3 ms·

TIL Bahtinov Mask https://en.m.wikipedia.org/wiki/Bahtinov_mask https://en.m.wikipedia.org/wiki/Bahtinov_mask That’s a clever device for focusing a small scop

TIL Bahtinov Mask https://en.m.wikipedia.org/wiki/Bahtinov_mask https://en.m.wikipedia.org/wiki/Bahtinov_mask That’s a clever device for focusing a small scope.

bruma 1y ago
Not only a small one, it’s being used in real observatories for some quite big telescopes.
tambeb 1y ago
Also for focusing a digital camera for astrophotography.