Achromat and eta carina

[Terry B]

I decided last 2 nights ago to try using my guide scope with my 40D.
The moon had risen and useful imaging has ceased after taking pics of M46 (in another thread)
I took a single 300sec grab of eta carina neb. The moon washed out the image a bit and I didn't bother making a flat so have just used the flat from my main scope. This is far from ideal but did improve the vignetting reasonably well.
It has lots of purple halo around the bright stars. the stars on the edge of the field are far from round. This shows why I use my VC200L for imaging and the guidescope for guiding.

[Stephen65]

Thanks for posting that, aside from being a nice pic its a good illustration of the way an achro doesn't bring all the colours to a common focus!