Covering sparklers huh?...sounds fraught with danger
I do recon doing short exposures in deep sky imaging to combine with longer ones
is a little different though
...since the scope is tracking the object the whole scene was always in that same relative position all the time for the whole exposure, unchanged, the varying exposures just prevents the bright bits blowing out ie simply overcoming a shortfall in the detector. The final image represents spacially exactly what was in the scopes field of view throughout the exposure.
Thanks for the explanation Greg, cheers
Mike