Originally posted by luftfluss
Thank you. It's not a particularly sharp combo, but there's just so much magnification that you can make something of it.
Size makes up for a lot of other shortcomings. I shot the moon with a MTO 1000mm f/10 with a a 2x converter a while back and I know I missed the focus because there was just so damn much shake on the tripod I was using which was not sized appropriately but even given that it is surprisingly detailed even if not sharp. Then lets add in the shake from the shot and I'm surprised it actually isn't worse. I should probably post it here too as 2000mm is above 300mm so why not:
2000mm f/20 shot of the moon (MTO 1000mm f/10 plus a 2x converter)
After creating a heavier sturdier tripod I did go and shoot jupiter at 2000mm with that lens and teleconverter. You can tell there is a great red spot and some strips but that is about it. You really need some big lenses to effectively image the planets.