Celestron Advanced VX 8" EdgeHD Telescope

EdgeHD Optics: 0.57" Resolution Across a 42mm Flat Field

Unlike traditional Schmidt-Cassegrain designs that are only well-corrected on-axis, the EdgeHD optical system is an aplanatic astrograph designed to eliminate both off-axis coma and field curvature. The result is a flat focal plane that renders stars as sharp, concentrated points from the center to the edge of the field of view. This is critical for modern wide-field eyepieces and large-format imaging sensors.

The 8" model has a 42mm image circle, with optics optimized for the central 28mm, the size of an APS-C sensor; a full-frame sensor (43.3mm diagonal) will show some corner falloff, so take flat frames. With StarBright XLT optical coatings maximizing light transmission, the system achieves a limiting stellar magnitude of 14 and gathers 843 times more light than the human eye, revealing faint details in galaxies and nebulae.

Imaging-Ready OTA: Mirror Clutches, Vents, and f/2 Versatility

Celestron engineered the EdgeHD optical tube for the demands of astrophotography. To prevent image shift during long exposures, two mirror support clutches lock the primary mirror in place after focusing, eliminating movement as the telescope tracks across the meridian. Integrated cooling vents behind the primary mirror allow warm air to escape, reducing tube currents and helping the telescope reach thermal equilibrium with the ambient air more quickly for sharper images.

The 8" EdgeHD is also Fastar-compatible, allowing you to replace the secondary mirror with an optional HyperStar lens assembly. This converts the telescope from its native f/10 into an incredibly fast f/2 wide-field imaging system, reducing exposure times by a factor of 25 and capturing vast swaths of the night sky in a single frame.

Advanced VX Mount: A 30 lb Payload Capacity German Equatorial Platform

The Advanced VX (AVX) is the smallest of Celestron's German equatorial mounts, with many features of Celestron's larger GEMs. It offers a 30 lb instrument load capacity, providing a stable platform for the 14 lb 8" EdgeHD OTA with ample capacity remaining for cameras, guide scopes, and other accessories. The tripod features 2" diameter stainless steel legs for rigid support and minimal vibration.

High-torque DC servo motors drive both axes smoothly, and the hand control's anti-backlash setting compensates for play in the gears. For astro-imaging, the mount features permanently programmable periodic error correction (PPEC), which allows you to record and play back corrections to the worm gear's periodic error, significantly improving long-exposure guiding accuracy.

NexStar+ Control: 40,000+ Objects with All-Star Polar Alignment

At the heart of the AVX is the NexStar+ hand control, your command center for exploring the universe. The internal database contains over 40,000 objects, including the complete Messier catalog and select NGC objects, plus bright double stars, variable stars and asterisms. The dual-line, 18-character LCD screen provides clear feedback, and a built-in USB 2.0 port allows for direct connection to a PC for mount control with the included Celestron PWI software.

The AVX simplifies the most critical setup step with its All-Star Polar Alignment procedure. This routine allows you to use any bright star - not just Polaris - to achieve a precise polar alignment, even if your view of the celestial pole is obstructed. This makes setting up at a dark sky site faster and more accurate, ensuring the mount can track objects precisely from horizon to horizon.

An Imaging Platform with 133.35mm Back Focus

The 8" EdgeHD is optimized for imaging, with a specified back focus distance of 133.35mm (5.25") from the rear cell's 2"-24tpi threads. This generous spacing provides ample room for complex imaging trains that include off-axis guiders, filter wheels, and astronomical cameras. For imagers seeking a wider field of view, the optional EdgeHD 800 0.7x Focal Reducer converts the system to f/7 while maintaining the flat-field, coma-free performance.

• DSLR and CCD Ready: Standard T-adapters place a DSLR camera at the perfect 55mm spacing, and the remaining distance is easily accommodated with standard T-spacers for CCD cameras.
• Autoguider Port: A dedicated autoguide port on the mount allows for direct connection to a guide camera for precise, long-exposure tracking.
• Dual Saddle Plate: The mount head features a dual CG-5 (Vixen-style) and CGE (Losmandy D-style) saddle plate, offering compatibility with a wide range of optical tubes.

8" EdgeHD vs. the Classic 8" SCT: Coma and Field Curvature

While a classic Schmidt-Cassegrain Telescope (SCT) provides excellent, diffraction-limited views at the center of the field, its images degrade toward the edge due to inherent optical aberrations. The EdgeHD design directly corrects for these limitations, offering a visibly superior view for both visual observers and imagers.

• Classic SCT Limitation (Coma): Off-axis stars in a standard SCT appear to have small "tails" or flares, an aberration known as coma. This distorts star shapes, reducing sharpness and resolution away from the center. The EdgeHD's aplanatic design is fully corrected for coma, rendering stars as round points across the entire field.
• Classic SCT Limitation (Field Curvature): A standard SCT focuses light onto a curved focal plane. When you focus on a star in the center, stars at the edge are slightly out of focus. The EdgeHD incorporates field-flattening lenses within its baffle tube, creating a flat focal plane that matches the surface of a modern camera sensor, ensuring edge-to-edge sharpness.