|
The FF I'm using is the TOA67 Flattener, I have been advised it has a back focus distance of 106.2 mm. I have made up a sliding adapter which gives me +\- 10mm or so either side of that figure. This is without my filterwheel because it adds to much length to the system.
I read the TOA67 Flattener has a tolerance of 2mm?
The QHY9's sensor distance is 15mm, 17mm, or 16.3mm depending on were you get your info from I found. Not sure if it's to the body surface or the flange which is about .5mm future away! The 16.3mm measurement is apparently taking into account the refractive index of the CCD chamber glass and the glass on the CCD surface, to the actual silicon layer.
I am still unsure about the colour filters affecting my measurement. I haven't been able to find out how thick QHY's colour filters are by googling, or on the forum. Might have to ask them directly. If the FF does have a tolerance of 2mm perhaps the filters won't make a difference???
I will try what you suggested Peter, find a star field and just experiment!
Erik
|