Focal plane of a zwo294mc using a 0.8reducer on a refractor

[h0ughy (David)]

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 (John)]

All reducers and flatteners have a back focus distance of 55mm, except the ones that don't of course

[BuyoTheAstroCat]

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 (David)]

Thanks it's been a very long time since I have played with the scopes