Jump to content


* * * * *

Rebuilding my CGE Pro

Discuss this article in our forums

Rebuilding my CGE Pro

by Benne Piscaer (CN member MensaDei)


Celestron has stopped repairing and selling replacement parts for the CGE Pro for some time now. This former heavy equatorial mount had a payload of approx. 45 kg, more than enough to carry their heaviest telescope. The mount was solidly built and reliable.

My CGE Pro started having pointing and tracking problems after installing the Celestron WLAN SkyPortal module and became completely useless.  I found a “clone” of the MC online from Camera Concept in NY and after installation, all seemed to work fine. But as soon as I used the Skyportal module again, the same problems came again: Declination didn't respond correctly and the mount was completely messed up, even a simple polar alignment became impossible.

I loved my CGE Pro, and I had no intention of buying a new CGX-L with tripod or using my CGE Pro as a flower stand or doorstop.

Thus, I started looking online for those who had similar experiences and maybe solutions. Solutions with replacing components with expensive reproductions could lead to the same issues again. And there were no longer HC or MC updates. I found some parts (such as servomotors) could be bought via Cloudy Nights and Camera Concept, but origin and delivery time are often unknown. Moreover the costs to replace the different parts was relatively high.

My search online lead to a website owned by an amateur and long-time Celestron CGE Pro owner, Chad Gray, who had faced the same issues with his CGE Pro. Turns out he did a retrofit of his mount with stepper motors instead of servos and a controller based on the OnStep computer (with Sky Planetarium). Chad is making these sets available to CGE Pro owners who want to give a second life to the mount. He has clearly illustrated the mounting and operation in a series of videos that you can find here.

The package offered consists of two parts: the stepper motors with belt connection, and the computer with cables. Everything fits neatly in 3D printed boxes that replace the original motor cases (the computer is mounted on the side of the electronics pier). Wi-Fi is included.

Instructions are included and very clear, supplemented with YouTube Videos (CGE Pro Onstep Conversion Chad Gray) illustrating everything clearly. The cost of the package is less than the cost of a servo motor clone from Mexico!!


Below are a few pictures of the completed Onstep module and the RA motor cabinet with the stepper motor.


size reduced to fit the page - click on the picture above for a full size version in a separate tab


size reduced to fit the page - click on the pictures above for a full size version in a separate tab


size reduced to fit the page - click on the pictures above for a full size version in a separate tab


size reduced to fit the page - click on the pictures above for a full size version in a separate tab


some views of the motor assemblies


The OnStep software is simple and logical, and in combination with Sky Planetarium software my old CGE Pro has many extras. There is also an ease of use comparable to Celestron's Nexstar.


After the installation, a few more adjustments were needed, which were solved swiftly with Chad. And I got fast answers and assistance. So I just waited for a clear night and “first light” with the retrofitted CGE Pro.


The setup: a Tec 102mm F7 apo with AISAir Plus and the ASI


Visually the result is beautiful, astrophotography requires tracking (tracking alone produces round stars up to about 90 sec.). I did a “3 star alignment” and I think, with the “9 star alignment” a better model and better tracking is possible, without the need for autoguiding.


A first result was M13 (taken without filter):


size reduced to fit the page - click on the picture above for a full size version in a separate tab




  • LarryAlvarez, Thomas Ashcraft, okiestarman56 and 6 others like this


Interesting article.  I've got a 10 year old CGEM-DX that I hyper-tuned after a lot of issues with tracking.  It's been performing well since the Hypertune but, I'm wondering how long until one of the motors or the controller board go offline permanently.  With everything running well for now, I'll continuing to use the mount until the very end.  In the meantime I"m considering which mount may replace it.  After reading articles like this one, I'm not confident that I would purchase another Celestron mount at this point. 


There are many equatorial mounts, although there are precious few that can handle a a 25 kg payload.  No clear choices.  One thing I will say is that after all the good times I've had surfing the heavens with this mount I've got a sentimental attachment to it.  Replacing it with another mount won't necessarily get me better performance, but like all machines, there is a lifecycle that is limited mostly by the availability of spare parts.  Hopefully, I won't have to get another mount in the near term.


Thanks again for the article.  Good news to hear that you've resurrected your CGE Pro. Hope it lasts many years going forward.  Cheers & Clear Skies!

    • rojavastars likes this

Hi Dupree, thanks for the comment. As you can read I didn't want to part from a great mount with a 45kg payload. So while I have an EQ8 Pro, the CGE Pro is now mounted on a three wheel adjustable dolly, allowing me to avoid the limits of my observatory (limited horizon view) and enjoying a certain mobility. And it was a very satisfying project with a great outcome. Since clear skies have been very rare since I finished the rebuilt, I hope to show some deep sky pictures soon. In essence, I just do not want to let go things to waste.

And you shouldn't. That mount cost you good money and i am glad you returned it to life

Onstep rocks. ATMers owe a debt of gratitude to Howard Dutton for developing the original software and hardware as a freeware.

    • MensaDei likes this
Oct 25 2022 09:40 PM

Sorry I sold my mount but the retrofit was not available (I think) three years ago when my mount died.

Nov 03 2022 10:02 PM

My CGE Pro quit working two weeks after I bought it new. I returned it to factory and received it back working with no cost to me. It ran for another two years and totally quit working again. With no replacement parts I gave up on it and replaced it with a Losmandy G-11 T. This is a great mount and Losmandy has great service and replacement parts, of witch I have not had to use for the mount is working very well. If you want a mount you can depend on please check Losmandy out for peace of mind and value for your money. These mounts are made in the USA and are competitive with the Chinese build mounts with much better quality. Sounds impossible but do yourself a favor and research the Losmandy mounts. 

    • lwbehney, bryanj2990 and MensaDei like this

I had finally a clear sky, after months of cloudy or rainy nights. I made a few 300sec 1 bin pictures with the TS 102 F7 refractor.http://C:\Users\benn...ht_Stack_22.jpg

Bob Berta
Today, 02:06 PM

I manage a Scout observatory that has the CGE PRO and a 14" SCT HD. Thus far it all works fine but who knows when something goes wrong. My own personal mounts include an AP 1100 and a AP 900 neither of which have given any grief and of course run superbly. While these are more expensive by far than the Chinese mounts....in the long run I am happy that they don't have planned obsolescence built in.


I had an old Vixen SS 2K Setup but there are no replacement parts available (I need the wiring harness) so it is now a door stop. That was a REALLY excellent setup. That was Japanese so the Chinese electronics aren't alone in lack of support. I even contacted the company in Japan but no luck ;-)

Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics