Celestron CGEM EQ Mount

[John]

I've been offered a used Celestron CGEM as a possible mount for my 6" F/12 refractor, for visual use only. The CGEM in question is the standard version, rather than the DX.

I don't know much about these - can anyone summarise their pros & cons for me please ?

I guess the main question in my mind is whether an EQ6 might be a better bet even though it's capacity is a bit less than the published limits for the CGEM ?

I have read about issues with early versions of the CGEM's but it's hard to put my finger on whether these are still persisting issues or have been largely sorted now.

Many thanks 

PS: I know these are going to be HEAVY bits of kit. This 6" frac is going to give me a real workout 

[r3i]

The EQ6 & CGEM are essentially in the same ball-park in terms of capacity & performance.

Do you know how old it is?  There was a number of issues reported with the CGEM when it first came out a few years ago (which is why at the time was one reason I went for the EQ6) - the reports were mainly on the CN site, as the CGEM looked to be a more popular choice in the USA.  However since then, reports of dud CGEMs have all but died out so it looks like Celestron have got the gremlins sorted.

In terms of functionality,  I believe the CGEM has a more advanced handset but perhaps the latest firmware updates on the SynScan have caught up? I don't know as I use EQMOD.  Then in terms of hardware, the EQ6 uses stepper motors whereas the CGEM has servo motors.

So I guess it depends on how old it is and how much the seller is asking for it.  EQ6's come up regularly on UKABS so you should be able to compare prices.

[emadmoussa]

I've seen your ad on ABS looking for a heavy duty giro? I have been looking for the same for a while now, very rare to come up unfortunately.

I don't know about the CGEM, but if you want to take the path of the EQ6 you'll probably need a better saddle considering the long focal length and weight of your Istar. And also, you REALLY need a very sturdy mount. I have my NEQ6 on pillar mount, which is sturdier on solid ground than a tripod, but I still get vibration with the 6" frac which weighs about 11Kg and I use it mainly for visual.

[Naemeth]

Isn't the CGEM-DX just the regular CGEM with the CGE Pro Tripod?

[John]

Interesting feedback so far folks - thanks very much 

I've seen your ad on ABS looking for a heavy duty giro? I have been looking for the same for a while now, very rare to come up unfortunately.

I don't know about the CGEM, but if you want to take the path of the EQ6 you'll probably need a better saddle considering the long focal length and weight of your Istar. And also, you REALLY need a very sturdy mount. I have my NEQ6 on pillar mount, which is sturdier on solid ground than a tripod, but I still get vibration with the 6" frac which weighs about 11Kg and I use it mainly for visual.

Thanks for the tips re: the EQ6 saddle and the pillar.

I agree that these extra HD Giro-type mounts are thin on the ground to say the least. I could buy a new APM Maxload but the cost is £800+ and then there is still the tripod / pillar to find which could add a further £300-£400. 

The CGEM I've been offered is considerably less than the above prices as are used EQ6's, plus there are lots about.

I never expect this to be an easy scope to mount though 

[emadmoussa]

Having seen your posts and mods, it's obvious you've got decent DIY skills. Can't build a large fork mount?

[r3i]

Isn't the CGEM-DX just the regular CGEM with the CGE Pro Tripod?

I think it also has beefed up motors.

[John]

Having seen your posts and mods, it's obvious you've got decent DIY skills. Can't build a large fork mount?

Thats another possibility I'm considering. I'm OK with woodworking, up to a point, but I don't have any metal working facilities. There are all wood designs out there though so they could have potential. 

In case you are thinking about my dob mount, Shane (Moonshane) made that and its quality of construction and finish is beyond my ability I reckon

There are some small engineering firms that I'm aware of that do this sort of thing as well.

Although I am a big fan of the alt-azimuth approach, I'm aware that a robust equatorial might have some advantages for this particular purpose. The drive systems should reduce the amount of times that the scope tube will need to be touched and that will help combat the shake / vibrations that these long tubes are afflicted by. 

[emadmoussa]

To be honest part the main reason I'm getting a giro is that for visual equatorial is a bit awkward. You can always get a motorized Alt-azimuth...

[emadmoussa]

One thought though, you could probably create another dob base for the refractor and raise it on a pillar. It'll require some modifications of course. The design is in my head, but don't really have the DIY skills to apply it

[Naemeth]

Thats another possibility I'm considering. I'm OK with woodworking, up to a point, but I don't have any metal working facilities. There are all wood designs out there though so they could have potential. 

In case you are thinking about my dob mount, Shane (Moonshane) made that and its quality of construction and finish is beyond my ability I reckon

There are some small engineering firms that I'm aware of that do this sort of thing as well.

Although I am a big fan of the alt-azimuth approach, I'm aware that a robust equatorial might have some advantages for this particular purpose. The drive systems should reduce the amount of times that the scope tube will need to be touched and that will help combat the shake / vibrations that these long tubes are afflicted by. 

I know you were considering a Berlebach tripod at one point - would this be the answer? The EQ6 version has a rated payload of 100kg, only the length of the OTA would be an issue then.

[John]

I know you were considering a Berlebach tripod at one point - would this be the answer? The EQ6 version has a rated payload of 100kg, only the length of the OTA would be an issue then.

Yes, an EQ6 on a Berlebach UNI 28 is a possible solution. The tripods seem never to come up used so I'd need to budget for a new one plus, say £400-£700 for a used EQ6 (non GOTO at the cheaper end). Pity Meade LX80 seems so problematical - on paper it looks an interesting contender but all the revews / feedback I've read suggest leaving it well alone 

There are quite a lot of options available but I'm just taking time to explore different avenues that are feasible without spending more than the scope cost - thats a sort of psychological "line in the sand" with this project, for me  

[Naemeth]

Yes, an EQ6 on a Berlebach UNI 28 is a possible solution. The tripods seem never to come up used so I'd need to budget for a new one plus, say £400-£700 for a used EQ6 (non GOTO at the cheaper end). Pity Meade LX80 seems so problematical - on paper it looks an interesting contender but all the revews / feedback I've read suggest leaving it well alone 

There are quite a lot of options available but I'm just taking time to explore different avenues that are feasible without spending more than the scope cost - thats a sort of psychological "line in the sand" with this project, for me  

Sometimes it's an impossible or impractical goal though. Most components of my travel kit were a significant proportion of the cost of the OTA (most were 2/3rds), I ended up paying over 4 times the price of the OTA for the whole thing .

[Laurie61]

I think I was one of the early adopters in the UK having bought my CGEM in December 09. The mount was ordered to arrive before Xmas and I took delivery around the 15th. The first one had a fault and the head was picked up and replaced, the new one worked fine until a few months ago and then developed a similar problem to the original. I have a feeling it's something daft like a loose connection and will be getting an electrical engineer friend to have a look at it in November. I have mostly used this mount with my 300mm newt when planetary imaging, when polar aligned the tracking was nice and smooth keeping

the target in the field of view for several minuets at very long focal lengths. On the few times I tried the go-to it did not seem very accurate although I have not gone through the inbuilt polar align routine or updated the firmware on this mount. The counter weight shaft is too short for the general weight capacity of the mount and the hand control cable is also to short. So my opinion of the mount is definitely mixed but others seem to have no issues and are happy.

     

[John]

Thats very interesting feedback Laurie61 and thanks for the pic as well 

I reckon your 12" F/6 (and my 12" F/5.3 for that matter) are in the same sort of ball park in terms of weight and length as the 6" F/12 refractor so it's interesting that the mount seems to be able to cope well enough for visual observing, which is what I do.

I really don't need a GOTO facility at all so just using the mount as a driven EQ will do the trick.

Thanks again for posting   

[SnakeyJ]

I would have thought an EQ6 mount, with the pier extension and Losmandy mounting hardware would be comparable with the CGEM - with the advantage of a good s/h market for parts and service in UK.     Perhaps a custom pier similar to Bizibuilder's external mount might give a better height and stability?

Though with your penchant for refractors it might be worth buying the EQ8, so you have spare capacity for the F12 8" that may lurk in the future

[John]

I would have thought an EQ6 mount, with the pier extension and Losmandy mounting hardware would be comparable with the CGEM - with the advantage of a good s/h market for parts and service in UK.     Perhaps a custom pier similar to Bizibuilder's external mount might give a better height and stability?

Though with your penchant for refractors it might be worth buying the EQ8, so you have spare capacity for the F12 8" that may lurk in the future

The EQ6 has been suggested to me more often than any other solution so there is a clear message there I reckon   

Istar do an 8" F/9 which is actually physically shorter than my 6" F/12 but about 12lbs heavier. They also do a 12" F/10 to special order

I think that last one should include the services of a divorce lawyer   

[Naemeth]

Istar do an 8" F/9 which is actually physically shorter than my 6" F/12 but about 12lbs heavier. They also do a 12" F/10 to special order

I think that last one should include the services of a divorce lawyer   

Hmm... tempting .

[SnakeyJ]

I'm off to check their website for the price on that 10" F10 - though would need to consider an extension to my obsy and overdraught

[Willarnold]

I've got a CGEM with my C11. It's a big solid beast, and handles my C11 with no problem. The CGEM is nice and accurate, and I've never had any issues with it.

Cheers

Will

[John]

Thanks for the positive CGEM feedback Will - thats good to hear 

[todd8137]

Hi not sure if am late to the thread I have this mount pier mounted as you can see I have all the latest updates motors ,tracking and handset ,I had one prob with this I could not get balance after about 18 months of perfect use , I sent it back to David hinds via the shop it was the motor that was at fault they replaced the motors and it's now brill again,I drift aligned this on my pier the goto works brill ,I image with the frac. And it's superb ,the tracking use in PhD when I image is brill the SW mounts will not track past the meridian which can cut short your image runs ( not sure if eq mod will )

Any mount will work well if you do not put to bigger scope up mounts are like cars some people love fords others love BMW they all cars

Pat