Gary the single blue image was not in focus yet and then cloud came in. I used it anyway and that is why there is apparent CA.
The Skywatcher 150mm F5 achro is very well corrected for spherical aberration and with the Hutech FR gives an almost perfect flat field.
See here and below.
http://members.optusnet.com.au/~fmle...b_acr_01_6.jpg
Bert