went out again tonight and managed to grab this beauty. it's a 100% crop with only a sharpen applied via picasa.
for this shot, i used your aperture trick and took a range of shots at different apertures. i find the autofocus does a better job with a smaller aperture, dunno why, but it seemed to work a treat tonight! i also threw on the lens hood, and i didn't have to contend with really thin cloud either!
Canon 400D + Sigma f/4-5.6 70-300mm DG Macro
ISO: 400
Shutter: 1/1000s
Focal Length: 263mm (426mm equiv.)
Aperture: f/8.0