Posts Made By: Brian Coltrane

Just purchased a used Vixen 80SS that I plan to piggyback on my AR-5. I don't know that I can use the typical mounting ring approach since the OTA is so short, and the dew shield retracts over most of the body. The scope comes with a built-on VXN dovetail. Is there a female dovetail rail that I can mount to my AR-5 to accept the 80SS that can be adjusted to align the piggyback with the main OTA?

Just picked up a used Vixen 80SS as a 2nd scope. Just had first light - not the greatest conditions and not much time, but couldn't wait. Read great reviews about this scope - some even calling it a "semi-apo". So, I was surprised at how pronounced the red CA was. No violet noticeable, but red still there even with Baader fringe killer. Is red CA an indicator of something that needs adjustment?

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.

I've had newts & refractors. I still love my apo, but I'm looking for a compact scope with about 8" aperture for a dual mount setup (all visual, no AP). One thing a didn't like about my newts was the coma problem. I'm hoping to find a good deal on Astromart. Any advice as to what I should be going for??

Well the clouds & rain finally broke last night so I got a chance to try out my C8 for the first time. I've got it on a dual saddle mt. with a W.O. Megrez 90 on an LXD75 GEM. Let me just admit that I've found myself starring at the setup in my garage during the never ending cloud cover the past few weeks - it just looks so cool. I'll try to get some images to post if anyone's interested.
Based on the advice of others, I took it outside an hour ahead of time to let it cool down. I strapped a "Reflectix" car windsheild screen around the end of the OTA as my dew shield. I had a Celestron F/6.3 reducer screwed into the rear cell as recommended by Uncle Rod and my preferred 2" diameter VB.
The collimation looked spot on - no adjustments needed. So, I went straight to some viewing. The scope had equalized pretty well by this time. There was no apparent "boiling" except for brief intervals after slewing to another part of the sky. I think that the long dewshield may have been trapping some mixed temperature air and it was getting stirred. I think I have a fix for this and it really wasn't a big deal.
The views in the SCT are definitely less contrasty than the refactors I've used, but their pretty darn good. The complete lack of CA is nice, and I did not detect the coma issues that bothered me with my old Dob. The extra aperture really helped on DSO's and some dimmer star clusters. Jupiter may have had some more detail but was definitely more pale - but still pleasing. Some filters would probably help increase contrast.
All in all, I was very happy. The dual setup is really the way to go. Having the high contrast wide field view with the M90 right there with the C8 gives you the best of both worlds in a very manageable setup. You can easily move your eye from one scope to another to observe each object and allow your brain to combine the best attributes of each scope to synthesize a better overall picture. Sure, I'd love to have a giant APO which would give better views of everything - but I can't afford it, nor do I have a permanent pier in a observatory to keep one. So until I win the lottery. This will have to be my "dream" setup.
CS, Brian