Celestron CGX-L review

[jeffmar]

The image above was taken using about 25 subframes using a Sony A7III camera, a Celestron C8 EDGHD with a .7 reducer, and a Celestron CGX-L mount.

 

Early last fall I bought a C14 and put it on my Celestron CGX mount. That telescope with a diagonal, eyepiece, and a finder scope takes it just about to the limit the CGX can carry. I had to buy an extra 17 pound weight to make it work, but for visual astronomy it did fine. When I tried some short exposure, unguided imaging, there were a few issues. There was a slight wind and there were horses in a small pasture 50 feet away. Any breeze would elongate the stars. Every time one of the horses stomped its hooves, the photo looked like every star had an identical double right next to it. I don’t think any mount will keep a telescope stable with large animals making the ground vibrate but it might help with the wind. 

I decided to drain the rest of my savings on a sturdier mount. The basic structure of the CGX and CGX-l mounts are identical with a few differences. The CGX-L has a much more substantial tripod. The worm wheels for declination and right ascension have about a 50% larger diameter. The counterweight shaft is 31mm rather than 20mm for the CGX. After using my new CGX-L for a few nights at star parties I can say it is noticeably more stable with my C14 than when I was using the smaller mount.

The best part of my CGX-L mount is how good it is with unguided tracking. I did some imaging with my C14 with a .7 focal reducer at exposure lengths between 10 seconds and 45 seconds. Most of the the  photos had round stars and were usable. When I put my C8 on the mount and did some imaging it was better.  Nearly all the subframes were usable, and I was imaging, unguided, for up to a minute. From now on I will likely use my C8 for the bulk of my imaging with the CGX-L mount, and use my C14 mostly for star parties and staring at faint fuzzies, gas giants, mars and the moon. 

I recently upgraded my guiding system and haven’t worked out the bugs yet, but I can’t wait to try out the C8/CGX-L combination with guiding. It should come as no surprise that ta C14 that has a focal length of nearly 2800 mm, with a .7 reducer, is going to be less forgiving than nearly any other scope.

Overall I am very pleased with my new mount. The CGX-L has no backlash and doesn’t seem to mind if the balance isn’t perfect. I can’t tell you how well it works with auto guiding because I haven’t tried it yet, but I am hopeful that it works well. The only downside of the mount is the CGX-L tripod is three times as heavy as the CGX tripod and the mount itself is no lightweight. lugging the three 22 pound counterweights around is a bit of a workout. It is fortunate the mount head has carry handles that make it much easier to handle than other, lighter, mounts I have owned. 

 

Edited February 29, 2020 by jeffmar

[Miguel1983]

That's some serious gear you got there !

Can you elaborate on comparing the views between the Edge and the regular SCT, i'm very happy with my C11 but i haven't got the chance looking trough an Edge HD model.

[Benjam]

I too have the Edge 8 HD and 0.7 reducer, though I’m using the AVX mount. I’m in the process of upgrading my AVX for the CGX-L mount, so I’m great full for you're review. 

Thank you 

[jeffmar]

8 hours ago, Miguel1983 said:

That's some serious gear you got there !

Can you elaborate on comparing the views between the Edge and the regular SCT, i'm very happy with my C11 but i haven't got the chance looking trough an Edge HD model.

I had a chance to compare my C11 Edge to a contemporary C11 XLT at a star party. The two scopes were right next to each other and even some of the eyepieces being used in both scopes were identical. Viewing the some objects with the same eyepieces I could not tell the difference between the two scopes. They were both very good. We looked at M13, M5, M11, M57, M20 and M27. All the eyepieces had the same apparent 70 degree field of view. I think sct’s from Celestron have been consistently good in recent years. Seeing is probably the only thing that limits these scopes.

I can’t compare the XLT model to the Edge model for astrophotography, but I do own a 30 year old C11 I have used for imaging. My newer Edge model has much better coatings and mirrors, so images are much brighter. The stars in images taken with the newer scope are round with no distortion, toward the edges. 

[jeffmar]

6 hours ago, Benjam said:

I too have the Edge 8 HD and 0.7 reducer, though I’m using the AVX mount. I’m in the process of upgrading my AVX for the CGX-L mount, so I’m great full for you're review. 

Thank you 

I am happy that I helped. My C8 on my CGX-L was very stable and tracked very well. I took some pains to get a good polar alignment, and of course that is a huge factor. At one point during my imaging session I went back into the house for dinner and to get warm for an hour. When I came back out the object, I had been imaging, was still near the center of the lcd display, on my camera. It will be fun to see what this setup can do when I get my auto guiding working.

Edited February 29, 2020 by jeffmar

[Miguel1983]

15 hours ago, jeffmar said:

I had a chance to compare my C11 Edge to a contemporary C11 XLT at a star party. The two scopes were right next to each other and even some of the eyepieces being used in both scopes were identical. Viewing the some objects with the same eyepieces I could not tell the difference between the two scopes. They were both very good. We looked at M13, M5, M11, M57, M20 and M27. All the eyepieces had the same apparent 70 degree field of view. I think sct’s from Celestron have been consistently good in recent years. Seeing is probably the only thing that limits these scopes.

I can’t compare the XLT model to the Edge model for astrophotography, but I do own a 30 year old C11 I have used for imaging. My newer Edge model has much better coatings and mirrors, so images are much brighter. The stars in images taken with the newer scope are round with no distortion, toward the edges. 

Thanks for your report, so in summary, for visual there's really no need to spend the extra cash for an Edge HD model, but for visual it is justified .

[jeffmar]

13 hours ago, Miguel1983 said:

Thanks for your report, so in summary, for visual there's really no need to spend the extra cash for an Edge HD model, but for visual it is justified .

You meant, for imaging it is justified? For visual I couldn’t tell a difference with any eyepieces I own.

A have noticed a lot of great images done with the non edge version of the C11 also. With cameras with smaller sensors there wouldn’t be distorted stars in the image anyway. 

The qualifier, I think, is the edge model is useful for imaging with full frame cameras, and perhaps for cameras with what some people call crop sensors, which is the next size down.

[Miguel1983]

7 hours ago, jeffmar said:

You meant, for imaging it is justified? For visual I couldn’t tell a difference with any eyepieces I own.

A have noticed a lot of great images done with the non edge version of the C11 also. With cameras with smaller sensors there wouldn’t be distorted stars in the image anyway. 

The qualifier, I think, is the edge model is useful for imaging with full frame cameras, and perhaps for cameras with what some people call crop sensors, which is the next size down.

Ah, yes i mistyped there, i meant for imaging.

You're probably right about the sensor size too.

For planetary imaging for example, witch i've done  with my C11, it's fine.

[StarGazingSiouxsie]

On 28/02/2020 at 23:51, jeffmar said:

The image above was taken using about 25 subframes using a Sony A7III camera, a Celestron C8 EDGHD with a .7 reducer, and a Celestron CGX-L mount.

 

Early last fall I bought a C14 and put it on my Celestron CGX mount. That telescope with a diagonal, eyepiece, and a finder scope takes it just about to the limit the CGX can carry. I had to buy an extra 17 pound weight to make it work, but for visual astronomy it did fine. When I tried some short exposure, unguided imaging, there were a few issues. There was a slight wind and there were horses in a small pasture 50 feet away. Any breeze would elongate the stars. Every time one of the horses stomped its hooves, the photo looked like every star had an identical double right next to it. I don’t think any mount will keep a telescope stable with large animals making the ground vibrate but it might help with the wind. 

I decided to drain the rest of my savings on a sturdier mount. The basic structure of the CGX and CGX-l mounts are identical with a few differences. The CGX-L has a much more substantial tripod. The worm wheels for declination and right ascension have about a 50% larger diameter. The counterweight shaft is 31mm rather than 20mm for the CGX. After using my new CGX-L for a few nights at star parties I can say it is noticeably more stable with my C14 than when I was using the smaller mount.

The best part of my CGX-L mount is how good it is with unguided tracking. I did some imaging with my C14 with a .7 focal reducer at exposure lengths between 10 seconds and 45 seconds. Most of the the  photos had round stars and were usable. When I put my C8 on the mount and did some imaging it was better.  Nearly all the subframes were usable, and I was imaging, unguided, for up to a minute. From now on I will likely use my C8 for the bulk of my imaging with the CGX-L mount, and use my C14 mostly for star parties and staring at faint fuzzies, gas giants, mars and the moon. 

I recently upgraded my guiding system and haven’t worked out the bugs yet, but I can’t wait to try out the C8/CGX-L combination with guiding. It should come as no surprise that ta C14 that has a focal length of nearly 2800 mm, with a .7 reducer, is going to be less forgiving than nearly any other scope.

Overall I am very pleased with my new mount. The CGX-L has no backlash and doesn’t seem to mind if the balance isn’t perfect. I can’t tell you how well it works with auto guiding because I haven’t tried it yet, but I am hopeful that it works well. The only downside of the mount is the CGX-L tripod is three times as heavy as the CGX tripod and the mount itself is no lightweight. lugging the three 22 pound counterweights around is a bit of a workout. It is fortunate the mount head has carry handles that make it much easier to handle than other, lighter, mounts I have owned. 

 

Hey there

I am rather late on this thread..... 

I love your picture of Orion! Like you, I sometimes use my 8" Edge on a CGXL. I also shoot unguided and can sometimes get near 2 minutes when the atmosphere alllows it. 

Regarding your image, can I ask what length you exposures were and if you used any filters? I haven't imaged Orion yet but am planning to next time it comes round and I'd love to get an image similar to yours! 

Thanks & the clearest of skies to you!

 

Siouxsie