Back-Focus 101: How Filters Affect Back-Focus
14:34
Back-Focus 101: Celestron 8" EdgeHD SCT (no reducer)
11:32
Back Focus Explained - Astrophotography
18:45
Telescope Back Focus: The Ultimate Guide [TAIC Short]
8:37
Back Spacing for Field Flattener and Coma Corrector to Camera
13:01
William Optics Z61 Adjustable Field Flattener & Back Focus Distance
23:38
Pairing a ZWO ASI294MC with a Celestron SCT - Back Focus and OAG Setup
17:30
Triplet Refractor Apo Reducer/ Flattener - Attachment & Backfocus
11:53