Details
The CGEM 800 HD combines Celestron's newly designed CGEM Computerized Equatorial mount with its new EdgeHD optical system. With over 8 inches of aperture and our premium StarBright XLT coatings, the CGEM 800 HD gives you over 800 times the light gathering power than the unaided eye. Supporting an optical tube of only 13 lbs, the CGEM 800 HD is the lightest and most portable in its class.
New Optical Design
The EdgeHD optical system combines all the compact power popularized by the SCT and combines it with an improved high definition optical system for wide field, astrograph quality images. As a visual instrument, EdgeHD optics delivers pinpoint images even with your widest field eyepiece. You can search for all of the Messier Catalog objects, and see hundreds of other equally interesting NGC, IC and Caldwell objects with amazing clarity. For astroimaging, the EdgeHD optics produce aberration-free images across your favorite CCD or DSLR camera. All EdgeHD optics are designed to produce an extremely flat focal plane precise enough to match the strict tolerances of the largest commercial CCD detectors, allowing all stars to be in tight focus to the very edge of the chip.
Diffraction Limited
Some companies boast that their telescopes give diffraction limited stars in the very center of the field of view. EdgeHD optics not only produce diffraction limited stars on axis, but maintain diffraction limited stars across the entire field of view of many of the most popular astrophotography cameras. Even at the very edge of a DX format camera chip, the EdgeHD 8" delivers star sizes of less than 1.5 arc seconds.
The EdgeHD 8" optics produce a focal plane more than 3 times flatter than the standard equivalent SCT telescope with diffraction limited stars across the entire Nikon 300 or Canon 40D sensor!

Along with the newly designed optics, the EdgeHD also has re-designed mechanics guaranteed to help you get the maximum performance from your instrument.
Features Include:
Mirror Locks – To hold the mirror in place and reduce image shift during imaging.
Tube Vents - Each vent has an integrated 60 micron micro-mesh filter allowing hot air to be released from behind the primary mirror.
Fastar Versatility – All EdgeHD optical tubes are equipped with a removable secondary mirror for fast f/2 CCD imaging. Not only does imaging in the FASTAR configuration allow for exposure times that are 25 times faster than at f/10, but also yields a field of view five times wider. A perfect combination for imaging your favorite wide field objects in a fraction of the time. (FASTAR imaging requires a third party lens assembly in place of the secondary mirror).
Learn more about the benefits and features of this new optical system by going to the EdgeHD web page.
CGEM™ Mount
The CGEM™ mount has a fresh, attractive, bold appearance and is capable of carrying Celestron’s higher-end SCT optical tubes (up to 11") securely and vibration free which is ideal for both imaging and visual observing.
Ergonomic Design - CGEM 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 provides a clean look and an easy and trouble free set up.
Innovation - The CGEM series has a new innovative Polar alignment procedure called All-Star™. All-Star allows users to choose any bright star, while the software calculates and assists with polar alignment. Another great feature of the CGEM, sure to please astroimagers, is the Permanent Periodic Error Correction (PEC) which allows users to train out the worm gears periodic errors, while the mount retains the PEC recordings.
Performance - For objects near the Meridian (imaginary line passing from North to South), the CGEM will track well past the Meridian for uninterrupted imaging through the most ideal part of the sky. The CGEM mount has a robust database with over 40,000 objects, 100 user defined programmable objects and enhanced information on over 200 objects.
Celestron's CGEM mount is the perfect fit between the Advanced Series and CGE Series. Offering the portability of the Advanced Series and the precision of the CGE.
Additional Information
| Optical Design | EdgeHD |
|---|---|
| Aperture (mm) | 203.2 mm (8 in) |
| Focal Length (mm) | 2032 mm (80 in) |
| Focal Ratio | 10 |
| Eyepiece 1 (mm) | 40 mm (1.57 in) |
| Magnification 1 | 51 x |
| Finderscope | 9x50 |
| Star Diagonal | 1.25 |
| Mount | CGEM Computerized Equatorial |
| Optical Tube | Aluminum |
| Tripod | Adjustable, Stainless Steel |
| Power Supply | Car battery adapter |
| Highest Useful Magnification | 480 x |
| Lowest Useful Magnification | 29 x |
| Limiting Stellar Magnitude | 14 |
| Resolution (Rayleigh) | 0.69 arc seconds |
| Resolution (Dawes) | 0.57 arc seconds |
| Light Gathering Power | 843 x |
| Secondary Mirror Obstruction | 2.7 in (69 mm) |
| Secondary Mirror Obstruction by Diameter | 34 % |
| Secondary Mirror Obstruction by Area | 11 % |
| Optical Coatings | Starbright XLT Coating |
| Optical Tube Length | 17 in (432 mm) |
| Telescope Weight | 88 lbs (40 kg) |
| Counterweights | 1 x 17 lbs |
| Motor Drive | Low cog DC Servo motors with encoders, both axes |
| Slew Speeds | Nine slew speeds: 5 °/sec, 2 °/sec, 1 °/sec, 64x, 16x, 8x, 4x, 1x, .5x |
| Tracking Rates | Sidereal, Solar and Lunar |
| Tracking Modes | EQ North and EQ South |
| Alignment Procedures | 2-Star Align, Quick Align, 1-Star Align, Last Alignment, Solar System Align |
| Software Precision | 24 bit, 0.08 calculation |
| Gear | Steel worm gear and 90 mm pitch diameter brass worm wheel |
| Computer Hand Control | Double line, 16 character Liquid Crystal Display; 19 fiber optic backlit LED buttons |
| Database | 40,000+ objects, 100 user defined programmable objects. Enhanced information on over 200 objects |
| Power Requirements | 12 VDC 3.2 Amps |
| GPS | Optional SkySync GPS Accessory |
| Eyepiece 1 Field of View (deg) | .84 ° |
News
- 12/01/2009 - Hot Products 2010
- 11/15/2009 - Hot Product 2010
Knowledge Base
- Will I be able to use my standard Celestron f/6.3 reducer/corrector with an EdgeHD?
- Will I be able to use my standard Celestron SCT T-adapter 93633-A to attach my SLR camera to the EdgeHD?
- How do my EdgeHD mirror support knob flexible tension clutches work? Will they interfere with focusing my scope?
- My CGEM mount is moving in the wrong direction when I use the direction arrows. What is wrong? How can I change the direction of the direction buttons?
- Is there any way to run Celestron's window-based drivers and software on Macs?
- What is the optimized image circle for the EdgeHD optical tube assembly (OTA)?
- I want to use a binoviewer with my EdgeHD optical tube (OTA). What is its back focus distance?
- My Schmidt-Cassegrain cooling fan needs an open baffle tube to work. .How can I cool my EdgeHD optical tube (OTA) since there is now a lens assembly in the baffle tube?
- How do I collimate the EdgeHD?
- My images with a CCD camera are showing black or white streaks on the brighter stars. They are all bloomed out. What's wrong with my scope?
- Where can I download the unified ASCOM drivers for Celestron?
- What is the operating temperature range for Celestron's telescopes?
- What are Fastar and HyperStar? How do they work?
- My NexStar hand control displays "Offset Too Large" when I'm trying to change my scope's alignment. What does this mean? How to I fix the issue?
- My Celestron software won't run on my Windows 7 computer. Help!
- I need information on the RS-232 (serial) commands for NexStar controlled telescopes.
- I have two scopes I want to use side-by-side or tandem with my Celestron CGE - CGE Pro - CGEM - Advanced GT mount. Can I do that?
- How do I balance my CGEM-mount optical tube assembly (OTA) in declination?
- Can I change the position of my CGEM equatorial head on the tripod?
- What is the timetable for shipments on the EdgeHD? What about accessories like the focal reducer?
- My EdgeHD optical tube assembly (OTA) has four small tapped holes along the front rim. What are they for?
- The alignment pin in my new Fastar-equipped SCT is at the 11 o'clock position. Aren't they supposed to be at the 3 o'clock position as viewed from in front of the telescope?
- How do I mount my finderscope bracket on the EdgeHD 800/925/1100/1400 optical tube assembly (OTA)?
- Is the Deluxe Tele-Extender #93643 compatible with my EdgeHD?
- I have a CGEM mount and I need to use it at latitudes below 15 degrees or above 70 degrees. Can I do that?
- How do I use a third party periodic error correction (PEC) program like PEMPro with my Celestron mount?
- How do I use the polar axis finderscope for the CGEM mount?
- What are the instructions for getting my CN-16 or SkySync GPS working with my Celestron GOTO mount?
- I want to permanently pier-mount my CGEM. What size is the hole on the head holding the central rod?
- My CGEM has wires dangling in the polar axis shaft. Will these interefere with the insertion and use of the polar axis finderscope #94224?
- When should I use the CALIBRATE MOUNT utility? What does it do?
- I have a Celestron GOTO scope, a Mac and an autoguider. I want to autoguide with the scope. Is your autoguider port Mac-compatible?
- How do you stop a GOTO slew in progress? Is there a better way than turning off power or pulling the power plug?
- I have a small-chip CCD camera-APC-format DSLR-webcam with an adapter that isn't made for the EdgeHD. What problems will I have with image quality using this system since it's not the optimum spacing?
- The autoguiding port diagram in my manual is different than the diagram for the NexGuide connection. Are these differences important?
- What's a quick summary of All-Star polar alignment with CGEM - CGEM DX, CGE, CGE Pro and Advanced GT Series mounts?
- What is the threading on the outside of my Celestron GOTO mount's power jack?
- What is the size of the threading holding the visual back to my Schmidt-Cassegrain telescope? Is it the same for all Celestron SCTs?
- Miscellaneous Specifications for the CGEM - CGEM DX Mount
- Miscellaneous specifications for the CGEM Mount
Downloads
Manuals
EdgeHD Optics Manual (1.72 MB | PDF)
CGEM Series Manual (4.91 MB | PDF)
Product Info Sheets
EdgeHD Optics Info Sheet (PDF)
Reference Materials
Celestrial Observing (English, French, German, Italian, Spanish) (381.85 KB | PDF)
Astronomy Basics (English, French, German, Italian, Spanish) (2.26 MB | PDF)
Telescope Maintenance (English, French, German, Italian, Spanish) (640.68 KB | PDF)
Telescope Basics (English, French, German, Italian, Spanish) (481.61 KB | PDF)
Software
NexRemote v. 1.7.18 (30 day trial) (21.55 MB | ZIP)
Motor Control Firmware Updates v.2.2.5 (3.57 MB | ZIP)
Hand Control Firmware Updates v.1.1.14 (3.75 MB | ZIP)
Celestron Firmware Manager (CFM) v.1.0.2100 (ZIP)
PEC Tool v.1.0.18 (3.35 MB | ZIP)





