Celestron CGEM II 1100HD 279mm (11") EdgeHD Aplanatic SC Telescope

Celestron CGEM II 1100HD 279mm (11") EdgeHD Aplanatic SC Telescope

Due to high demand and global product shortages due to the pandemic, please call for availability.

A fresh update to the venerable CGEM mount, the CGEM II has a contemporary, attractive, bold appearance. The CGEM II is capable of carrying Celestron’s higher-end SCT optical tubes (up to 11") securely and vibration free, ideal for both imaging and visual observing. Capable of holding 18.2 kg (40 lbs) of payload and slews at 5° per second for instant pointing to any of the celestial objects in the database.

A pioneer in the manufacture of high-quality low-cost Schmidt-Cassegrain telescopes, Celestron continues to draw customers in with its new Aplanatic Schmidt-Cassegrain optics, nicknamed "EdgeHD", which virtually eliminates coma abberation and field curvature. Stars will appear pin-point from edge to edge, with very low distortion near the edges.

Dual breather ports with 60 micon mesh filters are located behind the primary mirror to help rid the optical tube of undesirable thermal differences while keeping dust out of the equipment. The faster the scope can reach equilibrium, the sooner you can get busy under the stars.

Flexible photographic options, such as prime-focus, eyepiece projection, focal reducers, and piggyback mounts, coupled with the solid wide dovetail (Losmandy style), will take your hobby to the next level.

Dual mirror locks work in concert with the helical focus and primary mirror baffle to prevent unwanted mirror movement over the course of a long exposure.

The CGEM II mount delivers improved tracking, using high-quality gears, drives and bearings, permanent periodic error correction, and tracks well past the meridian (the best part of the sky).

The 40lbs payload capacity of this mount coupled with the 80mm (3") dovetail saddle means you can add a guidescope without overloading the mount.

Celestron is known for innovation, and they continue this tradition with the new "All-Star" polar alignment that does away with the polar finder.

  • Start with a rough polar alignment
  • Perform a two-star alignment and add one calibration star
  • Select "Align Mount"
  • Locate and centre a bright star, preferably high up near the meridian, away from the Zenith, Celestial Pole or E/W horizon
  • Locate the same star in the database
  • Centre the star in a reticule eyepiece, using the mounts azimuth and latitude adjustments
  • Update the computer star alignment


  • EdgeHD optics yield pin-point stars from edge-to-edge with no coma or field curvature
  • StarBright XLT coatings for better light transmission
  • Fastar compatible tube comes with removable secondary mirror for fast f/2 imaging
  • Flexible visual/photographic use
  • Sturdy 80mm (3") dovetail bar
  • Dual cooling ports with 60 micron mesh filters
  • Primary mirror locks eliminate unwanted mirror movement during long exposures
  • Sturdy 80mm (3") dovetail bar
  • Robust CGEM II Equatorial Mount automatically locates and tracks objects with accuracy
  • All-Star polar alignment for accurate setup for astrophotography and excellent goto performance
  • Permanent Periodic Error Correction (PPEC) is non-volatile for error-free tracking with no need to constantly re-record

Optical Specifications

  • Aperture: 279mm
  • Focal length: 2800mm
  • Focal ratio: f/10
  • Optical design: Aplanatic Schmidt-Cassegrain
  • Optical coatings: Starbright XLT
  • Fastar compatible: Yes
  • Eyepiece: 23mm Axiom ocular (2") (122x)
  • Star diagonal: 2" mirror diagonal w/ 1.25" reducer adapter
  • Finderscope: 9x50mm
  • Mounting: 80mm (3") dovetail bar (Losmandy style)

Mount and Tripod Specifications

  • Mount Type: German Equatorial style
  • Polar Finder: sold separately
  • Analog setting circles: not required
  • Dovetail Saddle: Accepts 44mm (1.75") and 80mm (3") dovetail (not included)
  • Steel worm gear and 90mm pitch diameter brass worm wheel
  • Drive Motors - Low Cog DC Servo motor with integrated optical encoders offer smooth, quiet operation and long life
  • Internal cable wiring for trouble-free setup and transportation
  • ST-4 compatible autoguider port
  • Precision machined 40mm diameter steel Polar shafts supported by multiple tapered roller bearings and ball bearings
  • Secure power plug ensures that the Mount's power source is not accidentally disconnected
  • Latitude range: 15° – 70°
  • Heavy duty 2" stainless steel tripod with height index marks for quick leveling
  • Longer clutch levers to make tightening and loosening of clutches easier
  • Tracks past the meridian allowing seamless imaging
  • Celestron two year warranty

Computer Features

  • Proven NexStar computer control technology
  • Flash-upgradeable firmware
  • 40,000 objects in the database including complete Messier, NGC, and IC catalogues
  • 100 user-definable objects
  • Expanded information on over 200 objects
  • Two-line, 16-character LCD with red LED backlighting
  • Buttons are red LED backlit
  • All-star Polar alignment
  • Alignment: Two-star + optional calibration stars, QuickAlign, 1-Star, Last Alignment, Solar System Align
  • Solar System alignment method allows to view the moon and planets during the day
  • Tandem mode allows to star align the mount even when positioned for tandem scope use
  • Nine Slew Speeds: 5°/sec, 2°/sec, 1°/sec, 64x, 16x, 8x, 4x, 1x, .5x
  • Custom Rate 9 feature allows to set maximum slew rate
  • NexRemote advanced telescope control software
  • USB 2.0 port for external computer control and firmware updates
  • ASCOM compatible
  • Software Features include: Mount Calibration, Database Filter Limits, Hibernate, five Alignment Procedures, and user-defined slew limits
  • GPS Upgradable via SkySync GPS Accessory
  • Includes 12v car plug-in adapter
  • Requires 12v DC 3.2A (Tip positive)
  • TheSky® Planetarium software with 10,000 object database, printable sky maps and enhanced images

Weights and Dimensions

  • Optical tube length: 610 mm (24 in)
  • Optical tube weight: 13 kg (28 lbs)
  • Carrying capacity 18.2kg (40lbs) (not including counterweights)
  • Tripod Weight 9kg (20lbs)
  • Mount Weight 18.2kg (40lbs)
  • Counterweight 7.7kg (17lbs)
  • Total Weight: 35kg (77lbs)
  • Mount Height 41cm (16")
  • Tripod Height 85-147cm (33.5-57.8")
  • Tripod Legs Outside Diameter 50mm (2") and 38mm (1.5")