The size of this mask is adapted for the lens hood of the popular 50mm – 180mm guide scope. This mask is based on my other designs and is only specially calculated for this guide scope, because I use this telescope myself.

The mask is calculated for the original focal length of 180mm with the classic Bahtinov factor of 200. This mask comes with a box by default

Unlike other Bahtinov mask on the market, the Bahtinov pattern of the mask has been calculated and adapted specifically for shorter focal lengths. This is often not the case with other masks, because many offers are actually designed for large telescopes with very large focal lengths, and are therefore too coarse.

Please note that the mask will sit with a slight play on the lens hood. However, this does not affect the function of the mask in any way. Please note that the material of the mask is heat-sensitive and starts deforming at 50˚C and hotter. The mask should be not left, for example, in the sun. Well, this should not be a problem in astrophotography