The attached composite shows enlargements from the corner of a 15mm x 15mm chip (QSI 540 wsg) taken with a William Optics ZS110. The stars in the corners show elongation away from the centre, which could be put down to field curvature. However, the corners are not equally elongated. The bottom right is almost OK. This suggests that the focal plane is not square onto the sensor, which could be caused by camera tilt or miscollimation. I am inclined to think it is miscollimation, since the I have a Moonlight focuser with all T thread attachments and I had a similar effect using a DSLR with a different focuser and connecting tubes.
So there are two questions:
- Is this likely to be collimation error?
- Has anyone had experience in collimating the ZS110?
Geoff