The Celestron GEM II 800 8" f/2.0 Rowe-Ackermann Schmidt GoTo EQ Astrograph is a combination of a powerful astrophotography optical tube assembly (OTA) and a solid and stable equatorial mount to give users the ability to capture near- and deep-sky objects like the Moon, planets, nebulae, galaxies, clusters, and binary stars. The smaller optical tube weighs just 17 pounds, leaving extra payload capacity for guide scopes, imaging rigs, and other accessories. This highly portable and capable combination is designed for easy travel to remote observation sites.
Optical Performance
- 203mm (8") diameter aperture enables near- and deep-sky viewing without being prohibitively large or heavy for easy transport to viewing locations
- 400mm focal length helps to produce a fast focal ratio
- Fast f/2.0 focal ratio requires significantly lower exposure times versus slower ratios to produce the same results
- Rowe-Ackermann Schmidt astrograph (RASA) design is purpose built for astrophotography and imaging performance, and is not recommended for visual use
- Proprietary StarBright XLT fully multi-coated optical system
- Four-element rare-earth glass for true color rendition without aberrations across the entire field of view
- Wide 390-800nm spectral range improves images of deep space objects like galaxies and nebulae
- Image circle: 22mm (0.86")
- Resolution: 0.68 arcsec (Rayleigh), 0.57 arcsec (Dawes)
- Back focus: 25mm (0.98") with included camera adapter, 29mm (1.14") from top of threaded collar
- Optical window can be removed and replaced with optional filters such as a light pollution filter
- Integrated cooling fan brings optical system to ambient air temperature for better performance
- Runs on eight user-supplied AA batteries or optional 12VDC power adapter
StarBright XLT Coating System
- Multi-layer mirror coatings made from layers of aluminum, SiO2 (silicon dioxide), and TiO2 (titanium dioxide)
- Reflectivity is flat across the light spectrum, for both astrophotography/astro-imaging
- Multi-layer anti-reflective coatings made from layers of MgF2 (magnesium fluoride) and HfO2 (hafnium dioxide)
- High-transmission water white glass corrector lens with 97.4% light transmission
Focuser
- Focusing system moves primary mirror forward and back to achieve tack-sharp images
- Ultra-stable design minimizes unwanted lateral movement of the primary mirror when focusing or slewing
- Fine adjustments for precise focusing, approximately 30 turns of the knob runs through the focus range
Mounting
- OTA only, mount and tripod required for proper use
- Includes large CGE/Losmandy-D dovetail plate for use on larger more stable mount heads
- Weight: 17 pounds
Included Accessories
- Standard M42 camera T-adapter accepts most camera-specific T-rings to directly mount DSLR and mirrorless cameras
- CCTV/Imager C-thread adapter accepts most camera-specific video T-rings to mount imaging and video cameras
- Battery pack takes eight user-supplied AA batteries to power the integrated cooling fan
Optical Tube Assembly
Optical Design RASA
Aperture 203 mm / 8"
Focal Length 400 mm
Focal Ratio f/2
Focuser Internal
Diagonal None
Finderscope None
Mounting System Losmandy Style
Optical Tube Dimensions 24.7 x 9.3" / 62.7 x 23.6 cm
General
Batteries 8 x AA
Adapter 12 VDC (Not Included)
GPS No
Wi-Fi No
Weight 17 lb / 7.7 kg
Packaging Info
Package Weight 24.185 lb
