Table of contents :


Newtonian telescope

Dall Kirkham 200 mm F/4- F/15, Mewlon 210 F/2.9-F11.9 and Mewlon 250 F/3-F15

Gregory 250 mm F/3.2-F/28.4

Cassegrain 200 mm F/4-F/15 and Cassegrain 350 F4.9-F29.2

Ritchey-Chretien 500 mm f/3-8

Celestron "classic" and Edge-HD versions overview

Celestron 8 classic and Edge-HD

Celestron 14

Celestron 14 with optimized Schmidt plate position

Celestron 8 with optimized Schmidt plate position

Celestron 14 classic and Edge HD

CDK 355 mm F3 - F11.8

Barlow lenses



Celestron 8 Edge-HD and C8 classic :


OLSO model :

- The model of the C8 Edge-HD is from [1]. It is reported the specifications were provided by Celestron to the authors of [1].

Radius of diffraction limited flat field :

- 0.25° from 465 to 656 nm according to Celestron WhitePaper and [1].

Field curvature :

- the C8 Edge-HD is designed to provide a flat-field..

Sensitivity to backfocus :


Strehl ratio versus wavelength :

Simulations with the OSLO model shows that the C8 Edge-HD is diffraction limited on axis from about 485 nm to beyond 900 nm. The performance drops below 450 nm because of spherochromatism.

Focus versus wavelength (to be updated):




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