Celestron EdgeHD 11" OTA - CGE Dovetail

EdgeHD Optics: A 0.42 Arc Second Flat-Field System

The core of the EdgeHD 11" is its aplanatic, flat-field Schmidt-Cassegrain optical system, designed to produce aberration-free images from the center to the edge of the field. Unlike standard Schmidt-Cassegrains that produce sharp stars on a curved focal plane, the EdgeHD optics project onto a plane more than three times flatter. This design ensures that when you use a camera with a flat digital sensor, stars remain tight, round, and in focus across the entire 42mm image circle, fully illuminating even large full-frame chips.

With a Dawes' limit resolution of 0.42 arc seconds, this optical tube has the resolving power to split tight double stars and reveal fine detail in planetary cloud bands. Superior edge performance not only creates more pleasing star fields but improves the effective resolution and limiting magnitude compared to other designs of the same aperture.

Unmatched Versatility: Native f/10 and Ultra-Fast f/2 Imaging

The EdgeHD 11" is Celestron's most adaptable imaging platform. At its native 2800mm focal length (f/10), you have the image scale needed to capture fine details in small planetary nebulae and distant galaxies. For wider-field targets, an optional, custom-designed 0.7x reducer lens can increase your field of view without compromising the flat-field optical correction.

For the ultimate in wide-field imaging, all EdgeHD tubes are Fastar-compatible. By replacing the secondary mirror with a third-party lens accessory like the Starizona HyperStar, you can convert the instrument into an ultra-fast f/2 imaging system. This allows you to capture vast nebulae like the North American Nebula (NGC 7000) or the Heart Nebula (IC 1805) with dramatically shorter exposure times.

Astrograph-Ready Mechanics: Mirror Clutches and Vents for 28 lbs of Stability

Celestron redesigned the mechanical systems of the EdgeHD to meet the demands of long-exposure imaging. The 28 lb aluminum tube is equipped with features to ensure stability and optical performance throughout an imaging session.

• Flexible Tension Clutches: To combat "mirror flop" or image shift during long exposures, flexible clutches hold the primary mirror in place after focusing. This keeps your target perfectly centered on the sensor without putting any performance-harming force on the mirror assembly.
• Integrated Cooling Vents: The rear cell features vents with 50-mesh filters that allow hot air to escape from behind the primary mirror. This helps the telescope reach thermal equilibrium with the ambient air faster, improving image stability and reducing tube currents.
• CGE Dovetail Bar: The included wide CGE-style dovetail provides a secure, rigid connection to any compatible equatorial mount, which is essential for supporting the 28 lb payload without flexure.

1593x Light Gathering Power with StarBright XLT Coatings

The 279.4mm (11") primary mirror gives this telescope an immense light-gathering capability—1593 times that of the unaided human eye. This aperture allows you to resolve stars down to a limiting magnitude of 14.7, revealing faint galaxies, globular clusters like the Hercules Cluster (M13), and delicate nebular structures that are invisible in smaller instruments.

To maximize the light that reaches your eyepiece or camera sensor, every optical surface is treated with Celestron’s premium StarBright XLT coatings. This multi-layer coating system dramatically increases transmission across the visual and photographic spectrum, resulting in brighter images and higher contrast, especially on faint deep-sky objects.

EdgeHD 11" vs. Standard C11: Why a Flat Field Matters for Imaging

While a standard Celestron 11" SCT is a legendary visual instrument and highly capable for planetary imaging, it projects its sharpest focus onto a curved plane. The EdgeHD 11" was designed specifically to solve this for astrophotography.

• Standard C11 Advantage: For a purely visual observer, the standard C11 offers nearly identical views at a lower price point. The human eye is very forgiving of field curvature.
• EdgeHD 11" Advantage: For an astrophotographer using a DSLR, mirrorless, or dedicated astronomy camera, the flat field is critical. On a standard SCT, stars at the edge of the frame will appear elongated or out of focus. The EdgeHD's aplanatic design corrects for this, ensuring pinpoint stars across the entire sensor and eliminating the need for a separate field flattener.