Is this a collimation issue?

[Geoff45 (Geoff)]

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

[gbeal]

Looks like it Geoff, but what does the lens cell look like, is there the ability to collimate? I mean some refractors have collimation screws, push/pull. Does the W/O have these?
If not, and another question, is there any means of collimation the Moonlite as well?
Nothing is impossible, just easier if the screws etc are there.
Gary

[Geoff45 (Geoff)]

Originally Posted by gbeal

Looks like it Geoff, but what does the lens cell look like, is there the ability to collimate? I mean some refractors have collimation screws, push/pull. Does the W/O have these?
If not, and another question, is there any means of collimation the Moonlite as well?
Nothing is impossible, just easier if the screws etc are there.
Gary

Haven't really looked at the ZS110, but I'd be surprised if the cell didn't have collimation screws I just thought it would be easier to pick someone's brain before going at it with screwdriver and spanners. The moonlite is collimatable and it's quite easy to check the collimation. Last time I checked it was OK.
Geoff

[multiweb (Marc)]

Before playing with the lens adjustment if any I'd check the focuser barrel and the squaring on the camera. Very unlikely the refactor is out of wack IMHO.