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Rebuilding my CGE Pro

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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.


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


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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, B McCandless and 11 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!

    • eekeek77, fdboucher and rojavastars like 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.

    • fdboucher likes this

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

    • Dale Penkala likes this

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

    • Dale Penkala and MensaDei like 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. 

    • Joe Bergeron, Iisraelmv1, lwbehney and 4 others 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

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 ;-)

Old Speckled Hen
Dec 18 2022 06:01 AM

I've always liked ther look of the CGE and that someone has offered a way back for them is "interesting" indeed.

Thanks for the heads up, just gotta find a broken one in the UK!

    • CharLakeAstro likes this
Dale Penkala
Jan 03 2023 09:17 AM

I’m glad you got your Pro back working again! I aquired one abut 3 years ago now and at the time I bought it I thought it was working well. Eventually after about 3-4 months it was doing erratic things and the Dec motor was causing tracking issues. In the end worked with a couple of guys from the Chicago area where we all had different skills and we worked together to rebuild 2 Pros and a CGE. While in the end we got all our mounts up and running (excellently I will add) I wish this would have been available at the time because there is a lot of leg work to do the rebuild for these mounts. I’m a retired tool and die maker so all the mechanical parts about the build was pretty straight forward, it was all the computer/electronics that I lacked the skills to do the work and in the end I relayed on the guys in Chicago for that part.

If I ever get the chance to pick up another Pro cheap that isn’t working I will definatly do this upgrade. 


Great article and thanks for sharing this with the astronomical community!

    • eekeek77 likes this

Hi Dale,


you're welcome. I have since taken some awesome pictures with the PHD2 guiding and Sky Planetarium software. 



Jan 12 2023 08:26 AM

I wish I had known you sooner.  My CGE-PRO with a C14HD quit working after 7 perfect years. The declination motor became balky and the computer would forget where it was.   A fellow in Chicago bought it to rehab.  It has been replaced by a CGE 120 which so far has been fine.  But the celestron was a lot easier to use, and always tracked perfectly with very accurate goto's.

B McCandless
Feb 12 2023 11:25 PM

This makes me so scared now that I have retired (not much money now) and placed all my hopes in what I thought would be a 50 year mount. The hardest part so-far was the 2005-2006 period...Celestron made-good on the mount and now all my troubles are with those stupid RS homing switches. For simple tracking operations, I have learned to simply fake-them-out when the machine is first starting (set-switch) -- those **** micro-switches are touchy and cheaply made.  After that, as long as I do not go near the E-W horizons, I can enjoy an evening of observing and photography, but only for short-duration, because with this mount, something always happens...like an adventure holiday (expensive) but without the postcard (no images that night). Shame on Celestron...

    • Thomas Ashcraft likes this

to McCandless: the retrofit is quite simple to do and much less expensive than any other solution. I can now easily track for up to three minutes (without guiding and with very good PA), or as long as 6 minutes (I have not tried longer exposures yet) with PhD2 guiding and the sky planetarium software. 

    • Special Ed likes this

OK, folks.  I am another *very* satisfied OnStep conversion kit user.  Chad Gray's very well made kit using Howard Dutton's OnStep literally resurrected my CGE Pro mount from the dead.


I bought my mount and scope new back in 2010 for $7500 and installed it on a pier in my newly constructed observatory.  I started having problems with it in 2017 and the problems got progressively worse over the next few years.  I'm talking jerking, jolting, inaccurate slews in RA and Dec.  I searched around on the net and here on CN for solutions, but nothing seemed to fix it--or people were giving up on trying to fix it.


The situation got to where I didn't trust the durn thing not to go flying off the pier or speed up suddenly and break my nose.  Something that big shouldn't go jumping around on its own. 


I came up with a workaround where I would turn on the tracking, loosen the clutches, and point the scope manually at the target.  If I kept the slew rate low, I could then center the target in the Telrad or finderscope and move it around in the FOV.  This worked for a couple of years but it was so awkward to move the beast around in the dark--it's got eight clutch points that you have to reach around the mount to find, loosen, and tighten--so I knew I couldn't keep doing that.  Plus, I really did not trust the thing not to go wild at any time--I'd seen it happen.


I started looking around for a heavy duty mount, which put me in a bad mood--I was going to have to spend four or five thousand dollars to replace my four thousand dollar boat anchor.  I was having trouble bringing myself to do it.


Naturally, when I saw MensaDei's article here I was interested.  Between what he said and a couple of others who had posted videos on YouTube, I came to believe I had found the solution--and the price was right!


Never having taken a mount apart before I was a little apprehensive, but Chad has several helpful videos on his website plus written instructions--plus the other videos by people who had already installed the kit.  And when I had a question about something, Chad was good about promptly responding via email.  Installing the conversion kit turned out to be a relatively simple task.


Learning to navigate around the menu on the hand controller was relatively easy, too--and Chad has more videos to help with that.  I've now used the system 4 times--twice on solar (so I could do things in daylight) and twice at night.  I've got a 3 star alignment in the system and putting the scope in the park position saves it for next time (like the hibernate mode in the old system).


I don't do much AP so I can't speak to that.  But the other night after the alignment, the GOTO took the scope to the target I selected and the tracking stayed on the money.  I had the scope on C/2022 E3 (ZTF) for an hour while I did an observation and sketch and the starfield remained steady, even as the comet moved through the field.


So, for $600 and some sweat equity, I have a new mount that can carry my C14 with ease and goes where I want it to go--and the installed motor boxes, hand controller, and computer look finished and professional.  I highly recommend this OnStep conversion kit.  smile.gif

    • Thomas Ashcraft, leesmojver and MensaDei like this
I’ve converted two CGE PRO mounts thanks to Chad Gray.

I’ve also separately converted a CI-700 to OnStep, and currently doing the same with a Vixen GP and SP.

OnStep is awesome, and one of the best things to come out for astronomers. No more dealing with companies who abandon their products.
Jun 01 2023 10:00 AM

Great post!

Interesting article indeed.

I have the older CGE. I purchased this mount in 2015, it was still new in the box. The original owner never used it.

It has been and still is a good mount for my C11.

Recently I was talking to Celestron’s Tech Support about my AVX and my ASIAIR Plus. He thinks that the newer hand controller of the AVX will work with the CGE and just might work with the ASI AIR. 
I just might give this a try. Failure is always an option.

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