CPC800 Project scope or parts spare $300

[zimitsj]

CPC800 Project scope or parts spare $300

The MAS is selling the CPC800 that was in our loaner program. It has a broken corrector. It comes only with the broken OTA, the mount with the hand controller, the finder scope, tripod, and the JMI case. The selling price is $300.
Please contact Antone Gregory or John Zimitsch if you would like to see the scope, or purchase.

Antone Gregory: loanerscopes@mnastro.org
John Zimitsch: via PM

[SEmert]

Additional information, as I'm the one who examined it:

The corrector plate was smashed by the primary mirror falling down and hitting the corrector. All remnants of the broken corrector plate have been removed. The secondary mirror and assembly is intact and is included with the scope. The primary mirror is intact, but has a small scuff near one edge. It could be used as-is, as I don't think the scuff would have an appreciable impact on performance. If one were picky about it, the mirror could be stripped and recoated.

I did some research and, contrary to common opinion, the primary and corrector are not a matched set. A different corrector could be added. I could find no retailers in the US, but there are retailers in the UK and in France that sell corrector plates separately. Unfortunately, they don't sell/ship to the US. If you know someone in one of those countries, my thought is that they could buy one and ship it to you. In the US the only "official" method of getting the corrector replaced is shipping it back to Celestron for repair, which they can do. Price is determined after Celestron's inspection.

How did it get smashed? The primary mirror assembly is restrained from moving forward too far by an o-ring in a groove on the cylinder the primary moves on as it is focused. Someone tried focusing it too far forward, forcing the o-ring out of its groove. When the OTA was subsequently turned face-down to put it away, the mirror came crashing down.

The image John provided is the one that was used in its loaner scope web page description. The accessories that have been edited out have been reused with other scopes and are not part of the sale. What you see above (and what you partly see; the hand pad controller), are included.

[SEmert]

I just received my copy of the May 2024 Sky & Telescope. In the Astronomer's Workbench column on page 72 there is an article about taking one of the arms off the CPC mount to reduce it's bulk and weight, and adding a dovetail to the remaining fork. After which, the CPC mount can be used with an SCT ranging in size from a C5 to a C9.25, or even a refractor OTA.