Stack check marked images

[AM]

I'm trying to stack comet 12P/Pons-Brooks using Emphemeris alignment with the latest version of ASTAP. I'm expecting the stars to be trailed and the stack to be on the comet but it just appears to stack on the stars. I have analysed the files and it knows the comet is there. I notice in the help notes for ASTAP it shows a button 'Stack check marked images'. I don't see that. I only see what I select on the stack method tab i.e. Average, Sigma clip average ...
Are my expectations too great or am I missing something that I need to do in the process?

[han.k]

Try manual alignment:
http://www.hnsky.org/astap#manual_alignment

or ephemeris alignment:
http://www.hnsky.org/astap#ephemeris_alignment

Since the images shift slowly, you have to use stack method Average.
If you can't get it running ask again.

Han

[AM]

Hi Han, thank you for the quick response. I did try the manual alignment and that did stack on the comet (stars trailed). I did try stack method average with the ephemeris option but it only appeared to stack on the stars. I will try again at the weekend.

[AM]

Thanks Hans, I tried it again. It worked perfectly. The ephemeris option stacked on the comet (stars trailed). I must have done something stupid the first time.