[Rob_K]

Originally Posted by Outbackmanyep

Hi Mitchell!
The streaks are background stars which have "trailed" due to the proper motion of the comet against the background stars.
Comets moves relatively quickly in short periods of time, so if your subject was to photograph the stars the comet would trail, but the comet being the subject in the stacking process you align the comet instead, giving rise to the trailed image of the stars in the background.

Hope this helps!
Nice image Gary!

Cheers!

I think Mitchell means the faint diagonal line over the top of the comet, right across the frame - probably a satellite trail on one of the subs.

Cheers -