Bahtinov mask for tubus with outer diameter 368 to 444 mm | Astrozap

Even with a very large telescope, you want to make sure you are sharp before you start. This Bahtinov mask makes that exactly clear with three light spikes around a bright star.

You place the mask in front of the opening and turn the focus ring until the middle spike falls neatly in the middle between the other two. It fits a tube or mist cap with an outer diameter of 368 to 444 mm, a size that you mainly see with large Dobson telescopes and other large viewers.

First measure the outside of the front of your tube; with a professional Dobson, measure the upper ring. Remove the mask as soon as you are focused, because it blocks some of the light and gives spikes in your image. Learn more about setting up your telescope in adjust telescope.

If your tube is slightly thinner, it will fit. the mask for 292 to 368 mm possibly better.