Has anyone ever observed Ceres as a disk visually? I know it can reach an angular diameter of 0.85", which is comparable to Io (1") and Europa (0.86"), and these can be seen as disks with an 8" scope in good seeing at high enough power.
I'm thinking that with a 10-12" telescope at very high power under excellent seeing, it would be possible to see Ceres as a tiny disk when at maxmimum angular diameter.
It's a bit of a tough ask, but I have split .5 arc second doubles with larger instruments which suggests that even Vesta may be possible with a decent instrument and great seeing. 10"should be plenty large enough for the Ceres job.
Come opposition in December, I'll certainly try it, it's something that's been on my list. Unfortunately it'll be poorly positioned for us on the Taurus/Gemini border so will be battling seeing at low elevation.
I think any night good enough to see Europa as a reasonably 'clean' disk should be good enough for Ceres.
Come opposition in December, I'll certainly try it, it's something that's been on my list. Unfortunately it'll be poorly positioned for us on the Taurus/Gemini border so will be battling seeing at low elevation. 
