Celestron EdgeHD optics: corrected image, sharp to the edge!
EdgeHD is Celestron's optical design designation, the "Aplanatic Schmidt-Cassegrain Telescope." After more than 50 years of success, Celestron is revolutionizing the classic Schmidt-Cassegrain telescope.
EdgeHD (English: "Edge High Definition") telescopes are true astrographs. This optical system delivers sharp, distortion-free images right to the edge of the field of view. Not only is coma corrected off the optical axis, as with other so-called "coma-free" optical designs available on the market, but also curvature of the field.
Many optical systems are propagated as "astrographs". They obtain images of stars with the desired precision, but along a curved image plane. When taking pictures with cameras, the result is a conspicuous field curvature that increases towards the edge of the field and becomes more noticeable the larger the sensor. The stars inflate into small rings ("doughnuts") towards the edge. In addition to coma, Celestron Edge HD telescopes also correct for this curvature of field all the way to the edge. This also significantly improves resolution and cut-off size compared to competing optics with a similar aperture.
Celestron's XLT multi-coating also helps EdgeHD optics achieve a significant increase in performance compared to similar systems on the market.
The mechanics and tube of the Edge HD telescopes have been completely revised:
Mirror locks hold the main mirror in any focus position without putting pressure on the optical elements. The image always remains stable on the chip, even with long exposure times.
The ventilation openings behind the main mirror ensure rapid air exchange, so that the optics cool down quickly without equal. Thanks to an air filter system, no dust enters the tube.
The CGEM II mount:
Celestron has updated the popular CGEM mount. Version 2 has a more stable tripod, USB connection, double dovetail clamp for Losmandy and Vixen standards, improved ergonomics and firmware!
What hasn't changed is what has proven itself with CGEM over the years: it's still a serious mount for astrophotography, safely carrying Celestron's SC optics up to an 11-inch (279-mm) aperture. ) for photographic requirements. Of course, you can also combine the CGEM with telescopes from other brands, whether they are medium-sized refractors or Newtonian telescopes. The double saddle clamp is suitable for the two common formats of prism rails (also called dovetail rails). The saddle clamp has two large non-slip screws that can also be easily operated while wearing gloves. Since the clamp presses on the dovetail bar across its full width and not just on the screws, the rail is not damaged during mounting.
Other advantages of the CGEM II:
The tripod legs have markings so you can extend the legs to a consistent length and it's also easy to remember your preferred length.
Built-in Celestron All-Star Polar Alignment to align the mount with the help of any star. So you don't need a polar finder and you don't have to contort yourself to find your way north. You don't even need a clear view of the North Star! The post height adjustment screw is large and easy to grip. This is an important advantage, since the pole height adjustment has to be performed under the load of the optics.
Large database of all popular DeepSky objects, cataloged by name and catalog number; the best-known double, triple and quadruple stars, as well as variable stars and solar system objects.
Permanently Programmable Periodic Error Correction (PEC) - Periodic Screw Error Correction
16-character, two-line LCD hand control with backlit buttons. The hand controller has a USB port for easy connection to PC for mount and hand controller firmware updates.
Tracking beyond the meridian: Up to 30°, so long exposure astrophotography doesn't have to be stopped suddenly.
In Celestron's range of modern equatorial GoTo mounts, the CGEM II sits between the AVX and CGX mounts. We are happy to recommend the budget entry-level AVX, which already has all the benefits of NexStar+ electronics, but is not mechanically designed for large optics. The CGX mount meets the highest demands of astrophotographers, even with heavy equipment. Finally, the CGEM II is an excellent compromise between load capacity, performance and price. It is the workhorse of demanding astrophotographers.
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