The ZWO Atmospheric Dispersion Corrector is used to reduce the effect of atmospheric dispersion on lunar and planetary images. By aligning two prisms made of H-K9L (BK7 equivalent) glass, you are able to significantly compensate for the optical distortions and aberrations that come with viewing the planets at lower elevations.
The ADC works best when paired with an optical system slower than f/10, such as a Schmidt-Cassegrain. For other setups, the use of a Barlow lens is recommended.
