What are the optimum back focus distances for Celestron SCTs?
November 4, 2012
The back focus distances are as follows:
| SCT | Back focus distance from primary mirror baffle tube lock ring (in) |
| C5 | 5 in |
| C6 | 5 in |
| C8 | 5 in |
| C925 | 5.475 in |
| C11 | 5.475 in from 3 in-2 in Reducer Plate 5.975 in from 3 in Primary Mirror Baffle Tube Lock Ring |
| C14 | 5.475 in from 3 in-2 in Reducer Plate 5.975 in from 3 in Primary Mirror Baffle Tube Lock Ring |
Please see the EdgeHD FAQs for corresponding numbers for that optical design.
Updated 12/27/13
