Actually, it's more than that as it includes the Filter Wheel too.
Here's a
link to IF's 'help' page (which took me a minute or two to unravel).
For some reason, the screenshot of the spreadsheet in my original post above is only displayed as a link rather than a picture. Suffice to say, you input:
- Scope Back Focus
- Camera Back Focus (Imager)
- Camera Back Focus (Guider)
- Focuser / Rotator Back Focus (fully retracted)
- Filter Wheel Back Focus
And then there's options to add back focus for any adaptors etc.
The Output data then provides details of what size spacer to add at the Scope Port, Imager Port and Guider Port. According to the data I've entered (based on specs for as many of the parts as I am able to gather), I have an 18.5mm spacer at the guider port, zero spacer at the imager port and -58.5 spacer at the scope port.
Not surprisingly, the last is in red with a warning that there is not enough back focus.
Hence my "does anyone know the scope side back focus of an ES102CF".
Unless it means the focal length perhaps (physically 565 from the front lens to the back of the scope??)
