I had a hard time finding some good ephemeris data for angular size so calculated it myself as follows:
[Theta doesn't show in BBCODE, I substituted &]
& = d / D, where & is the angular size, d is visual diameter and D is the distance to the object.
So using the WRONG units I get:
1.64AU distance to Ceres and 950km diameter of Ceres gives 0.798".
I hope to not have overexposed the object which would have caused bloat or bloom in the data. I stretched in post processing and resized to 200%