This device is helpful for a successful approach to the images when shooting the sky with a Newtonian telescope.
The device causes an optical interference phenomenon that transforms the image point of a star in a picture of this type.
Adjusting the telescope's focuser is changed that image. This coincides with the focused image of the telescope.
There are web sites to design the mask Bahtinov for each telescope. This figure is for my telescope Hokenn 200/1000. The maximum diameter is equal to the diameter of the mirror.
To build the Bathinov I used cardboard from a folder, very hard, about 2 mm thick. I printed a 1:1 scale design and paste it into the carton.
Cutting the mask with a cutter.
Mask painted with matte black spray paint.
Wire supports, to keep the mask in place at the entrance of the telescope.
Bahtinov installed on the telescope.
Bahtinov view from the eyepiece holder.