Quote:
Originally Posted by Camelopardalis
The back focus of the sensor will be 17.5mm according to ZWO.
Your Esprit will present 55mm of back focus after the flattener.
Not sure how you’re getting such high numbers  |
It's 55mm from the back of the flattener body. The measurement above is taken from the glass (which is further back inside).
I have used my 2600MC on my Esprit, and just use 55mm from the back of both the 0.77x reducer/flattener and 1x flattener.