CHARACTERISTICS OF THE ADC's  
 

Basis is an optical concept fulfilling following aspects:

- no reduction of the optical performances of the telescope

- not only removing of the fringes, but also completely restoration of the contrast.

- no image shift during the optimization
process for removing of the atmospheric dispersion

 
 

To achieve this, the dispersive elements of our ADC are designed as plan plates. Each plate consists of two complementary prism of different glass sorts glued together. The glasses have the same refraction index but different dispersion (Abbé number).
Additive an optional focus extender reduces the beam divergence for high speed optics (F-number smaller than 10). This minimizes the transversal color error especially when using a binocular viewer.
This effort is absolute necessary to maintain the full optical performance of the telescope system.

Simple correctors using 2 single prism which have to be turned contra directionally to achieve the appropriate correction have following disadvantages:

- The single prism system will shift considerable the image during the adjustment process for eliminating the atmospheric dispersion

- Further on the single prism system introduces an asymmetry into the optical system which results in a reduced optical performance. For this setup the diffraction limited performance of the telescope may no longer given.
With this system the dispersion can be corrected but with the price of reduced contrast.