Engineered to deliver sharp and clear distortion-free views, the Celestron EdgeHD CGE 8" f/10 Aplanatic Schmidt-Cassegrain Telescope is an ideal choice for observation, astrophotography, and imaging objects within or beyond our solar system. It features an aplanatic Schmidt-Cassegrain optical system consisting of a corrector plate, a spherical primary mirror, and a secondary mirror along with a set of field-flattening lenses integrated into the baffle tube. Complementing the EdgeHD system is the proprietary StarBright XLT optical coating system, which improves light transmission and reflectivity across the entire visual spectrum. The combination of EdgeHD and StarBright XLT produces bright and clear high-resolution images with true color rendition across the entire field of view without distortion, aberrations, or off-axis comas.
Optimized for imaging, the internal focusing system features mirror support clutches to ensure proper alignment and mirror locks to avoid accidental defocusing during long-exposure astrophotography. The optical tube is outfitted with a standard 1.25" visual back to make it easier to find eyepieces, accessories, and imaging gear. For visual observations, a 1.25" star diagonal is included along with a 40mm Plössl eyepiece that yields 51x magnification. The EdgeHD 8" is offered here without a mount or tripod for users who already have a reliable support system and are looking to upgrade or add to their existing gear, but comes with a large CGE dovetail plate that is compatible with Losmandy-style saddles.
- 8" (203.2mm) aperture
- f/10 focal ratio
- 2032mm effective focal length
- Aplanatic Schmidt-Cassegrain optical design
- EdgeHD field-flattener aplanatic design eliminates spherical aberration, field curvature, and off-axis star coma to improve resolution, sharpness, and clarity across the entire field of view, especially at the edges
- Diffraction-limited SCHOTT glass reduces internal light loss to improve color, clarity, and sharpness
- StarBright XLT optical coatings
- Flexible tension clutches hold the primary mirror in place to reduce image shift without putting any force or pressure on the mirror assembly, keeping subjects centered
- Internal mirror locks prevent accidental adjustment to focus—important during long-exposure astrophotography
- Integrated 95-micron mesh filter allows hot air to be released from behind the primary mirror without dust getting in, to prevent mirror distortion due to uneven surface temperatures
- Resolution: 0.69 arcsec (Rayleigh); 0.57 arcsec (Dawes)
- Secondary mirror obstruction: 2.7" (69mm); 34% by diameter; 11% by area
- Maximizes light transmission through optical path
- Improves color rendition, contrast, sharpness, resolution, and brightness
- Broadband system provides flat wavelength transmission across the entire visual spectrum
- Multi-layer mirror coatings with layers of aluminum, SiO2 (quartz), and TiO2 (titanium dioxide)
- Multi-layer anti-reflective corrector plate coatings with layers of MgF2 (magnesium fluoride) and HfO2 (hafnium dioxide); hafnium has a wider band-pass than the commonly used titanium
- High-transmission water white glass corrector plate limits light loss due to internal absorption
- OTA only; mount and tripod required for proper use
- Large CGE (Losmandy-style) dovetail plate
- Standard Schmidt-Cassegrain telescope (SCT) threads
- 1.25" eyepiece/accessory holder
- Use for prime focus or projection astrophotography with optional adapters
Eyepiece:
- Plössl lens configuration
- 1.25"-diameter barrel
- Accepts most 1.25" eyepiece filters
- 40mm focal length yields 51x power
Diagonal:
- 90° angle puts head in comfortable viewing position
- Threaded for direct connection to OTA without the need for the visual back
- 1.25" eyepiece/accessory holder
- Star diagonal corrects image horizontally, but not vertically
Finderscope:
- Low 9x magnification preserves wide field of view to more easily find alignment or guide stars
- Large 50mm aperture helps to see dimmer objects and stars for easier star-hopping navigation