Here's 20x5min I did with a QHY8 and a Pentax SMC -M 100mm. I also did a small time lapse with a SONY NEX-5 and 200mm Pentax SMC-M lens which I'm still working on.
I did two stacks for the composite. One with the stars stacked and rejected the comet nucleus, the other with the comet nucleus and rejected the star trails. I then blended the two in Photoshop in two layers as lighten mode. It's the short story but it turned out to be very difficult to process because of gradients, trees, noise and this thing turned out to be fairly faint after all. Its tail anyway.
I have a high resolution version
here.
Hope you enjoy it - as always thanks for looking.