Baader Astro T-2 System Component Chart For over 30 years we have focused on the Astro T-2 thread system (M 42 x 0.75 mm); virtually every telescope manufacturer must offer this thread far ahead of the focal point of his instrument, such a universal T-ring (for DSLR cameras) can be connected. The only exceptions are (still) Russian equipment, there the thread diameter is the same, but the pitch is still 1mm per revolution - rather than 0.75mm! Therefore, we offer among other things a "Russians adapter". At only 7mm additional optical length it can allow so many Russian lenses or telescopes to be compatible with an international Astro T-2 (M 42 x 0.75mm) connector! For the sake of better recognition mostly are marked. See marking small 'a' or small 'i' in the respective indication! "a"; identifies an external thread (male); or, if Ø sign which a diameter, "i"; - a female is always (female) or - Ø character - an inner diameter. The Optical Length A small selection from the variety of products from the Baader Astro T-2 System The optical length describes the extension of the optical path caused by an adapter or accessory when inserted into the...
