Congratulations Chris. I told you it is a nice lens
The other night I was playing around with spacing between the 70-200 lens and the QHY9 and the attached crops are 200% enlarged from a single 10 second test exposure of the SMC with the 70-200 2.8 non-IS set to 135mm and f2.8. One of the crops is NGC346 near the centre of the frame, and the other crop is towards the edge of the frame and is 47 Tucanae. No sharpening has been applied, just a strong logarithmic curve to bring up the background.
The image scale in these crops is 2.7 micron per pixel, or 4" arc secs pixel. Also the image is unfiltered, i.e no IR or UV block filter. The field of view of the whole image is 8 x 6 degrees. With this setup I can potentially image the entire night sky down to mag 15 in one night.
Terry