Celestron EdgeHD Optics

Aplanatic Schmidt-Cassegrain

EdgeHD is a flat-field Schmidt optical system that produces aberration-free images with pinpoint stars all the way to the edge of the field of view. EdgeHD virtually eliminates both field curvature and off-axis star coma, providing an astrograph-quality system at a fraction of the price of competitors.

Aplanatic Schmidt-Cassegrain

EdgeHD is a flat-field Schmidt optical system that produces aberration-free images with pinpoint stars all the way to the edge of the field of view. EdgeHD virtually eliminates both field curvature and off-axis star coma, providing an astrograph-quality system at a fraction of the price of competitors.

True Astrograph Quality

Many optical designs advertise themselves as “astrographs,” but only produce pinpoint stars across a curved focal plane. Even when focused sharply in the center of the field of view, this curved plane cannot bring stars at the edges into focus. The wider the field of view, the more pronounced this defect becomes. This may be acceptable for some visual observing, but when a curved plane is paired with the flat sensor of a digital camera, stars become noticeably out of focus at the edges.

EdgeHD optics produce a focal plane more than three times flatter than a standard Schmidt-Cassegrain telescope and dramatically flatter than other competing designs, guaranteeing visibly sharp stars all the way across the image circle.

Celestron Focal Plane

A curved focal plane cannot produce consistent results on a flat CCD chip. Stars will appear out of focus at the edges.

Improved Performance for Brighter, More Detailed Images

Superior edge performance not only creates rounder stars but actually improves the resolution and limiting magnitude compared to telescopes of equal aperture.

Edge HD optics let you resolve smaller spot sizes all the way to the outer edge, revealing finer detail and greater contrast. Compare the two cropped images below, both taken with a 37 mm chip (52 mm diameter focal plane) camera.

Image Standard SCT

Fig. 1: The off-axis coma inherent in many optical designs (such as the SCT shown above) distorts star images and compromises resolution.

Edge HD Optics

Fig. 2: EdgeHD focuses sharply across the entire FOV, revealing fine detail lost with other systems.

What’s more, EdgeHD optics give you smaller, more concentrated stars so you can see fainter magnitudes than with other equally-sized telescopes. Poor edge quality can spread out starlight so much that the brightness of a star appears the same as the sky background, making it undetectable to your eye or camera. With EdgeHD optics, you can capture the faintest of galaxies all the way to the corner of your full-frame camera chip. Compare the two cropped images below, both taken with a 37 mm chip (52 mm diameter focal plane) camera.

Image Standard SCT Coma

Fig. 1: In telescopes that exhibit off-axis coma, faint starlight can go unnoticed at the edge of the field of view.

Edge HD Optics Coma

Fig. 2: EdgeHD optics resolve faint detail missed in telescopes of equal aperture.

Mechanical Features

Celestron Edge HD Mirror Support

Edge HD Mirror Support

Flexible tension clutches hold the primary mirror in place and reduce image shift. The flexible rods hold the mirror in place without putting any force or pressure on the mirror assembly, keeping your target centered in the eyepiece or chip.

Tube Vents

Tube Vents

Cooling vents located on the rear cell allow hot air to be released from behind the primary mirror. Each vent has an integrated micromesh filter guaranteed to let warm air out without letting dust in.

Fastar Versatility

Fastar Versatility

EdgeHD is the most versatile imaging telescope available today. At its native f/10, you can achieve the image scale necessary to capture the smallest of deep-sky objects. To increase your field of view without sacrificing performance, add the optional EdgeHD reducer lens. Each one is custom-made for your size EdgeHD optical tube and brings your focal ratio down to f/7. A Barlow lens provides additional magnification for high-resolution planetary, lunar, and solar imaging. And, of course, all EdgeHD optical tubes are Fastar-compatible for ultra-fast f/2 wide field imaging. Each EdgeHD tube is fitted with a removable secondary mirror and is opto-mechanically aligned on a laser bench to ensure it is axially symmetric in any configuration.

Easy Collimation

Easy Collimation

Guarantee ideal performance every time. Edge HD’s precision-machined mechanics and a spherical secondary mirror make collimation simple and accurate.