https://www.apm-tele...rrector-compact
after 9 month wait time of prduction, we got this increditable corrector now in stock
Product description
The Atmospheric Dispersion Corrector Professional from Gutekunst Optiksysteme
The Atmospheric Dispersion Corrector (ADC) corrects the effects on the telescope image caused by the atmospheric dispersion to maintain the full optical performance of the telescope. This holds true for photographic applications and especially for visual observing.
Why is correction of atmospheric dispersion important?
Atmospheric refraction describes the deviation of a lightray from a straight line as it passes through the atmosphere. Refraction depends on the wavelength of light: blue light is more affected than red one. As a consequence the blue part of an image is shifted to a higher position than the red one and a star appears as a tiny trail perpendicular to the horizon.
The greater the distance to the zenith is the larger the displacement is. Depending on the distance to the zenith the spread between blue and red starlight grows and exceeds 1 arcsec for zenith distances over 55° (35° above horizon). For comparison the resolution of an 8" telescope is about 0.5". For zenith distances greater 30° no diffration limited image can be achieved anymore, for a 24" telescopes this is already the case for 15°.
Features of the Gutekunst Optiksysteme ADC
the only corrector on the market which ensures diffraction limited images by maintaining the optical performance of the telescope.
complete restoration of the contrast
easy adjustment optimization of the dispersion correction because only one adjustment screw is need for adjustment (dispersion elements are automatically synchronized)
the object absolutely keeps its position during the adjustment
the 28mm aperture of the ADC compact is absolutely sufficient for visual observations with 1.25" eyepieces and with observations with binocular viewer.
Functional principle
The ADC has two pairs of prisms. Each prism pair is configured as a plan parallel plate with a crown glass and a flint glass. The glasses are selected to have identical refraction indices but different dispersions. The identical refraction index guarantees that the image doesn't move when the prisms are turned. When the prism pairs are turned by the same angle but in reverse directions the effect of compensation can be varied. In case the two prism have the same orientation the compensation effect is maximal. The compensation becomes zero in case the orientation of the prisms is exactly opposite (180°).
Simple correctors using two single prisms which have to be turned contra directionally to achieve the appropriate correction suffer from the 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.
shipping UPS is $ 70
