Celestron CGEM II 8" EdgeHD SCT GoTo Telescope

Celestron EdgeHD 8-inch SCT (CGE) Optical Tube Assembly

The night sky has always fascinated individuals and with good reason. The heavens are teeming with life, but sadly, most of it is not visible to the naked eye. Now with the study of Astronomy and the invention of telescopes, the moon, stars and planets are all within reach. With the right instruments, there's no telling what you might see.

See the Universe in HD

The Celestron EdgeHD 8-inch SCT Optical Tube Assembly 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. The EdgeHD OTA has an 8-inch aperture with a focal length of 2032 mm. It comes with a 40 mm Plössl 1.25-inch eyepiece, a 9x50 finderscope, and a 1.25-inch mirror diagonal for more comfortable viewing.

True Quality

Many 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.

Improved Performance

Superior 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 Features

In 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, tube vents and Fastar versatility are just three examples of EdgeHD's newest features.

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).

Cooling vents located on the rear cell allow hot air to be released from behind the primary mirror. Each vent has an integrated 95-micron micromesh filter guaranteed to let warm air out without letting dust in.

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 Tested

Every 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 Celestron's rigid quality assurance. This final acceptance test confirms the EdgeHD will perform in the field and deliver high-quality astroimages.