By the way since we are posting images I did a quick search on Eq6 and VC200L and found this chaps images. Little details provided but I think taken at 1.8m fl. Pretty good.
http://picasaweb.google.com/espeluznante33
Also found this on guiding at 2.5m focal length (yes I guess you could use a 10inch SCT at f10 - slow but certainly ok on a G11).
"
If reducing the guiding focal length seems counterintuitive, consider that
for a long focal length the limiting factor in the ST4's guiding is the
seeing limit. For example, at
2500mm each ST4 error unit is only 1/4 of an
arcsecond, and a seeing error of only 2.5 arcseconds will cause an "E"
indication. If the seeing is 3 arcseconds (fairly common) just the seeing
errors will cause continual "E" indications on both axes. In effect you are
trying to make the ST4 guide to a finer resolution than the seeing will
allow, which is not only useless but makes it harder for the ST4 to
recognize and respond to drive-generated errors. If you cut the guiding
focal length in half (with a reducer) then each error unit will be 0.5
arcseconds, still plenty of accuracy to achieve all the resolution the
seeing will allow, but without generating E's all the time."
I havent even tried to calculate it all out to check but my gut feeling is that while possible on a great night it might be hard at the best of times to guide at 2.5m fl. Couldnt find any examples of shots at 2.5m fl with an Eq6.
Cheers
David