The Celestron CGEM 800 HD combines Celestron?s CGEM Computerized Equatorial mount with its 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.
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.
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).
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.
New aplanatic Schmidt telescope design produces aberration-free images across a wide field of view
Mirror tension locks hold the primary mirror in place and reduce image shift
Cooling vents allow hot air to be released from behind the primary mirror
Fastar compatible for fast f/2 imaging
Computerized Mount Features
Proven NexStar computer control technology
40,000 object database with over 100 user-definable objects and expanded information on over 200 objects
Redesigned electronics deliver constant regulated power to the motors making them capable of driving the telescope even when not perfectly balanced.
New ?All-star? Polar alignment uses any bright star for a quick and accurate Polar alignment
Software Features include: Mount Calibration, Database Filter Limits, Hibernate, five Alignment Procedures
Flash upgradeable hand control software and motor control units for downloading product updates over the Internet
Meridian preference for slewing ? allows you to approach an object from the side of the Meridian that maximizes tracking (and imaging) time.
Solar System alignment method ? allows you to align your telescope and view the moon and planets during the day
Custom Rate 9 feature allows you set maximum slew rate
Tandem mode allows you to star align the mount even when positioned for tandem scope use
Custom database lists of all the most famous deep-sky objects by name and catalog number: the most beautiful double, triple and quadruple stars; variable stars; solar system objects and asterisms
Permanent Programmable Periodic Error Correction (PEC) ? corrects for periodic tracking errors inherent to all worm drives
Drive Motors ? Low Cog DC Servo motor with integrated optical encoders offer smooth, quiet operation and long life. The motor armatures are skewed to minimize cogging which is required for low speed tracking
Internal Cable wiring for trouble-free setup and transportation
Designated six-pin RJ-12 modular jack, ST-4 compatible guide port
Autoguide port and Auxiliary ports located on the electronic plate for long exposure astrophotography
Double-line, 16-character Liquid Crystal Display Hand Control with backlit LED buttons for easy operation of goto features
RS-232 communication port on hand to control the telescope via a personal computer
Includes NexRemote telescope control software, for advanced control of your telescope via computer
GPS compatible with optional SkySync GPS Accessory
Precision machined 40 mm diameter steel Polar shafts supported by multiple tapered roller bearings and ball bearings
Secure power plug ensures that the mount?s power source is not accidentally disconnected
Alignment Procedures: 2-Star Align, Quick Align, 1-Star Align, Last Alignment, Solar System Align
Aperture (mm): 203.2 mm (8 in)
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
Focal Length: 2032 mm (80 in)
Focal Length of Eyepiece 1: 40 mm (1.57 in)
Focal Ratio: 10
GPS: Optional SkySync GPS Accessory
Highest Useful Magnification: 480 x
Light Gathering Power: 843 x
Limiting Stellar Magnitude: 14
Lowest Useful Magnification: 29 x
Magnification of Eyepiece 1: 51 x
Mount Type: CGEM Computerized Equatorial
Optical Coatings: Starbright XLT Coating
Optical Design: EdgeHD
Optical Tube Length: 17 in (432 mm)
Power Requirements: Car battery adapter
Resolution (Dawes): 0.57 arc seconds
Resolution (Rayleigh): 0.69 arc seconds
Secondary Mirror Obstruction: 11%
Secondary Mirror Obstruction: 2.7 in (69 mm)
Slew Speeds: Nine slew speeds
Star Diagonal: 1.25
Total Telescope Kit Weight: 88 lbs (40 kg)
Tracking Modes: EQ North and EQ South
Tracking Rates: Sidereal, Solar and Lunar
Tripod: Adjustable, Stainless Steel
Warranty: 2-year Telescope Warranty
Weight of Counterweights: 1 x 17 lbs