Vintage C8 from ASSNE Surplus Equipment Purge

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Chuck
Posts: 281
Joined: Tue Mar 31, 2015 1:14 pm

Re: Vintage C8 from ASSNE Surplus Equipment Purge

Unread post by Chuck »

Mike, great report and job getting the old Celestron back in working order. Just curious, did the corrector plate have alignment marks on the outside edge for when replacing it in the front cell? Thanks for sharing.

--- Chuck
Chuck M.

Meade 8" LX200 Classic OTA
iOptron CEM40EC and MiniPier on Meade classic field tripod
Canon EF 200mm f/2.8L II
Canon 7D Mark II
ZWO 60mm f/4.6 GS with ASI120MM-S camera
Starizona SCT Corrector II and Virtual View 2" Rotating Visual Back
Pegasus Astro Pocket Powerbox
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Apollo XX
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Joined: Sun Jul 11, 2010 8:11 pm

Re: Vintage C8 from ASSNE Surplus Equipment Purge

Unread post by Apollo XX »

Chuck wrote: Thu Apr 21, 2022 6:50 pm Mike, great report and job getting the old Celestron back in working order. Just curious, did the corrector plate have alignment marks on the outside edge for when replacing it in the front cell? Thanks for sharing.

--- Chuck
Hi Chuck,

The corrector did not have orientation marks, and in fact I'm pretty certain it had been out before, at least judging by the 'tilt' of the secondary holder and the serial number tag relative to the orientation of the altitude axis'. If you look at most fork mounted SCT's the three collimation screws on the secondary usually make an upright triangle, and the base of that triangle is typically level across the DEC pivots. In my case the base of the triangle (and the serial number tag) had a definite tilt to the left. Another clue that it was skewed was in the location of the corrector plate serial number, which in the case of the ones that I've seen is aligned with the 90 degree point on the right side when looking at the scope face-on. Again, this was also skewed up to the left.

C8.jpg
C8.jpg (493.8 KiB) Viewed 67 times
She's listing to starboard, Captain, DO something! :D

When I installed the plate I re-established the level orientation, perhaps more as a matter of aesthetics more than anything else. Post-cleaning images are as good or better than pre-cleaning, and a quick gander at the collimation showed no gross changes to the star test image.

Squeaky Clean.jpg
Squeaky Clean.jpg (78.6 KiB) Viewed 67 times
Living on the level now, and it feels so good. :lol:

Mike M.
"The purpose of life is the investigation of the Sun, the Moon, and the heavens." - Anaxagoras
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Apollo XX
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Joined: Sun Jul 11, 2010 8:11 pm

Re: Vintage C8 from ASSNE Surplus Equipment Purge

Unread post by Apollo XX »

So you know how Google and YouTube are tracking everything we do on the internet and then they 'tailor' things to suit the preferences of the viewer? Well I was on YouTube this morning looking at something completely unrelated, and this popped up in the sidebar;

https://www.youtube.com/watch?v=nqh1TwO1DPk

I found it interesting given my most recent adventures with the old C8.

Mike M.
"The purpose of life is the investigation of the Sun, the Moon, and the heavens." - Anaxagoras
Chuck
Posts: 281
Joined: Tue Mar 31, 2015 1:14 pm

Re: Vintage C8 from ASSNE Surplus Equipment Purge

Unread post by Chuck »

Hi Mike:

Interesting info/background on the C8 corrector plate orientation. I had asked the question because when cleaning the corrector on my circa 1992 Meade Classic LX200 8" SCT, there were alignment marks on the edge of the corrector and front cell it sits in. Based on your tests, it looks like you reinstalled it perfectly.

When I cleaned the corrector and primary mirror, I hadn't used the scope for over 15 years. The first time I used it after that long hiatus, it powered up and seemed to be okay, but after a few more attempts the electronics went haywire and it started acting like the robot from 'Lost in Space'. At that point, I deforked it and put it on a Celestron AVX. I then found another issue when focusing, slippage of the primary mirror on the internal drawtube. Until I decide to regrease the drawtube, the issue has been resolved by occasionally running the stock focuser through its whole travel, in and out, several times during the time it's used each year.

BTW, I watched the youtube video you linked and it was quite interesting. Thanks for sharing.

--- Chuck
Chuck M.

Meade 8" LX200 Classic OTA
iOptron CEM40EC and MiniPier on Meade classic field tripod
Canon EF 200mm f/2.8L II
Canon 7D Mark II
ZWO 60mm f/4.6 GS with ASI120MM-S camera
Starizona SCT Corrector II and Virtual View 2" Rotating Visual Back
Pegasus Astro Pocket Powerbox
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