Celestron Schmidt-Cassegrain telescope SC 235/2350 EdgeHD 925 OTA (16401)

The Celestron EdgeHD is an aplanatic Schmidt-Cassegrain telescope designed to deliver distortion-free, sharp images across the entire visual and photographic field of view. Unlike standard Schmidt-Cassegrain designs, EdgeHD telescopes correct both off-axis star coma and field curvature, making them true astrographs. This ensures pinpoint stars and a flat focal plane, ideal for modern imaging sensors.

Many optical systems marketed as "astrographs" produce sharp stars only across a curved focal plane. While acceptable for visual use, this curvature causes stars at the edges to appear out of focus when using flat imaging sensors. EdgeHD optics provide a focal plane that is over three times flatter than standard Schmidt-Cassegrain telescopes and significantly flatter than competing coma-free designs. This guarantees visibly sharp stars across even the largest CCD sensors.

The EdgeHD also improves resolution and limiting magnitude compared to telescopes of similar aperture. The StarBright XLT coatings on every optical surface maximize light throughput, enhancing performance for both visual and photographic use.

Enhanced Mechanical Features

• Mirror Clamps: Flexible tension clutches hold the primary mirror securely in place without applying pressure, reducing image shift during long exposures. This ensures stable imaging with the target remaining centered.

• Tube Vents: Cooling vents on the rear cell allow hot air to escape from behind the primary mirror. Each vent includes an integrated micromesh filter to release warm air while preventing dust entry.

• Fastar Compatibility: The EdgeHD is highly versatile, supporting multiple focal ratios. At its native f/10, it provides excellent image scale for small deep-sky objects. With an optional reducer lens, the focal ratio can be reduced to f/7 for a wider field of view without sacrificing performance. Additionally, all EdgeHD OTAs are Fastar-compatible, allowing the secondary mirror to be replaced with third-party accessories for ultra-fast f/2 wide-field imaging.

Precision Design
EdgeHD telescopes feature precision-machined mechanics and a spherical secondary mirror for easy collimation. Each unit undergoes rigorous quality assurance testing, including imaging with a camera and artificial star, to ensure optimal performance in the field.

Included with the Telescope:

• Optical Tube Assembly (OTA) with 235mm aperture and 2350mm focal length

• Axiom LX 23mm eyepiece (2")

• 2" star diagonal (90°) with 1.25" adapter

• Mounting rail (Losmandy-style prism rail)

• 9x50 straight-view finder scope

Specifications

Optics:

• Type: Reflector (EdgeHD Schmidt-Cassegrain)

• Aperture: 235mm

• Focal Length: 2350mm (f/10)

• Resolving Capacity: 0.49 arcseconds

• Light Gathering Power: 1127x compared to the human eye

• Maximum Useful Magnification: 470x

• Tube Length: 559mm; Construction: Full tube; Weight: 9.5kg

Reflector Details:

• Secondary Mirror Diameter: 85mm

• Secondary Mirror Obstruction: 36%

Focuser:

• Type: SC thread with 2" eyepiece connection

Mount:

• Type: OTA only (no mount included)

Included Accessories:

• Eyepiece (2"): Axiom LX 23mm eyepiece

• Finder Scope: 9x50 straight-view finder scope

• Diagonal Mirror: 2", 90° star diagonal with 1.25" adapter

• Mounting Rail: Losmandy-style prism rail

General Information:

• Series: OTA

• Total Weight: 9.5kg

Recommended Use

The EdgeHD telescope is ideal for advanced users and observatories due to its premium optics and compatibility with astrophotography equipment but is not recommended for beginners. It excels in lunar/planetary observation, deep-sky exploration of nebulae and galaxies, and high-quality astrophotography but is not suitable for solar observation unless used with an appropriate solar filter.