Celestron CGEM II 925 EdgeHD Telescope

EdgeHD Optics: A 0.49 Arc Second Aplanatic, Flat-Field System

The EdgeHD optical system is an aplanatic Schmidt-Cassegrain design that produces aberration-free, pinpoint stars across its entire 42mm image circle. It reduces more than off-axis star coma, giving an astrograph-quality flat focal plane more than three times flatter than a standard Schmidt-Cassegrain, so stars stay sharp to the edge of a flat camera sensor.

Superior edge performance improves resolution and limiting magnitude compared with telescopes of equal aperture, and StarBright XLT coatings on every surface give maximum light throughput. Every EdgeHD passes a final acceptance test with a camera and an artificial star.

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

The EdgeHD 9.25" optical tube is engineered with mechanical features that directly address the challenges of long-exposure astrophotography. Flexible tension clutches secure the primary mirror after focusing, significantly reducing image shift during an imaging sequence. Cooling vents on the rear cell let hot air out from behind the primary mirror.

• Mirror Clutches: Flexible rods hold the primary mirror in place after focusing without putting force on the mirror assembly.
• Tube Vents: Let warm air out from behind the primary mirror. Each vent has an integrated 50-mesh filter to keep dust out.
• Fastar Versatility: All EdgeHD optical tubes are Fastar-compatible. By replacing the secondary mirror with an optional third-party lens accessory, you can convert the telescope into an ultra-fast f/2 wide-field imaging system.

CGEM II Mount: 40 lb Capacity and Ergonomic Design

The redesigned CGEM II carries Celestron's higher-end SCT tubes up to 11" securely and vibration free; the 9.25" EdgeHD tube weighs 21 lbs. The tripod has 2" diameter steel legs, large altitude and azimuth knobs make polar alignment adjustments quick, and internal RA and DEC motor wiring gives a clean, trouble-free setup.

• Instrument Load Capacity (40 lb): Carries the 21 lb 9.25" OTA with room to spare.
• Dual Saddle Plate: Compatible with both CGE (Losmandy D style) and CG-5 (Vixen style) dovetails, the 9.25" EdgeHD comes on a CGE bar.
• Tripod (2" Steel Legs): Features graduated markings on the lower leg sections, making it easy to extend the legs to the same height for a level setup every time.

NexStar+ Intelligence: 40,000+ Objects and All-Star Polar Alignment

The brain of the CGEM II is the proven NexStar+ hand controller, giving you access to a database of over 40,000 celestial objects. The mount features Celestron's innovative All-Star Polar Alignment, which lets you choose any bright star while the software calculates and assists with polar alignment. For dedicated imagers, Permanent Periodic Error Correction (PPEC) lets you train out the periodic error of the worm gears and stores the recording for future sessions.

The mount can also track objects well past the meridian, for uninterrupted imaging through the best part of the sky. With 9 slew speeds up to 4.5° per second, you can move quickly between targets, while the DC servo motors provide smooth, accurate tracking at sidereal, solar, and lunar rates.

Imaging & Visual Use: 146.05mm Back Focus and Included Accessories

The EdgeHD optics are designed to form their best image at a precise back focus distance of 146.05mm (5.75") from the 3.29"-16 tpi male threads on the rear cell. For visual observation, the system comes ready to use out of the box with a 9x50 finderscope, a 2" star diagonal, a 1.25" adapter, and a 23mm eyepiece that provides 102x magnification.

For astrophotography, the mount is equipped with an autoguide port for connecting a guide camera, and the total kit weight is 99 lbs (45 kg).