Help with pinched optics

My Vixen 80SS I got last winter has always shown signs of "pinched optics". I had read that it's not uncommon for factories to overtighten lenses, and that colder weather can make it worse due to the aluminum housing contracting; but it hasn't gotten any better in the warmer months. I took out the lens cell to see if there were some screws I could adjust, but the lenses are held in place by a large (+/- 80mm) threaded ring with two tiny slots for a very special tool to grab. I'm afraid to go much further with trying it myself, but I'm having difficulty finding anyone who will work on it? Any suggestions?
P.S. I did call a nearby astronomy dealer who sells Vixen scopes, but since I didn't buy it there, they won't help me.

Brian Coltrane said:

My Vixen 80SS I got last winter has always shown signs of "pinched optics". I had read that it's not uncommon for factories to overtighten lenses, and that colder weather can make it worse due to the aluminum housing contracting; but it hasn't gotten any better in the warmer months. I took out the lens cell to see if there were some screws I could adjust, but the lenses are held in place by a large (+/- 80mm) threaded ring with two tiny slots for a very special tool to grab. I'm afraid to go much further with trying it myself, but I'm having difficulty finding anyone who will work on it? Any suggestions?
P.S. I did call a nearby astronomy dealer who sells Vixen scopes, but since I didn't buy it there, they won't help me.

Brian: I can understand your reluctance to try to loosen the ring as it is possible you might cause cosmetic damage to the slots. About all I can offer is to either contact your local astronomy club or maybe Vixen USA.

I would guess there are folks here who would be happy to help you but they just haven't seen your post yet...

Jon

Brian,

Because your lens is an ED and because it is the SS version, extra short, the curves on that glass are extreme. Normally, especially with a longer focus achromat, I'd just try loosening the retaining ring a bit. However, with this type of lens, if you loosen too much, then when you turn scope horizantally, ones lens might move in relation to the other. A problem. This can mess up color correction.

I understand your problem. While it's fairly easy to find someone who will do this sort of work on an achromat,,and honestly, not too difficult to do well yourself, finding someone (a professional?) who will touch anything other than an achro is not so easy.

Bruce

Hi,
I had a 80mm vixen Achro, I believe it was model # A80MWT. I had the exact problem you are referring to. I tried a few different things, even took it to a machine shop and they couldn't get the ring off either. What I finally did was, took the cell off of the tube and put the cell in the sun for about 15 or 20 minutes or so. I then carefully used a small screwdriver in the slot of the ring and it loosened right up and came off. I did put a very small amount of penetrating oil on the threads, and I mean a very small amount. I am not sure if the oil actually helped or not. I think heating up the cell is what really did it. If I am not mistaken, there was actually 2 rings. I had tried the loosening before with a screwdriver, even had another guy help me and we both tried with 2 screwdrivers at the same time and it still didnt work. Heating up the cell with the sun was the only thing that actually worked.
Also, after I got the cell apart, I cleaned the lenses very well, just in case any of the penetrating oil got on the lenses.
Contact me if you have any more questions.

Martin

Brian Coltrane said:

My Vixen 80SS I got last winter has always shown signs of "pinched optics". I had read that it's not uncommon for factories to overtighten lenses, and that colder weather can make it worse due to the aluminum housing contracting; but it hasn't gotten any better in the warmer months. I took out the lens cell to see if there were some screws I could adjust, but the lenses are held in place by a large (+/- 80mm) threaded ring with two tiny slots for a very special tool to grab. I'm afraid to go much further with trying it myself, but I'm having difficulty finding anyone who will work on it? Any suggestions?
P.S. I did call a nearby astronomy dealer who sells Vixen scopes, but since I didn't buy it there, they won't help me.

Martin has some good advice below. I would simply add that the "very special tool" used to be fairly common at larger full service photo shops. At 80mm on the objective, you are likely to be able to find one, or find a camera repair place with one that could unfreeze that retaining ring for you.