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View Full Version here: : Focal plane of a zwo294mc using a 0.8reducer on a refractor


h0ughy
24-07-2023, 10:58 AM
As asked just need to confirm the back focus distance using a 0.8 reducer field flattner on a refractor. Can you just screw on a reducer directly onto the camera or do you need to set a distance?

oska
24-07-2023, 11:18 AM
All reducers and flatteners have a back focus distance of 55mm, except the ones that don't of course ;)

BuyoTheAstroCat
24-07-2023, 11:21 AM
you would need to have 55mm of backfocus (extension tubes) between the reducer and sensor.

using all the tubes included + the 6.5mm depth of the sensor in the camera housing, you will get 55mm

I use a sv405cc and that is what I need when I use my refractor with a reducer

h0ughy
24-07-2023, 12:15 PM
Thanks it's been a very long time since I have played with the scopes