[DJT (David)]

Hoping the collective brains here will help.

Am running an RC8 with an STL6303, using a 2.5 " moonlite focuser with adapter to the STL

I notice that when self guiding with the STL, the guide sensor is above the main sensor and with no flattener this means the guide stars have an element of coma

I am not sure if this impacts guiding when using centroid method in CCDOPS but suspect I should probably get a flattener at some point.

The astronomics dedicated 2" flattener has limited 55mm back focus and as I will want to put an MMOAG into the mix at some point for NB this wont be effective.

Wondering what other flattener options people are using with this sort of combo. I know Paul H has used a TAK flattener for a 130 frac of some sorts to good effect and I think the AP FF may suit but interested in other people's experiences ( including " get over it, it should'nt impact guiding.." )

Thanks