Celestron EdgeHD 14" OTA - CGE Dovetail

The EdgeHD Optical Design: A 42mm Flat-Field Astrograph

The EdgeHD is an aplanatic, flat-field Schmidt-Cassegrain designed to produce aberration-free images across a wide photographic field. Unlike standard SCTs, which produce sharp stars only in the center of a curved focal plane, the EdgeHD system incorporates a two-element lens group in the main baffle tube. This corrects for both off-axis coma and field curvature, producing a focal plane more than three times flatter than a standard SCT.

The flat focal plane keeps stars sharp to the edge of a flat camera sensor. Every EdgeHD passes a final acceptance test with a camera and an artificial star, which checks for sharp images at the center and at each corner of a full-frame (42mm diagonal) frame.

356mm Aperture: 2579x Light Gathering and 0.33" Resolution

The foundation of this telescope's performance is its 356mm (14") primary mirror. This massive aperture provides a light-gathering power 2579 times that of the unaided human eye, and the limiting stellar magnitude is 15.3.

The Dawes limit is 0.33 arc seconds, and every EdgeHD should resolve double stars to the Dawes limit and reveal the Cassini Division in Saturn's rings on a night of good seeing. StarBright XLT coatings on every surface give maximum light throughput.

Imaging Versatility: Native f/11, Optional Reducer, and Fastar f/2

The EdgeHD 14" is an exceptionally versatile imaging platform, capable of operating at three distinct focal ratios. At its native 3910mm focal length (f/11), it gives the image scale to capture the smallest deep-sky objects. The EdgeHD 1400 forms its best images 146.05mm (5.75") behind the 3.290"x16 tpi rear thread.

For a wider perspective on larger deep-sky objects, the optional, custom-designed EdgeHD 0.7x Reducer Lens (#94240) is a five-element lens that widens the field and shortens exposures, attaching to the rear thread at the same 146.05mm back focus. All EdgeHD tubes are also Fastar compatible: the secondary mirror can be removed and replaced with a third-party lens accessory for ultra-fast f/2 wide-field imaging.

Mechanical Precision: Mirror Clutches

Beyond its optics, the EdgeHD 14" tube is mechanically optimized for long-exposure astrophotography. Flexible tension clutches hold the mirror in place and reduce image shift during long exposures. After achieving focus, you turn the two mirror lock knobs clockwise until tight, and loosen them again before refocusing.

These clutches hold the mirror assembly without putting force or pressure on it, keeping the image centered in the eyepiece or on the sensor.

Thermal Stability: Vented Tube for Faster Acclimation

A large telescope must reach thermal equilibrium with the ambient air to deliver its sharpest images. Cooling vents on the rear cell let hot air out from behind the primary mirror.

Each vent is covered with an integrated 50-mesh filter, which allows warm air to flow out without letting dust or debris enter the optical tube.

Mounting the 46 lb OTA: CGE Dovetail

The EdgeHD 14" optical tube assembly weighs 46 lbs (21 kg) and has a length of 787mm (31"). It attaches to mounts via a CGE-style (Losmandy-D compatible) dovetail bar. Celestron sells the EdgeHD 14 as a kit on its CGX-L mount, whose dual saddle takes the CGE bar.

Visual Observing: From 51x Wide-Field to 840x Planetary Views

While designed as an astrograph, the EdgeHD 14" is a superb visual instrument. The included 23mm eyepiece gives 170x, and the highest useful magnification is 840x.

For finding objects and observing large star clusters, the lowest useful magnification is 51x. The package includes a 9x50 finderscope and a 2" star diagonal with a 1.25" adapter. On deep-sky objects, viewed with a high-quality eyepiece, EdgeHD star images appear sharp and well defined to the edge of the field.