Performance Modification Video for an Edge SCT

[curtisca17]

One year ago my friend Dave decided he wanted to improve the performance of his Celestron 11" Edge SCT for astrophotography.  His main motivation was to see if he could reduce mirror flop which is a well known problem with SCTs.  He had read on CN that someone installed nylon screws between the outer and inner baffle tubes to reduce the play between the tubes and minimize mirror flop.  This was his primary objective of the modification, but he decided that he should perform other modifications while he had everything apart.  In total, Dave made the the following modifications:

1.  Added nylon screws to the baffle tubes to try and minimize mirror flop

2.  Added internal fans and deflectors to direct the air flow over the front of the primary mirror to break up the air

3.  Added a temperature sensor on the back of the mirror

4.  Replaced the stock grease with a much better Krytox lubricant

5.  Flocked the inside of the tube

I jumped at the chance to help him since I also own an 11" Edge (and 6" and 9.25" SCTs) and decided to video the entire process including disassembly as well as the mods.  I previously posted a separate video showing the entire tear down process step by step.  A link to that video is shown below for anyone wanting to see how easy it is to disassemble an SCT.

In the process of tearing the scope down Dave noticed that the hardware included with his Celestron motorized focuser did not fit correctly allowing for excess play in the mirror assembly leading to additional opportunity for mirror flop.  I found the same issue on my Celestron motorized focuser as well.  In my case I experienced binding of the focus motor on several occasions which is a problem that has been reported by many others.  So we came up with two options to fix the problem and I made that into its own video as well.  Again, the link is below.  It appears that Celestron finally figured this out and corrected the problem recently, but if you own an older SCT and use the Celestron motorized focuser you might want to take a look and see if you are subject to the same issue.

Now a year has passed and Dave has had an opportunity to see how his improvements performed.  So we just shot some additional video as a follow up to the modifications where Dave tells which mods he would do over again and which we would not and does his best to quantify the improvements.  I put that together with the footage from last year showing each mod and posted this 3rd video in the series last night.

Here are the videos

Celestron Tear Down Video    https://www.youtube.com/watch?v=kTJs4r5Oj58                     

Celestron Motorized Focuser Issue and Fix   https://www.youtube.com/watch?v=kTJs4r5Oj58

Celestron Mods for Improved Performance   https://www.youtube.com/watch?v=2E3pnjDp56E

Hopefully this will help other owners of SCTs.  I would appreciate feedback from others who have made similar and different modifications and, especially anyone with the motorized focuser who has had issues with it as well.

Best Regards and Merry Christmas

Curtis

 

Edited December 24, 2022 by curtisca17
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