Here are some examples of focusing with a single mask on the C9.25 F10, native focal length of 2350m.
- At prime focus (2350mm).
- With TeleVue x2.5 PowerMate (5875mm).
- With TeleVue x4 PowerMate (9400mm).
The Bahtinov Mask was printed on two A4 overhead transparencies and then the gaps were cut out using a Stanley knife and steel rule, before gluing the mask to a camping mat foam ring.
Cheers
Dennis