Hi Andy,
I attach one more instance having trailed star in DEC, when I forgot to click "RA dithering only" I usually did.
Not sure if the exposure started when the dithering was still settling causing the problem.
This was the same night, I uninstalled PHD2.6.2 dev3 and reinstall PHD2.6.1.
I then clicked "RA dithering only" and the following frames are better.
FITS with trailed star with DEC dithering (0049 local time) : https://drive.google.com/open?id=0B_pmhCQ1-e6abnlLNHgydTRGc0k
PHD2_GuideLog_2016-09-17_004308.txt (123.4 KB)
PHD2_DebugLog_2016-09-17_004308.zip (534.6 KB)
sg_logfile_20160917004158.txt (357.9 KB)
David