Duncan Munro from the D1scussions mailing list removed the IR blocking filter from his D50 and made it capable of Astrophotography. (http://www.sfu.ca/%7Edmunro/D50.html) But he also has astro images from an un-modified D50. How does he do it? I'm not sure myself! But here are his FAQs. (http://www.sfu.ca/%7Edmunro/DSLRnotes.html)

Here's one of the images from his site and his settings:
"M8 and M20. Unmodded D50. 699.3sec (Had to end exposure due to
twilight!) with a Nikkor 300 f4.5 (non-ED), ISO 800. Mode 3 with
no dark subtraction, black point set, colour balanced, and digitally
developed in IRIS."

http://www.sfu.ca/%7Edmunro/m8_m20_median_stack_asinh_thumb.jpg

Maybe, as it says, you have to shoot near twilight to get it exposed properly? And postprocessed to get it black. 11" exposure ... need to try this!