As some of you may know, I now have a Tamron 70-200 f/2.8 (A001), with the matching 1.4x TC. I was trying it out a couple nights ago, and managed to capture Jupiter with four of its moons at 280mm, before our own moon rose. You can see the glow below it.

This is on my K-1, 280mm, F/2.8, 1/6s, ISO 12800

Nice. All four moons are very easy to see. But wouldn't that be 280mm at f/4, not f/2.8, given the teleconverter?

Regarding those moons, I was surprised a couple of nights ago to be able to see them in my K-3II's LCD using Live View at 10x magnification and a 18-135mm lens at 135mm. I guess I shouldn't have been considering the combined magnification.

Nice shot. Jupiter is bright enough and far enough out there that you can get good untracked shots of it even using a shutter speed of 200/(focal length) as it will closely approximate the movement of the stars across the sky so you can use the rules for shooting trail free stars when shooting it and its moons.

I remember the first time I shot it with a 300 and seeing the moons in live view. Get a big enough lens or one with enough light gathering ability and you can see them all in the view finder. The MTO 1000/10 I have in my possession will show the moons in the camera view finder and I would surprised if the SMC A* 400/2.8 didn't show them in the view finder but I haven't pointed it at Jupiter yet.

So many nice targets in the night sky, so many nights of bad weather spoiling the fun.

Saturn is right on Jupiter's trail as well. Two gas giants but the perpective difference is stunning in this shot.

Yep - I suspect it was f/4.