where is back focus measured on my c8 edge

[iwols]

hi attached are 2 images but not quite sure where back focus is measured to on my c8 edge hd i know the ccd has 12,5mm  back focus and i am using point B can anyone confirm this thanks

 

Edited July 20, 2021 by iwols

[wxsatuser]

I believe it is C

Some way down this pdf, page 14 you will see the diagrams for the back focus.

https://s3.amazonaws.com/celestron-site-support-files/support_files/edgehd_whitepaper_final.pdf

[iwols]

9 hours ago, wxsatuser said:

I believe it is C

Some way down this pdf, page 14 you will see the diagrams for the back focus.

https://s3.amazonaws.com/celestron-site-support-files/support_files/edgehd_whitepaper_final.pdf

thanks