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, and the text on the box. 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
• The mask can be ordered with or without the storage box with individual text inscribed on the cover
• I use a similar mask with my Esprit 100ED telescope.

Please select parameters according your needs:

• Tube 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 190mm. See my other offers for 50-100mm and for 200-250mm masks
• The focal length, if is more than 300mm. For focal length below 300mm, parameters for the focal length of 200mm will be used, since they work best
• 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 200 is used
• If you have chosen a variant with the storage box, you can add custom text which will be printed on the cover of the box. If you leave this field empty, the diameter and the focal length will be used. Please note that only one line is possible. One letter takes around 0.22 of the filter size, i.e 17 letters fit on a box for 77mm mask.

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 🙂