Celestron 9.25 EdgeHD - Backfocus 101

In this video I discuss the 146mm back focus requirement for my telescope. Worth mentioning that there are many ways to get to your required back focus. I have a spreadsheet with back focus requirements when using different accessories. Equipment: Celestron 9.25 EHD - https://www.widescreen-centre.co.uk/c... Esatto + Arco 2" - https://www.widescreen-centre.co.uk/p... Large 3.3" SC tread - https://www.widescreen-centre.co.uk/p... M48 Camera Adapter - https://www.widescreen-centre.co.uk/p...