TS metal dew shield with acrylic Bahtinov mask for Seestar S50 from ZWO

TS-Optics metal dew shield with acrylic Bahtinov mask for the lens of the Seestar S50 from ZWO

The Bahtinov mask is named after its inventor Pavel Bahtinov. This focusing tool allows precise adjustment of your astro pictures to the focus plane of your telescope.

The Bahtinov mask is a simple but effective tool that can significantly improve the focusing of your telescope. In combination with the autofocus mode of the ZWO Seestar S50, it is a very easy and fast way to achieve razor-sharp deep-sky images:

Attach the mask to your telescope and slew the telescope to a bright star.

Ideally you want to use a star with medium brightness for focusing. It should neither be too dark nor too bright. The lines of the Bahtinov diffraction pattern have to be clearly visible.

The chosen star shouldn´t be positioned in the center of your live view, because most telescopes or lenses, although corrected, do not produce a plane field of view. We recommend to position the star in the outer third of your image. That way, you will achieve a better overall sharpness across your field of view.

Watch your selected star

If the image isn´t yet in focus, the central line of the Bahtinov pattern is shifted. this very line sits exactly inbetween the other two lines.

Now you have achieved optimal focus. Remove the mask from your telescope and you can start the exposure of your object.

Safety informations: PDF Download