Celestron CGEM Review- Part 2

This is the second in a series of reviews for my new CGEM mount from Orion Telescopes and Binoculars. This review covers the first night out with the CGEM. It was mostly a test of the goto functionality of the telescope.

I recived the CGEM on Monday September 14th, 2009 but didn’t get a chance to put it to the real test until the following Thursday. As mentioned in my first review of the CGEM, it was cloudy the night of receiving it. My chance came a few nights later with partly cloudy skies.

Setting up the CGEM

CGEM Review- GotoI’m not keeping the CGEM in the observatory for now. It is fully set up in my garage. To transfer it to my yard, I remove the optical tube and counterweights and set them aside. This leaves the mount on the tripod. To make it easy to get through the door and fence gate in the backyard, I shorten the legs of the tripod. I can get a firm grip on the top of the tripod legs and carry it to the backyard. I avoid grabbing the mount as to not strip out the gears. Although the mount/tripod combination is a bit heavy for me, it seems to be fairly well-balanced for carrying (without straining the back too much!).

Setting it back up in the yard was a fairly quick process. I set the tripod down and adjusted it to be roughly aimed at Polaris. I didn’t need a precise polar alignment since I was only testing the goto capability of the CGEM. Then I re-attached the counterweights and optical tube.

Two-Star Alignment

After powering up the CGEM, I started the Two-Star Alignment process. First, the index marks on the RA and DEC axis were aligned. Then, the hand controller prompted me to to select the first star.

CGEM-ArcturusArcturus in the constellation Bootes was the first on the list of named stars and I noticed that it was still visible on the western horizon. This was a nice bright familiar star to start with. So I hit enter and the telescope started slewing automatically in the direction of Arcturus. Then, the hand controller prompted me to center the star in the viewfinder. After doing this, I was instructed to center it in the eyepiece then press the align button.




This process was repeated for the second star which was Vega in the constellation Lyra. I knew that I would be coming back to this constellation later for a view of the Ring Nebula!







Then, the CGEM prompted me to add a calibration star. I must have gotten too anxious to try out the goto and I by-passed this step. Not good! The goto was not accurate at all.

CGEM-AltairI decided to start the alignment process over completely and I added the star Altair for calibration. This is where it got exciting! The first object I selected in the hand controller (to slew to) was Jupiter. To my amazement, it centered the planet almost perfectly! And I must say, Jupiter and it’s moons were an awesome site in the eyepiece!

After my first stop at Jupiter, it was time to try a Messier object. I saw that the constellation Hercules was up so I commanded the CGEM to slew to M13 (The Hercules Star Cluster). Again, the goto was spot on! I was amazed at this point how easy it was to set up the goto on the CGEM and how accurate it was. One recommendation is to have a star chart handy at the telescope. The CGEM hand controller provides a list of stars to choose from at each stage. If you have a laptop at your observing site, then there is a free program called Stellarium that is nice to use. Learn about Stellarium here on AstroPhotography Tonight.

I continued with my goto test by hopping over to the Ring Nebula then the Dumbell Nebula. Same result on the accuracy. After the second alignment, all objects were almost perfectly centered in the eyepiece. The goto test was a success! At this point, I was thoroughly thrilled with the CGEM.


  1. Hello, I like your CGEM review. Keep up the good work. I own the Celestron CG-5 and wanted to make an upgrade to either the Orion Atlas Mount or the Celestron CGEM Mount. Any thought on the differences between these two mounts? I plan on using the mount for astrophotography with my 80mm Orion ED Apo and Celestron C8 OTA. Is the All Star Alignment a huge leap for polar alignment or mainly marketing hype for the CGEM? My CG-5 is giving me tracking problems right now on basic tracking with the Orion StarShoot Autoguider. It didn’t before. Any info appreciated. Thanks.


  2. Hi, thanks. I used to own a CG-5 and although I did a lot of good work in astrophotography with it, it doesn’t compare to the CGEM. But the Orion Atlas mount does appear to be a very close competitor to the CGEM from what I’ve read. I’m still not sure on the All Star Alignment being a huge leap, but it does seem to help get the polar alignment close in a short amount of time. In my first trials, I found that I still had to follow-up with a drift alignment. I think with more practice with the All Star Alignment, it might get better.

    I chose the CGEM over the Atlas for a few reasons. One being the All Star Alignment. Also, I liked how the CGEM is supposed to track well past the meridian before it has to be flipped. I confirmed this when I was imaging Jupiter one night. It did indeed track way past the meridian. Also, I was hearing how the NexStar computer program is more sophisticated than the Atlas’ SynScan program. Finally, I liked the wide saddle plate that Celestron put on the CGEM. Looks like a very stable platform.

    I did consider the Atlas very seriously though. It’s been on the market longer than the CGEM so many of the bugs should be ironed out. It would certainly be my second choice in this class of mounts.

    I hope that helps!

    Ray Shore

  3. Can you provide an update to your review? I am planning to order a CGEM, but are undecided between the 9.25 inch and the 11 inch. I do not know how the mount will stand up to the demands of an 11 inch scope. Any suggestions or recommendations based on your experience?

  4. Jose,

    Do you plan to do astrophotography? I’m still gathering gear to start imaging with my 9.25″ CGEM so still have much to report later. Some are concerned about the CGEM supporting the 11″ OTA but there is a report of it being adequate for astrophotography here: http://www.celestronimages.com/details.php?image_id=2248.

    Sorry I don’t have much information yet! More to come.

    Ray Shore

  5. Hi, Ray:

    Thanks for your help. I read the info on the web page and I still have some doubts (BTW that Orion photo is great). The thing that worries me about the capacity of the CGEM mount relative to the 11inch OTA is whether it can maintain long-term performance. I cannot go into a CGE mount at this moment and a telescope with mount is an expense you don’t do frequently. What I would like to do is get a good OTA with a good mount and later upgrade the mount.

    As to your question, yes I am planning on doing astrophotography. That is the reason I want a good mount. All I have read about the CGEM indicates is a good and quite solid mount that can be used for astrophotography, at least for a person beginning in astrophotography. My goal is the CGE Pro but later.

    BTW, do you know if Celestron offers the tripod used with the CGE Pro as a separate item? I think that this tripod could help the CGEM when used with a heavier OTA such as the 11 inch in terms of vibration.

    If you have further ideas and suggestions they will be greatly appreciated.

  6. Hello Jose,

    I’ve read other places where they say the 11″ OTA for the CGEM is a bit too much of a load for astrophotography. Especially when you mount other equipment such as a guidescope, camera, etc. It’s a tough call on this since you want as much aperature as possible and plan to upgrade to the CGE Pro later.

    I’m not sure if Celestron offers the CGE Pro tripod as a separate item. You may be able to find it used because a lot of people will mount their scope on a permanent pier. You might check Astromart on this one.


  7. Hi Ray,

    After reading quite a lot about available scopes (tubes abd mounts) I am starting to consider stretching the budget quite a bit and consider an 11inch Celestronf EdgeHD with the CGEM mount. This could give me the advantage of both, aperture and the new aplanatic technology plus the mirror clutches of the HD series. The CGEM mount seems to be quite sturdy according to the sky and telescope reviews that are featured on Celestron’s own site (although they sound more like an infomertial).

    Now, that could mean postponing a new sturdier mount more into the future than buying the not HD 11 inch version. But I think it could give me an advantage right from the start.

    Do you know of any amateur astronomer that has already tried the Edge HD series, in particular the 11 inch one? I would like to establish contact with anyone that has this new scope in order to obtain information.

    I will keep you posted as my decision progresses. If anything goes according to plan, I shall be making a purchase before the end of March.

  8. Hi Jose,

    I don’t know anyone with the Edge HD 11″, but I do know someone who just recieved the 8″ version. His name is Jeff Turner at http://www.daltonskygazer.com. He may have some knowledge of the 11″ Edge HD from his research. I understand why the 11″ on the CGEM is tempting!


  9. Hi Ray,
    thanks for your eleborate reviews on this scope so far. Looking forward to more articles here. Maybe share some experiences with astro photography using this set?
    I am seriously considering to buy the 9¼ Edge HD on the CGEM mount. Every shred of objective info on the scope and the CGEM mount is very much appreciated.
    Thanks again!


  10. Robert,

    I think the 9 1/4 Edge HD on the CGEM mount would be a good choice. I actually wanted this setup but couldn’t wait for the 9 1/4 to come out I guess! Looks like it will start shipping next month, eh?

    Ray Shore

  11. Ray,
    I hope they start shipping next month indeed. {Don’t forget to send one to Europe guys!! :-)}
    On one of the Dutch fora they pointed out that SCT’s are not a very good choise for astrophotography, because these scopes have a small field of view due to their (F10) focal length. What´s your opinion?


  12. Robert,

    SCT’s are good for imaging planets with a webcam. That’s what I use 9 1/4″ for. Probably not the best choice if using a DSLR because of the smaller field of view. Some will use a focal reducer with their SCT to help. A lot of people use their dedicated CCD cameras with an SCT with good success. I like to use my ED80 refractor with my DSLR. It is a good match for that type of camera.


  13. Thanks for your reply Ray. These new Edge HD’s have Fastar capability. Any ideas how that will perform with a DSLR?
    TIA, Robert

  14. Robert,

    No experience with Fastar here, but the numbers turn out good. With a Canon 450D, it would give you 2.2 arc seconds/pixel which is an ideal sampling rate. Also, you will have a wide arc minute field of 162 x 108 which will frame most of the Messier Objects. So the numbers sound good but I’m not sure how the central obstruction (DSLR) will affect imaging. I saw some photos somewhere using the Fastar with the EdgeHD and they looked good.


  15. I have the CGEM on the way from a dealer in California. This will be my first eg mount, as I have had several Celestron fork mount scopes the biggest being a Nexstar11.Your review helped me settle an issue I had on the money side of my dream scope.
    Although I would have loved a C14, along with that scope you need at least a CGE mount or better,big money for me.So I recalled the C11 I had sold a while back(I miss IT) and I decided on a Nexstar C11 carbon fiber with fastar on the Cgem mount. From what you have posted and other reviews,unless I will be dealing with stiff winds or a multitude of heavy attachments to this scope mount setup, the system as purchased should do just fine. I have to remind myself of just what I was capable of doing after I sold my C11, now working with an old Celestar-8 with a Pentax DSLR. I have dozens of photos I was real proud to show around that were quite good,some better than good, with a shaky system that only settles out when you not only keep you hands off it but stand back a few feet using a remote shutter release. Those result should be dupilacted with ease with this new setup and expanded upon, I cant wait.
    I have started a homemade observatory in my yard to house this unit, the dome being an 11 foot fiberglass satelite dish that was given to me. Its big a fairly deep, may work we’ll see.
    Thanks Ray
    Frank fs.gilbert@yahoo.com

  16. Hi Frank,

    Congrats on ordering a CGEM! I am very pleased with mine so far. Are you planning to do some Fastar imaging? Would be interested in seeing the results. Interesting observatory dome. I’d like to see how that turns out.

    Ray Shore

  17. Bruce Jastrow

    I like your review, my CGEM and 9.25 EdgeHD are on order through OPT and should arrive the end of this month (with luck), I also order the Orion Parsec 8300C Astronomical Imaging CCD Camera and that should arrive as well. I own an Orion Atlas and it is a very sound mount. My reasons for ordering the CGEM were the new features and having multiple mounts for 3 refractors and 2 SCT’s. As far as comparison: the tripod on the Atlas has the mount attach to face north (two legs south) and the tripod on the CGEM has the mount face south (one leg face north). Something to consider for star parties. The Atlas has the Vixen style mount (though an adapter can be purchased) and the CGEM has a Losmandy style mount (or I could have this reversed), anyway it is a consideration if you have other OTA’s.

  18. Hello Bruce,

    Quite a nice array of gear! Congrats on getting the CGEM and EdgeHD. One thing you’ll find with the CGEM mount is that you can switch the pin on the mount so that two legs face the north.

    Let us know how that Orion Parsec 8300C works out.

    Ray Shore

  19. Hi, Thanks for your useful review.
    we own a meade LX200R 12″, but its not that impressing in visual observing, which is my job all the time. So I want to upgrade. how would it be if I mount the Tak 150 TOA on CGEM?
    I was searching for a comparison between Celestron C14 and Takahashi new TOA 150, since I’m in a semi light polluted City, my purpose is to search for the most amazing observing Scope, most of my work will be transferring Image live to TV, and visual observing.

    which one of them could give more “WOW” “Eh” words from your point of view.
    I’ll be most likely observing Saturn, Jupiter,Lunar, and most famous bright Clusters and Galaxies to show our customers.

  20. How does the Celestron CGEM mount compare to:

    Losmandy G-8 (probably

    Losmandy G-11

  21. thanks for the review—I just ordered a CGEM from Amazon, and then decided to search for reviews—it confirmed my choice. I currently use a CG5GT and it does have its limitations, but is good for its price. I decided, time for an upgrade, as last night, the plastic housing on the CG5 bent just enough to interfere with the motor. I’m especially happy to read here that the CGEM has a metal housing–I hope I can lift it!

    (note–in part 1 near the end, I believe “phase” should be “faze” 🙂 )

    1. AstroPhotography Tonight


      I did a lot of astrophotography with my CG5 but the CGEM is definitely a nice improvement. It is much heavier than my CG5 was. I think you will like the CGEM!

      Ray Shore

  22. Hey Ray,

    Just wanted to drop you a line when I saw this review. I’m the guy that purchased your LX200 12″, and am having some fun with it. However, I’m quickly realizing that I would like to have a dedicated mount with a wider angle view for astrophotography. I have the Astrotech AT6RC on the way, and am thinking about purchasing the CGEM or Atlas as a mount. Your input is greatly appreciated on this site! Thanks! Take care and clear skies,


    1. AstroPhotography Tonight

      Hey Ryan!!

      I was wondering the other day how things were going with the LX200! That was such a great scope…sometimes I miss it! But I am really liking my CGEM too. Last weekend I took this photo with the ED80 on the CGEM: http://astro.shoregalaxy.com/photos/displayimage.php?pid=157&fullsize=1. So far it seems to be a nice scope for astrophotography. Let us know how things go with the Astrotech. Interesting looking scope and has a great price! Thanks for the comments regarding my site and I hope you keep in touch!! Thanks, Ray Shore

  23. What has not been mentioned so far is the reliability and after-sales service from Celestron. With my CGEM the motorboard broke down and Celestron does not want to provide the local dealer with a spareboard alltough it is within the guarantee period..
    Celestron want the complete mount back which is ridicules because shipment to and from overseas cost more than a new mount. Ergo: don’t buy a CGEM mount unless your dealer has spare boards on stock.

    1. AstroPhotography Tonight

      Sorry to hear that you have had problems with your CGEM mount. It is unfortunate that you have to send it back! I have heard of a couple other instances where the CGEM had to be shipped back to Celestron and there was a long waiting period. Did it break down after the warranty expired through the local dealer? Thank you for your input. Ray Shore

  24. Many thanks for the review, Ray.

    I’ve heard so many bad things about this mount though. Too many people seem to have had bad luck. I hope I am not going to be among them as it still seems the best there is in my price range.
    Still undecided about the CGEM vs the Orion Atlas version.
    Thanks for pointing out some of the salient differences.

    1. AstroPhotography Tonight

      No problem Terry. I had a tough time deciding between the CGEM and Atlas as well. I saw a couple of postings where there were problems with the CGEM hand controllers. But then, there were plenty of CGEM owners that were very pleased. I’ve had my CGEM for over a year now and I’m quite happy with it. Using the Orion autoguider, I’m taking 20 minute exposures without any problems. The one thing I don’t like about the CGEM (that was not a problem with my LX200), is that you have to do an alignment for it to track. So if I want to just turn the scope on and point it to Jupiter manually, it doesn’t track. I have to go through the alignment process first. One could leave it in hibernate mode but it seems like you shouldn’t have to. The good thing is, I’m getting really fast at aligning the CGEM so it’s not a huge issue. And the goto on this scope is amazing. Thanks, Ray Shore

  25. I put up a poll few months ago on the CGEM yahoo group relating to quality issues with CGEM and satifisfaction of buyers of the mount. Hand control issues have been known from some lots of hand controls. The poll though showed about 86% happy rate with about 42-60 votes from what I recall. Just some FYI on quality of the mount for those who like to see some data from polls. I think with any name brand mount there will always be those who have issues, much like a car lemons get through. I don’t like on the CGEM groups page how it seems there always one or two naggers who constantly bitch about the lousy service, the purpose of the groups is to offer solutions to issues and improvements to the mount. I have been member of LX-200 groups and can say the amount of information I learned from the groups was incredible, and helped me fine tune my lx-200. But like any group there are naysayers.

    I think Ray has done a fine job so far representing the CGEM capabilities, and always love the articles he posts here! This site has been invaluable as a CGEM and astroimaging resource to me! Keep up the great work Ray!

  26. Larry Donohoe

    Hello- I’m an newbe at stargazing & would like to purchase a telescope & goto mount that I can use to view Planets, galaxies & nebulas as well as wildlife in the National Parks. I setup viewing wildlife from my car so I don’t have to pack the scope any distance. I also would like to do astrophotography as well. I’m about to retirement age so I want a telescope to be a one time purchase. I’ve been looking at the Celestron 9.25 & 11 edgehd & the televue 85. Also the CGEM mount. Would I be able get close to the qulaity of the the views with the TV85 that I could get with the larger Celestron aperatures? Any sufggestions would be appreciated. thx.

  27. hi there ermm did the scope not balance with one weight i just got this scope and the guy said only use one weight but you have 2 on,now have i got it wrong and the guy in the shop or does it not matter if there is one or two weights on ?

    1. AstroPhotography Tonight

      I just tried my CGEM with only one weight (the heavier of the two) and it will not balance. The 9.25″ optical tube is definitely too heavy to balance with just one weight. I only need one weight when I use the smaller ED80 scope though.

  28. Roberto Pontes da Silva

    Hello, I live in Brazil and I have been trying for years to buy a mount like yours, would not you help me?

  29. Hi Ray,
    I just ordered the 9.25 CGEM with EdgeHD. I liked your feedback on your experience with your 9.25 and will input mine when I get up and running.
    Clear skies!

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