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.

The Celestron Product Development team has released a whitepaper outlining the technology behind EdgeHD. This paper describes the development goals, design decisions, optical performance, and their practical realization in 8-, 9.25-, 11-, and 14-inch apertures. We include cross-sections of the EdgeHD series, comparative spot diagrams for the EdgeHD and competing “coma-free” Schmidt-Cassegrain designs, a table with specifications for visual and imaging, graphics showing how to place sensors at the optimum back-focus distance, and details on the construction and testing of the EdgeHD telescope series.

To download the Celestron EdgeHD Whitepaper, go to the Support & Download tab

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 .

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.