Celestron CGEM II 1100 EdgeHD Telescope

11" EdgeHD Optics: A 0.42 Arc Second Flat-Field System

The EdgeHD optical design is an aplanatic Schmidt-Cassegrain that produces aberration-free images across its entire 42mm image circle, fully illuminating full-frame camera sensors. Unlike standard Schmidt-Cassegrains, the EdgeHD system ensures a flat focal plane, rendering stars as sharp points from the center of your eyepiece to the edge of your camera sensor. With a light gathering power 1593 times that of the human eye and premium StarBright XLT coatings, this 11" aperture reveals faint galaxies and resolves fine detail in planetary cloud bands.

Imaging-Focused Design: Clutches, Vents, and f/2 Versatility

Celestron engineered the EdgeHD tube with specific features for astrophotography. Flexible tension clutches hold the primary mirror securely to reduce image shift during long exposures, and integrated cooling vents on the rear cell allow hot air to escape without letting dust in, ensuring thermal equilibrium and sharper images. For ultimate flexibility, all EdgeHD optical tubes are Fastar-compatible, allowing you to replace the secondary mirror with a third-party lens accessory to convert the telescope into an ultra-fast f/2 wide-field imaging system.

CGEM II Mount: 40 lb Capacity and All-Star Alignment

The CGEM II equatorial mount provides the stability required for a large optical tube. Its 40 lb instrument capacity easily handles the 28 lb OTA plus cameras and accessories, all supported by a heavy-duty tripod with 2" diameter steel legs. Celestron’s innovative All-Star polar alignment routine allows you to use any bright star to achieve an accurate alignment, saving you time in the field. For objects near the meridian, the mount tracks well past this line, preventing interruptions during critical long-exposure images.

NexStar+ Controller: 40,000+ Objects and PPEC

The system is commanded by the NexStar+ hand controller, giving you access to a database of over 40,000 objects. For imagers, the mount features Permanent Periodic Error Correction (PPEC), which allows you to train out the periodic errors inherent in the worm gears and store the corrections for future sessions. With nine slew speeds, sidereal, solar, and lunar tracking rates, and an integrated autoguider port, the CGEM II is fully equipped for serious deep-sky imaging.

CGEM II 1100 vs. 9.25" EdgeHD: Aperture vs. Portability

Choosing between the 11" and 9.25" models on the CGEM II mount comes down to a trade-off between light-gathering power and portability. The decision hinges on your observing goals and physical constraints.

• Light Gathering: The 11" EdgeHD has 40% more light-gathering area than the 9.25" model. This translates directly to brighter images of faint nebulae and galaxies, and shorter exposure times for astrophotography.
• Weight and Portability: The 11" optical tube weighs 28 lbs, while the 9.25" OTA is significantly lighter at 20 lbs. For those who frequently travel to dark sky sites, the 8 lb difference can be a major factor in setup and transport convenience.
• Resolution: While both systems deliver exceptional detail, the larger 11" aperture provides a higher theoretical resolution limit (0.42" vs. 0.5" Dawes' Limit), giving it an edge on planetary and lunar observing when seeing conditions permit.