Thanks Paul and Derek. Yep. Massive is one word that fits these proms!
Here's a couple more... and a couple more one the way...
I think this disc is a better shot than the first one. This one was captured after IC Capture fell over (I think because the 'puter started downloading some updates, or something silly like that), so the scope may have had a bit more time to reach thermal equilibrium... focus/seeing certainly seemed sharper at the time, and I think that's reflected in the image.
Al.