The goal of the atmospheric dispersive corrector (ADC) is to compensate the dispersive impact of the earth atmosphere on the optical path of the light. The ADC should be especially used to compensate the loss of the contrast caused by the atmospheric dispersion.
All components have been designed to keep the full optical performance of the telescope.
Since the correction power of the ADC grows with his distance to the focus, distance tubes (about 40 – 100mm) should be inserted between ADC and the 1.25“ eyepiece holder when observing objects with zenith distances greater than 60°. For telescopes with F-numbers smaller then F10 a barlow lens should be used to reduce the beam divergence for minimizing the transversal color error.
In general, atmospheric dispersive correctors have two optical elements with dispersive power. Simple correctors have two single prisms which have to be turned contrary to find the optimal correction. These simple prisms introduce an asymmetry into the optical system which is responsible for a dramatic reduction of the image quality. This setup leads to a non-diffraction limited optical performance.

Consequently, we have designed our ADC to keep the diffraction limited performance by using plane plates as dispersive elements. These plan plates consists of two complementary prisms of different glasses. The glasses are selected to have the identical refraction index but different dispersions. Both interfaces have identical dove tails where the added T2 male and T2 female adapters fits in. This allows by more flexibility a fast change of the equipment.

TEC recommends this product be purchased with the ADC Adapter Set.