[Paul Haese]

This is a mystery to me. I am now using the OAG in the QSI. I have the flattener around 140mm from the CCD. That I am sure is incorrect. Tak owners might know that the metal back distance is 107mm, I thought it meant 107mm from the metal of the flattener to the back of the extension from the camera. However, is the metal back distance from the flattener face to the CCD? If so I am going to need an adapter from the QSI body to the flattener.

So the problem as I see it I have round stars through the central area of the image but flaring stars to greater degrees in the corners. The curvature on CCD inspector says that it is around 39-44%. With the stars in the corners, some stars are round and others are elongated. Why is this so? I am thinking some smaller stars cover the problem by have bloat, while the brighter ones just show the elongation.

Is this a flattener problem or is there more going on? Flexure should not be a problem. Collimation is around 7.1" depending on seeing conditions; but this is an accumulation where some images had 3.9" and some 4" etc. I have not seen any flop like I was getting before borrowing some extensions from a mate here that bought another 8" RC.

Anyone with suggestions?