After quite a long trial-and-error (8-10 different masks with different patterns and manufacturing methods) and researching what fits best, I came up with design of a Bahtinov mask that meets all the characteristics so that I finally don’t have to worry about focusing anymore.

This mask can be used with many telescopes and refractors.

What are the special characteristics of these mask?

• The Bahtinov pattern will calculated according to your parameters: diameter, focal length. Most other masks on the market are actually designed for larger telescopes with very long focal length and so have a much too coarse pattern
• I use a similar mask with my TS RC8 telescope.

Please select parameters according your needs:

• Tube inside diameter in mm where the mask will be placed. Note that a certain tolerance is added to this size so that the mask will fit with certainty. The maximum diameter is 250mm. See my other offers for 50-100mm and for 100-190mm masks.
• The focal length
• Optionally and if you are familiar with this, or just want to try it out, select an individual Bahtinov factor. By default, the factor of 150 is used
• Custom text to put on the mask. By default, the diameter and the focal length will be used

Due to its large size, this mask is not available with a box.

Please note that the material of the mask is heat-sensitive and starts deforming at 50˚C and hotter. Thus, the mask should be not left in the sun, for example. At night, however, this should not be a problem 🙂