The SkyWatcher field flattener and reducer for the Evostar 72ED transforms your telescope into an astrograph perfect for widefield imaging. The 0.85x reduction factor will convert the focal ratio of your Evostar 72ED from f/5.8 to f/4.93 with the advantage of shortening the exposure time and extending the field of view. The native 420mm focal length is reduced down to 357mm. Refractors are affected by field curvature no matter what brand or diameter. This is not an issue for visual observations as eyepieces can partially compensate for these aberrations. On the contrary, when a refractor is used for astrophotography, a curved field will limit the corrected image circle and the stars on the border of the field will appear elongated. The field flattener and reducer can be screwed directly onto the focuser of the Evostar once the final ring on the focuser tube is removed. On the camera side, the reducer has a M48 male thread that makes this reducer suitable for the majority of camera adapters and T rings. Specifications Reducing factor 0.85 x Thread on the camera side Male M48 x 0.75 Thread on telescope side Female M56 x 1 Working distance 55 mm from the beginning of the M48 thread SKU SWA-ED72REDUCER
