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CGX needs repair...or buy new? Recommendations appreciated

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#1 hamers

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Posted 08 March 2021 - 10:18 AM

I had a really bad cable snag last night while slewing and although it seemed OK last night (but made funny noise at one point) this morning when I'm trying to do some solar imaging it's shaking and I can hear a "tic....tic....tic" coming from the mount about once per second.   So the question is,  is it worth repairing a 4-year-old CGX ?  I have about $15k invested in my Tak refractor, cameras, and etalon, so if I go new I'd like something high quality.  My OTA+ accessories weights in at 31 pounds, and I'm likely want to add a second etalon.  So, let's say about 35 pounds net OTA+accessories.    

 

I do a combination of back-yard imaging and taking my rig to other locations by packing it into the hatch of my car.  I've lugged the CGX and tripod  around many places but would like to have something no heavier than that.  I do almost entirely astrophotography.

 

I'd appreciate any recommendations on (1) getting the CGX repaired,  and (2) new mounts from any manufacturerr. 

 

Thanks--


Edited by hamers, 08 March 2021 - 10:45 AM.


#2 rgsalinger

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Posted 08 March 2021 - 10:29 AM

I would give Celestron a call and see what a repair would cost and how long it would take before doing anything else. A new mount is a new adventure and if you like what you have, give them a chance to put it right. 

Rgrds-Ross


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#3 hamers

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Posted 08 March 2021 - 10:37 AM

I would give Celestron a call and see what a repair would cost and how long it would take before doing anything else. A new mount is a new adventure and if you like what you have, give them a chance to put it right. 

Rgrds-Ross

Thanks..   It's the only "good" quality equatorial mount I've ever had, so I don't have a lot to compare to.  Overall I'd say it's OK, but the tracking has never been as good as I'd like...



#4 Sandy Swede

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Posted 08 March 2021 - 10:53 AM

x2 what Ross said.

 

If you decide to replace the mount, I suggest you look at the Losmandy GM811G which is higher quality than what you currently have.  The GM811G has an imaging weight carrying capacity rated at 50 lbs.  It is pricey, but you will never regret getting it.  I love mine.  That being said, learning the intricacies of the Gemini 2 controller will take some time.  Good luck on your decision.

 

EDIT to include add'l info on the Losmandy GM811G:

The mount head in standard configuration weighs 27 lbs.  However, if you purchase the RA axis extension ($295) you get two benefits: The "RA Extension Kit is used to allow a Meridian Flip Through. This is done by adding an 1.5" to the RA body and also raising the Saddle Plate by 0.6" . With this kit the motors will not interfere when doing a Meridian Flip Through. An added feature with this kit is the ability to easily remove the DEC axis. This is useful when transporting the G11 to break down the G11 into lighter more manageable pieces."  IIRC, the DEC axis weights 11 lbs and the remaining mount head weighs 18lbs.  The entire mount with the heavy-duty tripod (35 lbs) weighs 67 lbs, but this is not a concern to me because it all rides on a Scope Buggy.  Due to my bad back, I no longer lift anything over 25 lbs.  You could make your GM811G rig even lighter by using the light-weight tripod at 15 lbs.  All in, my rig cost four large.

 

Note:  The quoted text above is from the Losmandy website.


Edited by Sandy Swede, 08 March 2021 - 12:28 PM.

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#5 rgsalinger

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Posted 08 March 2021 - 10:55 AM

Well, if you want an upgrade, that's totally a different matter. The mounts that will handle a C9.25 and be lighter than what you have will be the iOptron CEM70 (22 pounds) and the Paramount MYT (34 pounds). Either of these can handle 50 pounds for imaging and 2 meters of focal length. If you don't mind heavier, there are many other choices. Those are the two lightweight candidates in today's market. Since I own an MYT, obviously I prefer it. It's really pricey (mine was bought used) and the CEM70's, while mass produced, seem to have a relatively low level of risk in terms of getting a bad one. I don't own one so it would be up to those who do to comment on that aspect. 

 

Both of these choices have factory installed through the mount cabling. Using my CEM120 (same design as the CEM70) and my Paramounts I have only once in several years with each mount had a cable snag. That was entirely my fault when I made a hasty change at midnight about a year ago. The combination of light weight and the ability of these mounts to make cabling trivial is why I think that they have an edge over older designs. 

 

My usual advice is to see if there's a local imaging group that has examples of your possible choices and talk directly to people in your area about them. Much better than getting advice over the internet, even here, because a direct dialog is vastly superior to any post based information exchange when it comes to complicated choices.

 

I'd still get the CGX repaired, even if you sell it to fund a new mount or just keep it as a backup. 

 

Rgrds-Ross


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#6 hamers

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Posted 08 March 2021 - 12:22 PM

Well, if you want an upgrade, that's totally a different matter. The mounts that will handle a C9.25 and be lighter than what you have will be the iOptron CEM70 (22 pounds) and the Paramount MYT (34 pounds). Either of these can handle 50 pounds for imaging and 2 meters of focal length. If you don't mind heavier, there are many other choices. Those are the two lightweight candidates in today's market. Since I own an MYT, obviously I prefer it. It's really pricey (mine was bought used) and the CEM70's, while mass produced, seem to have a relatively low level of risk in terms of getting a bad one. I don't own one so it would be up to those who do to comment on that aspect. 

 

Both of these choices have factory installed through the mount cabling. Using my CEM120 (same design as the CEM70) and my Paramounts I have only once in several years with each mount had a cable snag. That was entirely my fault when I made a hasty change at midnight about a year ago. The combination of light weight and the ability of these mounts to make cabling trivial is why I think that they have an edge over older designs. 

 

My usual advice is to see if there's a local imaging group that has examples of your possible choices and talk directly to people in your area about them. Much better than getting advice over the internet, even here, because a direct dialog is vastly superior to any post based information exchange when it comes to complicated choices.

 

I'd still get the CGX repaired, even if you sell it to fund a new mount or just keep it as a backup. 

 

Rgrds-Ross

Hi- Yes, thanks for your thoughts. I am active in our local astronomical group, although there are only about 5 of us who do astrophotography, and have put out a post there too. 

best,

bob



#7 Ray Hansen

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Posted 08 March 2021 - 02:44 PM

Before you get the toolbox out, you might try flashing the HC. You would be surprised what can be fixed

with a software update. Go to software.celestron.com and get the latest CFM.


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#8 hamers

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Posted 08 March 2021 - 02:54 PM

Before you get the toolbox out, you might try flashing the HC. You would be surprised what can be fixed

with a software update. Go to software.celestron.com and get the latest CFM.

hi-

yes, good idea. I've done it before, pretty straightforward.  I'll report back tonight !

thanks for the suggestion-



#9 Jim W. S.

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Posted 21 March 2021 - 08:45 AM

I had a really bad cable snag last night while slewing and although it seemed OK last night (but made funny noise at one point) this morning when I'm trying to do some solar imaging it's shaking and I can hear a "tic....tic....tic" coming from the mount about once per second.   So the question is,  is it worth repairing a 4-year-old CGX ?  I have about $15k invested in my Tak refractor, cameras, and etalon, so if I go new I'd like something high quality.  My OTA+ accessories weights in at 31 pounds, and I'm likely want to add a second etalon.  So, let's say about 35 pounds net OTA+accessories.    

 

I do a combination of back-yard imaging and taking my rig to other locations by packing it into the hatch of my car.  I've lugged the CGX and tripod  around many places but would like to have something no heavier than that.  I do almost entirely astrophotography.

 

I'd appreciate any recommendations on (1) getting the CGX repaired,  and (2) new mounts from any manufacturerr. 

 

Thanks--

You can look at this post for tips about adjustments to RA:

 

https://www.cloudyni...n/#entry7933440



#10 mich_al

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Posted 21 March 2021 - 01:48 PM

OP, you say 'four year old mount' like that's ancient history.  Mine is 12 years old and I consider that somewhat current.  I grow weary of thinking that says anything without 'new car smell' must be replaced.


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#11 Geo.

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Posted 21 March 2021 - 01:59 PM

I think the CGEX has Pittman motors they have pretty good gearheads and were made in Penn. They've been taken over by a German firm and the Pittman line is no more. But there are a lot of used gear heads around if they're damaged. But due the cycle you are hearing it sounds like some thing slower. Maybe the Dec worm drive gears. I guess it really is how long do you want to do without it. Could be months. 

 

In that event I'd be tempted to sell it with full disclosure to someone who will under take repairs for the savings over a new mount. But remember, as I recently told my daughter, "Now you see how quickly a little inattentiveness can make a $3000 auto into a $340 junk yard queen."

 

I'd go for a Losmandy G11. They've been making them in Hollywood for 30 years. Pretty much everything machined from billet. Support at a finger tip, Good residual value. Excellent performance and a certain new loyalty to the amateur astro community that helped keep the lights on during the slowdown in studio work. Oh, and they don't take month off for Lunar New Year.



#12 aa6ww

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Posted 22 March 2021 - 10:40 AM

  Id not recommend the Losmandy with Gemini II system unless you are pretty good at figuring out how new software works. 

I've know 3 people now who have had the Gemini II system, 2 of them never got them to work properly but one figured it out and enjoyed it. He is a software developer, which might account for why he figured it out.

  I've had a dumb G11 for the last 20 years, the non GoTo mount, and its an excellent mount and very well made. 

Two years ago due to light polution, I bought 2 GoTo mounts, the AVX and CGEMII. Both are extremely easy to use and work flawlessly. I cant imagine anyone making a simpler fully functional GoTo system then Celestron. 

  If you are willing to take a stab at learning how the Gemini II systems work, by all means go for it. I don't think I'd have any problems with the Gemini II systems but don't need it.

Technically Savvy people wont have an issue with the Gemini II System, just be aware that it isn't a simple walk in the park like your CGX is.

I would recommend getting the CGX repaired not just to save money, but because its an excellent mount and you are very familiar with it already. 

 

...Ralph

 

 

x2 what Ross said.

 

If you decide to replace the mount, I suggest you look at the Losmandy GM811G which is higher quality than what you currently have.  The GM811G has an imaging weight carrying capacity rated at 50 lbs.  It is pricey, but you will never regret getting it.  I love mine.  That being said, learning the intricacies of the Gemini 2 controller will take some time.  Good luck on your decision.

 

EDIT to include add'l info on the Losmandy GM811G:

The mount head in standard configuration weighs 27 lbs.  However, if you purchase the RA axis extension ($295) you get two benefits: The "RA Extension Kit is used to allow a Meridian Flip Through. This is done by adding an 1.5" to the RA body and also raising the Saddle Plate by 0.6" . With this kit the motors will not interfere when doing a Meridian Flip Through. An added feature with this kit is the ability to easily remove the DEC axis. This is useful when transporting the G11 to break down the G11 into lighter more manageable pieces."  IIRC, the DEC axis weights 11 lbs and the remaining mount head weighs 18lbs.  The entire mount with the heavy-duty tripod (35 lbs) weighs 67 lbs, but this is not a concern to me because it all rides on a Scope Buggy.  Due to my bad back, I no longer lift anything over 25 lbs.  You could make your GM811G rig even lighter by using the light-weight tripod at 15 lbs.  All in, my rig cost four large.

 

Note:  The quoted text above is from the Losmandy website.


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#13 hamers

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Posted 22 March 2021 - 11:55 PM

  Id not recommend the Losmandy with Gemini II system unless you are pretty good at figuring out how new software works. 

I've know 3 people now who have had the Gemini II system, 2 of them never got them to work properly but one figured it out and enjoyed it. He is a software developer, which might account for why he figured it out.

  I've had a dumb G11 for the last 20 years, the non GoTo mount, and its an excellent mount and very well made. 

Two years ago due to light polution, I bought 2 GoTo mounts, the AVX and CGEMII. Both are extremely easy to use and work flawlessly. I cant imagine anyone making a simpler fully functional GoTo system then Celestron. 

  If you are willing to take a stab at learning how the Gemini II systems work, by all means go for it. I don't think I'd have any problems with the Gemini II systems but don't need it.

Technically Savvy people wont have an issue with the Gemini II System, just be aware that it isn't a simple walk in the park like your CGX is.

I would recommend getting the CGX repaired not just to save money, but because its an excellent mount and you are very familiar with it already. 

 

...Ralph

thanks for the info.   I did manage to get the CGX alive again, although the "goto" seems to be way off. I flashed the drive head and the handset and it seems to track OK, but will occasionally think a star is far away from it true coordinates. I think I'll try to order a new handset and see if that helps..   In any case, thanks for the information !



#14 aa6ww

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Posted 23 March 2021 - 11:27 AM

On the CGX, Id also check your location coordinates, time and date. A friend with a CGEM use to have random accuracy issues, and it was always his location information. Once he bought a GPS Unit, all that went away and accuracy was dead on.

I've never  used my mounts without the GPS Unit and Starsense so its always been very accurate. The GPS Unit sometimes takes a minute or so to lock onto the satellites. The GPS unit responds much faster when its mounted on top of a telescope, instead of under it.

 

...Ralph


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#15 Geo.

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Posted 23 March 2021 - 12:50 PM

  Id not recommend the Losmandy with Gemini II system unless you are pretty good at figuring out how new software works. 

I've know 3 people now who have had the Gemini II system, 2 of them never got them to work properly but one figured it out and enjoyed it. He is a software developer, which might account for why he figured it out.

  

That's why I buy used G11s with the 492 system and convert them to OnStep. Well, that and I'm cheap.


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#16 dswtan

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Posted 23 March 2021 - 04:04 PM

BTW, I am in a similar position to the OP with a couple of underperforming CGXs (and not dissimilar equipment) due to modest wear-and-tear and the occasional crash. The Hypertune service from DSP may be an option for you instead of Celestron repair, for at least peace of mind and modest upgrade (bearings, etc.). This is my current "economic" choice, since I don't want to stretch to a premium mount for multiple reasons (financial and other).

 

https://www.deepspac...stron-cgx-mount

 

That said, if I had a nice Tak, I think I might go for the whole mount upgrade if you have the financial option and location to do so. The CGX is what it is. :-) 

 

I do know Gemini 2 from my Losmandy GM8 and I don't personally get on with it even though I am quite technical. I respect the mount's mechanical qualities, but I am not a tinkerer which this mount seems to more appeal to. 


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#17 mich_al

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Posted 23 March 2021 - 07:40 PM

thanks for the info.   I did manage to get the CGX alive again, although the "goto" seems to be way off. I flashed the drive head and the handset and it seems to track OK, but will occasionally think a star is far away from it true coordinates. I think I'll try to order a new handset and see if that helps..   In any case, thanks for the information !

The 'goto' algorithm itself is rock solid and I seriously doubt and firmware update have changed it one bit so that's likely not the problem.  Goto issues are (> 99% of the time) caused by poor alignment procedures.  Not enough stars, bad centering stars (for many reasons), wrong star, poor choice of stars,  bad location / date / time, etc, etc.  The other 1% are mount issues and 0% are firmware issues.  Get the alignment process down pat and the mount will perform.



#18 hamers

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Posted 23 March 2021 - 09:24 PM

The 'goto' algorithm itself is rock solid and I seriously doubt and firmware update have changed it one bit so that's likely not the problem.  Goto issues are (> 99% of the time) caused by poor alignment procedures.  Not enough stars, bad centering stars (for many reasons), wrong star, poor choice of stars,  bad location / date / time, etc, etc.  The other 1% are mount issues and 0% are firmware issues.  Get the alignment process down pat and the mount will perform.

Hi.  Celestron acknowledges that there are some problems with the  firmware.  See  https://www.celestro...ine-why-is-this.  I don't know how "rare" this is but it's common enough that Celestron posts it on their web pages.   This database corruption has happened to me on multiple occasions where suddenly during an alignment it will careen totally off and instead of point to a star it will point somewhere in the total opposite direction,  sometimes even down well below the horizon. In the past I've found that doing a factory reset and re-download the firmware will fix it.  But it's annoying when it happens at my "dark sky" site where there's not internet connection.  Most of the time the mount works fine, but the corruption issue is annoying. 



#19 hamers

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Posted 23 March 2021 - 09:33 PM

BTW, I am in a similar position to the OP with a couple of underperforming CGXs (and not dissimilar equipment) due to modest wear-and-tear and the occasional crash. The Hypertune service from DSP may be an option for you instead of Celestron repair, for at least peace of mind and modest upgrade (bearings, etc.). This is my current "economic" choice, since I don't want to stretch to a premium mount for multiple reasons (financial and other).

 

https://www.deepspac...stron-cgx-mount

 

That said, if I had a nice Tak, I think I might go for the whole mount upgrade if you have the financial option and location to do so. The CGX is what it is. :-) 

 

I do know Gemini 2 from my Losmandy GM8 and I don't personally get on with it even though I am quite technical. I respect the mount's mechanical qualities, but I am not a tinkerer which this mount seems to more appeal to. 

T

 

Hi.  Celestron acknowledges that there are some problems with the  firmware.  See  https://www.celestro...ine-why-is-this.  I don't know how "rare" this is but it's common enough that Celestron posts it on their web pages.   This database corruption has happened to me on multiple occasions where suddenly during an alignment it will careen totally off and instead of point to a star it will point somewhere in the total opposite direction,  sometimes even down well below the horizon. In the past I've found that doing a factory reset and re-download the firmware will fix it.  But it's annoying when it happens at my "dark sky" site where there's not internet connection.  Most of the time the mount works fine, but the corruption issue is annoying. 

Thanks-- I was actually thinking about getting it hypertuned before the recent cabling incident.   I think I'm almost certain to go ahead with that.    I have some damaged cabling as well, so perhaps when they're doing the hyper-tuning they can also replace the cables.  


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#20 Jeffmar

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Posted 23 March 2021 - 10:03 PM

OP, you say 'four year old mount' like that's ancient history.  Mine is 12 years old and I consider that somewhat current.  I grow weary of thinking that says anything without 'new car smell' must be replaced.

I have a big Yamaha motorcyle that was made in 1992 that still runs great and I have never had to do a major repair on it. Unfortunately my CGX, now 5 years old, stopped working last summer. There just might be a difference in the build quality between these two machines.


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#21 Sacred Heart

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Posted 24 March 2021 - 11:02 AM

Is your problem in RA or Dec.   Take that cover off and see what is going on.  Is it the belt, worm, or a spur gear??   Joe



#22 Jeff_Richards

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Posted 24 March 2021 - 11:57 AM

T

 

Thanks-- I was actually thinking about getting it hypertuned before the recent cabling incident.   I think I'm almost certain to go ahead with that.    I have some damaged cabling as well, so perhaps when they're doing the hyper-tuning they can also replace the cables.  

The hypertune is a very good option. You mention damaged cables and the Hypertune process replacing them. Are you talking damaged internal mount cables? If so, that very well could explain your recent performance issues. Although if there was some sort of intermittent internal connection I would expect a "no response 16 or 17" type of error to show up on your hand controller.


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#23 hamers

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Posted 24 March 2021 - 09:29 PM

The hypertune is a very good option. You mention damaged cables and the Hypertune process replacing them. Are you talking damaged internal mount cables? If so, that very well could explain your recent performance issues. Although if there was some sort of intermittent internal connection I would expect a "no response 16 or 17" type of error to show up on your hand controller.

I had an error about a declination switch error and so opened up the mount and found that one of the cables had become tangled in the mount RA axis and abraded away some of the  plastic insulation and eventually pulled the declination cable connector out of the circuit board that is directly underneath the power switch (bottom photo).. You can see the gray outer cable is worn through, and some of the fiberglass insulation is on the inside of the housing. It's  a multi-conductor cable  that seems to carry  two unshielded twisted-pari wires for the RA and DEC switches.  Only the outer, grayish plastic part was damaged; no damage to the actual wire insulation of the two pairs of wires.  But there are some "fins" on the inside of the RA housing that seem to be intended to keep the cables away from the RA bearing, and one of those fins seems to be broken, so that concerns me along with the fiberglass "dust" that is inside and will therefore get into the main RA bearing. 

IMG_5524.jpg

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  • IMG_5523.jpg

Edited by hamers, 24 March 2021 - 09:39 PM.

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