CGEM Astrophotography- The Next Phase

The next phase for me with my Celestron CGEM is to begin using it for astrophotography. I have done some webcam imaging of Jupiter with marginal results (not due to the CGEM, but other factors such as seeing conditions), but much of my interest is in imaging deep space objects such as nebula, star clusters, and galaxies. To start with, I will perform DSLR astrophotography with the Orion ED80. To get started though, I had to make an investment in some new gear!

Below is a photo of my astrophotography setup for the CGEM. There are four types of adapters involved. Most of them are ADM adapters for mounting the ED80 to the CGEM and the autoguider scope to the ED80 (piggybacked). The others came with the autoguider (guide scope rings and mounting bar). The DSLR is a Canon XSi. More detail on my astrophotography setup below.

CGEM Astrophotography Setup- Click to Enlarge


CGEM Adapters

I decided to mount the ED80 directly to the CGEM saddle plate. I had the ADM dovetail rings and adapter set already (previously used to piggyback the ED80 to the LX200 SCT) so it was a matter of purchasing the DMM7 from ADM. This allows me to mount the ED80 to the CGEM saddle plate.


Orion Awesome Autoguider PackageAnother important component is a suitable autoguiding system. I’ve been hearing a lot about the Orion Awesome Autoguider Package so I made the purchase. It’s composed of a ShortTube 80mm refractor and StarShoot Autoguiding camera (for a very reasonable price I might add).

I needed a way to mount the autoguider to my ED80 dovetail rings so ADM set me up with two V-Series clamps that mount to each ring. This will allow the autoguider’s mounting bar to attach to the top of the ED80 dovetail rings. Thus, the Awesome Autoguider will be piggybacked to the ED80. It will be a nice light optical system for my CGEM.

Astrophotography Camera for the CGEM

I decided to upgrade from my Canon 300D and into the Canon 450D (XSi). I have been seeing some excellent astro-images with this camera (combined with the CGEM in many cases) so I’m going to give it a try! It is a 12.2 Megapixel CMOS sensor DSLR. A nice feature is the live preview mode which may help with focusing.

Bahtinov Focusing Mask

I’m also hearing a lot about Bahtinov focusing masks. Some imagers are making these masks themselves but a professionally made one is very reasonable. In fact, it was only $14.95 for the Bahtinov mask for my ED80 at These masks allow fast and easy critical focus. It’s simply a matter of adjusting focus until a symmetrical diffraction spike pattern is obtained.

The Wait

Now I’m just waiting for my equipment to arrive and for some suitable weather! I haven’t been able to use my CGEM too much lately because of the bad weather. Hopefully we will get a break soon so I can get more experience with this awesome mount and start producing astro-images. I will continue to post my progress here on AstroPhotography Tonight so please keep checking back for updates!


  1. Ray,

    Just received the Adam Block dvd from you. Adam does excellent job of walking you through the post processing steps of Adobe Photoshop for astrophotography. I have quite a few hours of training to explore now. The weather lately hasn’t been good so it will be time well spent. Good luck with your new gear, keep the articles coming.

    I am in final 24 hrs of wait before my new Celstron Edge800HD OTA arrives. The clock does not look like it is moving. Hopefully, the weather breaks soon!


    J Turner

  2. Jeff,

    Adam’s DVD should help tremendously when it comes to processing images in Photoshop.

    I received the Canon Xsi today. I am looking forward to using it for astrophotography. I think it will be a nice improvement over my 300D. My Awesome Autoguider is supposed to deliver on Monday.

    I can’t wait to hear how you Edge800HD works out for you. Keep us posted.


    Ray Shore

  3. Hi Ray,

    was wondering if you are also going to use your Celestron for deepsky astrophotography?

  4. Mike Wolski

    Hi Jeff. I am enjoying reading your cgem review. I cant wait to see your photos with the edge 8 hd. I recently got the cgem but I am waiting for the edge 8 hd. Iam also considering a short focal length refractor for wide field imaging. My cgem looks great but with no ota I have not used it yet. I am upgrading from a cg5. I am encouraged by the photos i see taken with this mount.I cant wait to start taking my own astrophotos. I also heard that imaging at long focal lengths is very difficult. I hope the cgem is up to the task because i definitly cannot afford anything else.
    Good luck and clear skies for everyone in this forum.
    Talk to you guys soon,
    Mike Wolski
    Long Island N.Y.

  5. Ray Shore

    Hi Mike,

    I used to have a CG5 with 8″ SCT. I did a lot of planetary astrophotography with that scope. I can tell you the CGEM is a nice upgrade from that mount. Much more beefy and is very capable of turning out great photos.

    You are correct on the focal length thing. It is easier to start with a short focal length scope. Everything has to be much more precise at longer focal lengths.

    Good luck with your CGEM and your Edge HD. I think you’ll like this setup!

    Ray Shore

  6. Mike Wolski

    Hi Ray, thanks for your reply. I have finally got my edge hd ota and it looks real nice. my first photo was of the ring nebula and it came out great. it is a stack of 15 30sec exposures. I used Deepskystacker and it worked great. I want to upgrade fron my olympus e-volt e-300 to the new digilal rebel. The longest exposure I can do with the e300 is 30 sec. I also need a dew heater system. (had some nights cut short latley) I also need an autoguider to help with the longer exposures with the much needed new camera. (there are alyays so many things to buy) I am encourged by the low price of the orion autoguider package. I think your website is great and i look foward to seeing some edge hd photos!

    1. AstroPhotography Tonight

      Hi Mike,
      Congrat’s on getting your Edge HD and first image from it! There never seems to be an end to the gadgets you want to buy for this pasttime. I highly encourage you to get an autoguider though. This will make a huge difference in what you can achieve. I’ve used the heck out of my Orion autoguider lately with the great weather that we’ve had. Here is a shot of the Andromeda Galaxy that I’ve been working on: I was taking 15 min. exposures of it the other night and the autoguider worked flawlessly. This photo was taken with my ED80 scope on the CGEM.
      Keep in touch. Would like to see some of your photos.
      Thanks, Ray Shore

  7. Stephman

    I have a like new CGEM on the way.
    For now, I’m going to be using a cheap, old Meade DS-114 OTA that I’ve had for years.
    It’s 114mm (4.5″ – 5″) round I believe.

    I need to connect the DS-114 to the CGEM mount head. My question for you, which saddle for CGEM do I need to get? Which saddle are you using with your CGEM mount?
    The DS-114 has a ring set around it with each ring having threaded holes on each side which I’m assuming a can use to screw the ring with OTA into the saddle I’ll need. I can provide pics if need me of the ring and OTA.

    I figured I’d ask you as you’ve written a wonderful review about your CGEM, seem very knowledgable and I’m getting myself a little confused in finding the correct CGEM saddle I’ll need for my setup.

    I’m not sure if you could chime in on this as well, down the road I’d like to pick up a used refractor, 80mm or up and mount this side by side with the old DS-114. And use this setup with my Panasonic GH-1 m4/3 dslr for some astrophotography.

    Thanks for any info you can provide, and thanks for a great review and site!


    1. AstroPhotography Tonight

      Hi Stephman,
      Congratulations on getting a CGEM! I am using the DMM7 from ADM: It looks like there are a couple of holes that might work for bolting your DS-114 rings to. The DMM12 might work as well. I would contact Anthony Divoli at ADM to be sure:

      Regarding a side-by-side setup, I have not tried this yet. But check out my friend Jeff Turner’s site: He has the CGEM with a side-by-side setup. He would be very happy to provide input on this.

      I hope this helps!

      Ray Shore

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