Back focus and Explore 127 triplet

[GrampyG]

Hi

 

Anyone know what the back focus should be on Explore 127 triplet with flattener? Camera is a ZWO ASI 183mc

Thank you

G

[Adam J]

35 minutes ago, GrampyG said:

Hi

 

Anyone know what the back focus should be on Explore 127 triplet with flattener? Camera is a ZWO ASI 183mc

Thank you

G

It depends on the flattener and if it is operating at its optimum focal ratio / focal length. But 55mm is normally a good place to start. 

[CCD-Freak]

I use the AT2FF with my ES-127EDT and it needs 55mm spacing.  Works great.