The Telescope Authority
Since 1947

View Shopping Cart

Your Cart is Empty

Celestron CGEM-II 800 EdgeHD Telescope - CE-12017

SKU : CE-12017

- Read
Add to Wishlist

52D158B8-B55E-4DF3-8064-D4A13DFFDDC4 Request stock alerts and we'll let you know when the item is back in stock

Got questions? Click for live chat

  • Rounder, more pleasing stars with improved resolution and limiting magnitude.
  • A 203 mm (8-inch) EdgeHD Corrected Schmidt-Cassegrain Telescope.
  • Produces Aberration-Free Images.
  • Focal Ratio of f/10.
  • Fastar Compatible Down to f/2.
  • Internal Cable Wiring.
  • Smooth and Quite Operation.

Product Details

  • The Celestron CGEM-II 800 EdgeHD Telescope is capable of carrying Celestron's higher-end SCT optical tubes (up to 11-inches) securely and vibration free which is ideal for both imaging and visual observing.

    Superior mount performance combined with superior edge performance not only creates rounder, more pleasing stars but actually improves the resolution and limiting magnitude when compared to telescopes of equal aperture. When it comes to the Celestron HD series coupled with Celestron's StarBright XLT coating group on every surface, EdgeHD optics gives you maximum light throughput across the widest visual and photographic spectrum. It's a vision you'll never forget.

    Features of the Celestron CGEM-II 800 Telescope

    Ergonomic Design 

    The Celestron CGEM-II mount was designed to be ergonomically friendly with large Altitude and Azimuth adjustment knobs for quick and easy polar alignment adjustment. The internal RA and DEC motor wiring provide a clean look and an easy and trouble-free set-up.


    The Celestron CGEM-II series has a new innovative Polar alignment procedure called All-Star (patent pending). All-Star allows users to choose any bright star, while the software calculates and assists with polar alignment. Another great feature of the CGEM-II, sure to please astro-imagers, is the Permanent Periodic Error Correction (PEC) which will allow users to train out the worm gears periodic errors, while the mount retains the PEC recordings. Furthermore, the new mount model is equipped with a dual saddle capable of mounting both predominant kinds of Dovetail.


    For objects near the Meridian (imaginary line passing from North to South), the Celestron CGEM-II mount will track well past the Meridian for uninterrupted imaging through the ideal part of the sky. The CGEM-II mount has a robust database with over 40,000 objects, 400 user-defined programmable objects and enhanced information on over 200 objects.

     800 EdgeHD FEATURES

    • A 203 mm (8-inch) EdgeHD Corrected Schmidt-Cassegrain Telescope
    • EdgeHD aplanatic, flat field SCT optics for pinpoint stars to the edge of the largest imaging sensors and widest eyepieces.
    • Aluminum optical tube with tube vents featuring an integrated 95-micron mesh filter allows hot air to be released from behind the primary mirror.
    • Mirror support knobs hold the mirror in place and reduce image shift during imaging.
    • Versatile design accommodates 3 focal ratios: native f/10, f/7 with the addition of a focal reducer, or ultra-fast f/2 imaging with a removable secondary mirror and third-party accessories.


    • 2-inch steel legs with height index marks for quick leveling.
    • 40,000 object database with over 100 user-definable objects and expanded information on over 200 objects.
    • Internal cabling throughout for worry-free remote operation.
    • Low cog DC Servo motor with integrated optical encoders offer smooth, quiet operation.
    • Able to track past the meridian allowing seamless imaging.
    • Permanent periodic error corrections allow users to train out the worm gears periodic errors once, while the mount retains the PEC recordings.
    • Software features include Mount Calibration, Database Filter Limits, Hibernate, five Alignment Procedures, and user-defined slew limits.
    • Built-in polar alignment program to polar align on any star in the sky.
    • Longer clutch levers to make tightening and loosening of clutches easier.
    • Custom database lists of all the most famous deep-sky objects by name and catalog number.
    • Solar System alignment method allows to view the moon and planets during the day.
    • Permanent Programmable Periodic Error Correction (PEC) corrects periodic tracking errors inherent to all worm drives.
    • Custom Rate 9 feature allows setting maximum slew rate.
    • Tandem mode allows to star align the mount even when positioned for tandem scope use.
    • RS-232 communication port on hand control to control the telescope via a personal computer.
    • Includes NexRemote telescope control software, for advanced control of telescope via computer.
    • Precision machined 40 mm diameter steel Polar shafts supported by multiple tapered roller bearings and ball bearings.
    • GPS-compatible with optional SkySync GPS Accessory.


  • specifications

    Aperture203 mm (8")
    Back Focus133.35mm
    Camera/Eyepiece Connection2”x24 tpi
    Corrected Image Circle42mm
    Dawes Limit0.57 arcseconds
    Dew Shield Size226mm
    Drive TypeLow cog DC servo motors
    Focal Length2032 mm
    Focal Ratiof/10
    Free ShippingYes
    Head DesignEquatorial
    Highest Magnification406x
    Instrument Capacity40 lbs
    Latitude Range15 to 70 Degrees
    Light Gathering Power841x
    Limiting Magnitude15.3
    Mount Head Weight40lbs
    Optical DesignModified SCT
    PortsAutoguide Port
    PortsHand Controller
    PortsUSB 2.0
    Power Consumption12V DC 3.2A
    Secondary Obstruction68.6mm
    Slew Speed5 Degrees Per Second
    Telescope ConnectionDual Vixen & Losmandy
    Total Weight77 lbs
    Tracking RatesLunar
    Tracking RatesSidereal
    Tracking RatesSolar
    Tripod Weight20 lbs
    Tube Diameter226mm
    Tube Length432mm
    Tube Weight14 lbs
    Warranty2 Year Warranty
  • included items

    • Celestron's CGEM-II 800 EdgeHD, 203 mm (8-inch) Aperture Corrected Schmidt-Cassegrain OTA.
    • Celestron CGEM-II (Computerized German Equatorial Mount).
    • Adjustable Tripod with 2-inch Steel legs.
    • Hand Controller.
    • Accessory Tray/ spreader.
    • 1.25-inch Star Diagonal.
    • 9 x 50 Optical Finder.
    • 1.25-inch Eyepiece, 40 mm Plossl (51x magnification). 
    • DC Cigarette Lighter Adapter.
    • (1) Counterweight, 17-pound.
    • CD ROM Software: NexRemote.
    • 2 Year Manufacturer's Warranty.

Product Reviews

Customer Reviews
4.6 Based on 13 Reviews
5 ★
4 ★
3 ★
2 ★
1 ★
Customer Photos
Write a Review Ask a Question

Thank you for submitting a review!

Your input is very much appreciated. Share it with your friends so they can enjoy it too!

Filter Reviews:
    United States United States


    After waiting for months, too many, I got a big package at the door, low and behold, the optic scope... Got the box opened and Wow, nice. I looked it over and was amazed with the tube. I went to mount it on the evo arm mount and the dove tail was too big for the mount, bummer, but after looking the tube over, I took the dove tail off my evolution and swapped them. When I ordered the scope, I said I need the narrow dove tail to fit the mount, ok done deal. Well never happened, but I got the scope any how. Now after mounting and getting it all ready, after READING the manual, took it outside and looked at the moon and what a view, so clear and perfect. I now have to wait for the weather to give me a break here in Hawaii. Now is the problem with the change in weather this year, will have to just wait for the right time. But I am happy with the unit, and have installed my starsence and auto focuser on board which makes it easier to operate. I did get the finder scope with the unit but its more of a problem to use that my laser pointer, and with that pin pointing a star is right on. Thanks to OPT for the Optic 8"HD, very happy to make the move and get it. Its worth the time of waiting, through the Trump screw up and being locked down all this time.

    Tim L.
    United States United States

    What a HUNK!!

    They say once you go Black you’ll never go back!! When this hunk of chiseled steel showed up at my front door .. I knew my nights would never be the same again... bringing better balance into my life and loving a good night under the stars, it’s a match made in heaven.. I love the strong silent types with a rough exterior.

    United States United States

    Good Reliable Mount

    I've had my CGEM II for about a year. I do mostly imaging with it and it tracks very well. Auto guiding is very effective. I usually run sub frames at around 30 second exposures but routinely run them for an hour or more. There is very little error during that time. I mount an 11 inch edge with hyperstar which is about the maximum the mount can handle. However I've never felt like it's overloaded even with camera, guide scope, asiair etc. hanging on it. Balance is important as I find you need to pick your target and then balance it with a slight over heavy on the front end. If you're having any trouble, spend a bit more time with balancing. Definitely a great mount for the price.

    Michael L.
    United States United States

    Great for 2008, not 2021.

    I've had my CGEM II for now about 7 months, and it has been a mess to deal with. I would recommend this mount ONLY if you're doing strict visual observing, and not astrophotography, as this mount is IMPOSSIBLE to guide under 1.5-2" RMS I've hypertuned my mount, and it didn't help much. I'm using it with a C8 Edge HD, so not even loading it up, with perfect balance, and an Off-Axis-Guider, and it cant manage sub arcsecond guiding even on good nights, leaving me to do visual. Summary: A mount that looks sexy, seems promising, but fails to perform like its competitors- for nearly 100$ more, using technology that is far too outdated, (not even a USB port on the thing), and hostile towards astrophotographers using longer focal lengths. If you're looking at this mount, save the hastle, and the nearly 100$ extra for the CGEM, and go grab an EQ6R PRO, as it has a handle (doesn't sound like a lot, but trust me, it is NECESSARY for grab n go.), belt drives (A must for guiding), and so much more. I'm gonna go order my Astro-Physics Mach2GTO-L now.

    OPT Telescopes Celestron CGEM-II 800 EdgeHD Telescope - CE-12017 Review
    Michael L.
    United States United States

    Amazing, Simple, High quality.

    I've had my C8HD for about 5 months now, and all I can say about it are good things. F/10, While slow, can be overcome with long exposures. I'm using it on my Hypertuned CGEM II mount, ZWO OAG, ZWO M42 Filter Drawer, and Optolong CLS and it is having no issue doing exposures over 5> minutes. While it is a larger tube, it is surprisingly easy to handle due to the large CGE plate, and the handlebar that sits on the image train end of the scope, which makes balancing SO MUCH EASIER. Works wonderfully, and I can say without a doubt is probably one of the best scopes on the market. Images: Orion, 15 x 60s, The full rig, and M66 and 65 145 x 30s (poorly processed, one of my first shots with it).

    OPT Telescopes Celestron CGEM-II 800 EdgeHD Telescope - CE-12017 ReviewOPT Telescopes Celestron CGEM-II 800 EdgeHD Telescope - CE-12017 ReviewOPT Telescopes Celestron CGEM-II 800 EdgeHD Telescope - CE-12017 Review
    Donald K.
    United States United States

    Not yet

    I will not have my observatory until March so have not had the scope and mount in observing mode. I have done the finder scope alignment and I do like the spring loading feature on the rear of the mount. The slewing is a little loud in speeds 8 and 9 but pretty quite in the slower speeds. The unit went together easily and is quite robust. I think the lock lever does conflict a little with the knobs to tighten the dovetail, but it is a minor issue. I will put it through it’s paces come spring and maybe do another review.