[BAA Comets] 2013UQ4 and mount tracking

[Peter Carson]

Hi All,
2013UQ4 is currently hurtling across the sky at breakneck speed. Last Sunday 6th I attempted to image it and was faced with the problem of how to "freeze" its motion. I opted for short exposures whilst the mount was endeavouring to track at the rate of the comet. My image was satisfactory and is in the comet image archive. For a bit of fun I created a movie of the individual frames and it can be seen on YouTube at http://www.youtube.com/watch?v=0wTyKBnG0pQ
What do others do when imaging fast moving comets? I have a Paramount which is capable of computing comet offsets from sidereal speed and tracking at the comets apparent speed and direction. However I've not found this to be perfect and the image still trails a little. I'm not sure if small errors exist in the ephemerides that TheSky software downloads from the minor planet centre or if its just that the mount is not capable of making the corrections perfectly. The mount tracks virtually perfectly at sidereal rate.
Any opinions or experiences?
Peter Carson