Thanks for comments, Derek. I've been wondering (in general) whether RGB data would add significantly to these images. In the case of the Veil I'm skeptical, but for brighter objects that are mostly hydrogen it probably would.
The lens is stopped down to f/4, approximately. This is a tricky part of the adapter I made: There is a small piece that pushes the aperture actuator on the lens to the right place, but I set it by just visually comparing the aperture appearance with how it looks on my Nikon camera at f/4.
I wish that I had ordered the 31mm filters, but I didn't know about them at the time. However, vignetting with this lens is not very different from what I get with my 'scope. In both cases the optics are more complicated than a simple refractor (retro-focus design in the Tamron lens and focal reducer on the 'scope), so I don't really know how to apply the specification for minimum focal ratio - I just try it and see.
1. What f-stop did you use on the lens?
2. Do you use the less-obstructed 31mm filters that you can get for the QSI cameras, or were you able to flat-field any vignetting out with the regular filters?
Great image Greg! I liked the preview of it, but when I looked at the Full Size version, I was blown away with what I saw. Lovely focus, nice flat evenly-illuminated field, great colours, and a lot of detail.
Perhaps, after you have had your nap, you could aim to get some RGB data for the stars to take it from an "A+" image to an A++ . :-)
Comment by Greg Marshall on July 14, 2011 at 10:19pm
I made an adapter to attach Nikon F lenses to a camera with T threads. It was originally designed for a different camera, but just happens to work perfectly with my QSI583. That is, the thickness of the adapter puts the lens at just the right distance so that "infinity" focus is where it's marked on the lens.
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