Thanks Jeff and jjjnettie,
I did some more image capture on Sat night, but with some mods to the setup. I've extended the SA100 / CCD spacing and added a grism to the setup.
I'm now getting in the order of 8.9A/px, compared to the original 29A/px.
I went back and re-imaged a target from first night again. It's easy to see that the curve is not as "lumpy" as it was. The target was QY Carina. The slightly higher resolution is on file QY Car spectrum.png"
I've also included a spectrum of Eta Carina for good measure
cheers
