After evaluating numerous design options, Celestron’s solution to the design of this instrument is a 20” (1/2 meter) diameter f/6.8 field-corrected, modified Dall-Kirkham optical assembly that is mounted on a newly designed, massive observatory-class computerized German Equatorial mount.
Celestron’s Modified Corrected Dall-Kirkham design exceeds the off-axis performance of even the Ritchey-Chrétien design. RMS spot sizes at the edge of a 35mm frame remain smaller than a single pixel on the most advanced CCD cameras available to amateurs today.
The optical system also features a conical primary mirror with low thermal mass and three cooling fans to minimize the cool down time. This no-compromise design provides the superb resolving power Dall- Kirkham telescopes are known for, but without the coma and field curvature that has previously limited their wide-field performance.
Because of its flat-field design, you'll find it a joy to use for imaging as well as visual use. The C20 optical system will come standard with Celestron’s advanced StarBright® XLT High- Performance Optical Coatings.
The CGE Pro Mount The tracking accuracy of this observatory-class mount is better than 5 arcseconds peak to valley without enabling the PEC function. The C20 Astrograph mount separates into three components for easier transporting and includes fully integrated electronics as well as Celestron’s renowned and proven NexStar® software. It is also supplied with NexRemote® Pro, a software package that creates models of the mount which yields observatory class pointing accuracy.
In A Class Of Its Own Other high-end telescopes that are in this category, such as the Ritchey- Chrétien, cost many thousands of dollars more and require that the optical tube, mount, and tripod be purchased separately. In contrast, Celestron is offering the C20 Astrograph as a complete package.
The C20 system includes the optical assembly, a carbon-fiber truss system which minimizes refocusing due to temperature changes, high performance computerized German Equatorial mount, and professional class pier/tripod.
The pier will be available in both portable and permanent versions.
The C20 is a system that meets the highest standards Celestron sets for technical innovation, design and engineering superiority, precision performance, and uncompromising optical quality.
For full specifications please request a new full color Celestron Catalogue
Included Accessories Specification Optics: Design: Corrected Dall-Kirkham Aperture: 20" (1/2 m) Focal Length: 3454 mm Focal Ratio: f/6.8 Central Obstruction: 39% Optical Performance: Flat field over 42mm film plane; 6 micron RMS spot size 21mm off axis Weight: 130 lb.
Mount: Type: German Equatorial Instrument Capacity: 160 lb RA Gear Dia.: 11.25" RA Gear tooth count: 360 Dec Gear Dia.: 9" Dec Gear tooth count: 360 Latitude Range: 15º - 60º (optional latitude wedge for 0º - 90º) Tracking Accuracy: 5 arcseconds or less without Periodic Error Correction enabled Weight: 140 lb.
Electronics: Hand Control: NexStar Computerized Hand Control with 40,000+ objects Software: NexRemote Telescope Guidance Software (for PC Control) Power: 12V DC
Read about alternatives to the Celestron C20 Astrograph in the Optics section for telescope reviews, microscope comparisons, binocular reviews and guides to spotting scopes.
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