Celestron Schmidt-Cassegrain telescope SC 203/2032 EdgeHD 800 OTA

The Celestron EdgeHD telescope.

EdgeHD is the name for Celestron’s “aplanatic Schmidt Cassegrain telescope”. After over 50 years of success, Celestron has revolutionised the classic Schmidt Cassegrain telescope.

EdgeHD telescopes (“Edge High Definition") are true astrographs. This optical system delivers distortion-free, sharp images right to the edge of the visual field. This means that not only the coma without the optical axis is corrected, as is the case in currently available “coma-free” lens designs, but also field curvature.

Lots of optical systems are advertised as “astrographs”.

As desired, they display stars with pin-sharp clarity, but along a curved image plane. Photographing this using a camera results in a noticeable image field curvature which rises towards the edge of the image field, resulting in increasing star size and aberrations with larger sensors. The stars at the edge expand into small rings (“doughnuts”). As well as the coma, the Celestron Edge HD telescopes correct field curvature right up to the edge of the image. This also significantly improves resolution and magnitude limits in comparison to rival optical systems.

The XLT multi-coating helps to give the EdgeHD scopes a significant performance boost compared to similar systems on the market.

The Edge HD telescopes’ mechanisms and lens tube have been fully overhauled:

• mirror clamps hold the primary mirror securely in any desired position without putting pressure on the optical elements. The image is stable, even during long exposure times.
• Air vents behind the primary mirror provide fast air exchange so that the lens cools amazingly quickly. Thanks to an air filter system, dust is prevented from entering the lens tube.

This variant of the OTA comes equipped with a 3" Losmandy rail - suitable, for example, for use with the Celestron CGEM mount.

Specification

Optics

Type                                                                    Reflector

Type of build                                                      EdgeHD-Cassegrain

Aperture (mm)                                                   203

Focal length (mm)                                             2032

Aperture ratio (f/)                                              10

Resolving capacity                                             0,57

Light gathering capacity                                    841

Max. useful magnification                                 406

Tube weight (kg)                                               6,35

Tube construction                                             Full tube

Focuser

Type of build                                                      SC thread

Connection (to eyepiece) (inch)                         1,25"

Mount

Mounting type                                                  no mount

Type of build                                                      OTA

Included accessories

1.25'' eyepieces                                                 Plössl 40mm

Finder scope                                                      9x50

Deviating optics                                                1.25", 90° star diagonal

Prism rail                                                            Losmandy-Style

General

Series                                                                  OTA

Area of application

Astrophotography                                               yes

Moon & Planets                                                  yes

Nebulae & galaxies                                             yes

Sun                                                                      no 

Recommended for

Beginners                                                            no

Advanced                                                            yes

Observatories                                                      no