Highlights Experience our best optical performance with EdgeHD's aplanatic, flat field Schmidt-Cassegrain optics for pinpoint stars all the way to the edge of today's largest imaging sensors and widest eyepieces. Aluminum optical tube with tube vents featuring an integrated 50-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. Celestron's premium StarBright XLT coatings provide maximum light transmission. A 9x50 finder scope, 1.25 mirror diagonal for more comfortable viewing, and 40 mm Plössl 1.25 eyepiece are all included. See the Universe in HDEdgeHD is an aplanatic, flat field Schmidt-Cassegrain telescope that produces aberration-free images across a wide visual and photographic field of view. The optical system was designed to reduce more than just off-axis star coma; it also provides an astrograph-quality flat focal plane all the way to the edge of the field of view. True Astrograph QualityMany optical designs that advertise themselves as "astrographs" actually only produce pinpoint stars across a curved focal plane. While this may be acceptable for some visual observing, stars will appear out of focus at the edge when used with the flat chip sensor of a digital camera. EdgeHD optics produce a focal plane more than three-times flatter than a standard Schmidt-Cassegrain telescope and dramatically flatter than competing coma-free designs. This guarantees you visibly sharp stars across some of the largest CCD chips available today. Learn more about EdgeHD technology. Improved PerformanceSuperior edge performance not only creates rounder, more pleasing stars, but actually improves the resolution and limiting magnitude when compared to telescopes of equal aperture. With Celestron's StarBright XLT optical coatings on every surface, EdgeHD optics gives you maximum light throughput across the widest visual and photographic spectrum. Mechanical FeaturesIn addition to EdgeHD's optimized optical design, the telescope tube has been redesigned to make sure you get the most from your optics each and every night. Mirror clutches - Flexible tension clutches hold the mirror in place and reduce image shift when taking long exposure astro-images. Once focused, the flexible rods allow the mirror to be held in place without putting any force or pressure on the mirror assembly, keeping the image centered in the eyepiece (or on the sensor). Tube vents - Cooling vents located on the rear cell allow hot air to be released from behind the primary mirror. Each vent has an integrated 50-mesh filter guaranteed to let warm air out without letting dust in. Fastar versatility - EdgeHD is the most versatile imaging telescope available today. At its native f/10, you can achieve the image scale necessary to capture the smallest of deep sky objects. Add the optional reducer lens-custom-designed for your size EdgeHD tube-and you can increase your field of view without sacrificing optical performance. A Barlow gives you added power for high-resolution planetary, lunar and solar imaging. All EdgeHD optical tubes are Fastar-compatible, allowing the secondary mirror to be removed and replaced with a third party lens accessory for ultra-fast f/2 wide field imaging. Individually TestedEvery EdgeHD that ships has been tested not only for the surface quality of each optical component, but also with a camera and artificial star to ensure the imaging system meets our rigid quality assurance. This final acceptance test confirms the EdgeHD will perform in the field and deliver high-quality astroimages. Specifications Optical Tube Info: Optical Design EdgeHD Aperture 203.2mm (8") Focal Length 2032mm (80") Focal Ratio f/10 Focal Length of Eyepiece 1 40mm (1.57") Magnification of Eyepiece 1 51x Finder scope 9x50 Star Diagonal 1.25" Star Diagonal Optical Tube Aluminum Highest Useful Magnification 480x Lowest Useful Magnification 29x Limiting Stellar Magnitude 14 Resolution (Rayleigh) 0.69 arc seconds Resolution (Dawes) 0.57 arc seconds Light Gathering Power (Compared to human eye) 843x Secondary Mirror Obstruction 64mm (2.5") Secondary Mirror Obstruction by Diameter 31% Secondary Mirror Obstruction by Area 9.77% Optical Coatings StarBright XLT Optical Tube Length 432mm (17") Optical Tube Diameter 238mm (9.37") Optical Tube Weight 14 lbs (6.35 kg) Dovetail CGE Dovetail Bar
