[Jon (Jonathan)]

Hi Ken,

Here's the raw image of Altair. See what I mean about the curved lines?

I say "raw" but I should be precise. I opened the Canon CR2 file in photosgop via an importer, and saved it as a jpeg. Lord knows what's happening to the levels. I can do the same in MaximDL but then I have to manually adjust the screen stretch to bring out the detail.

I suspect that if it's not focus, the issue may be over-exposure. This is an ISO200 1 sec exposure. And/or the fact that the spectrum was at a 45 degree angle to the CCD, off centre, and taken with a focal reducer.

Cheers

Jonathan