Bahtinov Mask 75-300 Olympus Lens

thingiverse

A Bahtinov mask helps you focus stars for astrophotography. How to use it: 1. Find the brightest star in the sky (usually Polaris) -- Jupiter works great too! 2. Put the mask onto your lens and find the star in the viewfinder 3. set zoom and either manually focus to infinity or use autofocus to set focus 4. Take a shot and set the lens to manual focus immediately after if you had autofocus on 5. Make sure the center line is equally spaced between the angled ones and adjust accordingly until they are (see photos)