Light from stars and planets is refracted by the air layer as it passes through the Earth's atmosphere. This refraction varies greatly with the wavelength of light; A type of effect called 'dispersion'. This dispersion can lead to irritating colored edges at the edges of the planetary disk. Therefore, the role of the atmosphere is essentially like the lens of a telescope with chromatic aberration. On the contrary, this means that if you use a highquality telescope without inherent chromatic aberration, you may even see color edges. The optical system of a telescope cannot correct atmospheric dispersion. This is where compact ADC instruments come in handy ADC is essentially composed of two rotatable prisms made of Bk7 glass. Prisms themselves produce a certain degree of chromatic aberration, which is opposite to atmospheric dispersion. Therefore, ADC corrected this stimulating effect. The relative position of the prism can be freely adjusted through a small slider. Features: ADC corrects the dispersion effect of the Earth's atmosphere. You will receive clearer images of planets and the moon. The atmospheric dispersion corrector is a revolution in observing and imaging objects. 3. Correct the false colors introduced by the Earth's atmosphere by using two highquality minimum 1/4 λ BK7 prisms. When used for planetary imaging, it significantly changes the clarity of the image, especially the brightness channel during LRGB imaging. 5. Adapt to simplicity through T2 thread and camera side 1.25inch tube and telescope side 1.25inch tube Specifications: 1. Brand: SVBONY 2. Model: SV199 3. Surface accuracy: 1/4 λ 4. Camera/eyepiece side: 1.25 "barrel+T2 male head 5. Telescope side: 1.25 "bucket 6. Optical aperture: 24mm available 7. Substrate: Bk7 8. Side: Blacking to improve contrast 9. Coatings: Anti reflective broadband (300nm-700nm) 10. Deviation angle: 4.5 ° 11. Required back focal length: 56.57mm 12. Net weight: 167g The package includes: 1 x SV199 1.25 "Atmospheric Dispersion Corrector 1 x manual