Very nice Paul
You've just jogged me into setting both of my Nikon F and EL film cameras up for a couple of star trail shots. I have the F sitting there right now with a 23mm at f5.6 and the EL is there with a 55mm at the same. I'll give them about 40 minutes too - the same as you and on 400ASA Fuji slide.
Time to develop all of these. I haven't done any in a while after getting the D40. At least I still use all of my lenses regularly
Cheers
Chris