Thanks
In the old film days I remember reading an article in Astronomy Magazine re deep sky astrophotography using hypersensitized high res. 2415 technical pan film. The writer said "Exposures should run 60 to 120 minutes under a dark sky" And thats without the benefit of immediately seeing the result, they would consider stacking of electronic images a luxury had it existed back then. I guess in those "old days" mounts would have to be extremely well polar aligned as even a slight error would see field rotation in a 120 minute exposure. Flexure must have been a difficult problem too.
RCW103 is faint but not impossibly faint, I was able to record it on my unmodded 300D without any filter. Eric, your rig will easily record it with the UHCS filter.
Scott