the scope looked like before and after the optical window broke. The last pic is what the scope looked like without the optical window. The first pic is not my scope, I would never let the window get that dirty!
In 1993, I decided to re-design the scope; my first
A few years ago, I decided to refurbish: shorten the tube, strengthen the focuser area (by using a technique recommended from a fellow
Ouch, too pricey for me! Hmmm.....I think I'm going to re-think the tube. I may wrap the tube with carbon fibre vinyl wrap, clean up the end rings, paint them red and get a red tube ring assembly. It'll be like a pseudo-Sharpstar Newtonian!