Hi Al, your going against the digital tide there mate - good on ya for daring to deviate from the norm
as for scanning 35mm negatives/slides your up against it - I am a scanned (glossy) colour print kind of guy myself
(very rare!) I believe the observation that prints have a better dynamic range than scanned negatives/slides - despite all the cons with doing it that way - to me personally negative/slide scans look a bit soft in focus. Unless you are scanning medium and large format negs/slides - 4x5 - 6x7 I personally wouldnt bother. The best stuff is from 6x7 format IMO. But i can appreciate the reasons people do it that way. Here is two sites dedicated to film astrophotography (well mostly) first the venerable and ancient APML
http://seds.org/mailman/listinfo/astro-photo (the big daddy of them all and the oldest on the net - i think) and
http://groups.yahoo.com/group/Filmastrophotographers/ - they are extremely helpful people - not many 35mm people tho
Kearn