True... though in the case of the moon-earth system, the barycenter is about 1000 miles inside the Earth. And all the other planets, meteors, comets, and dust in the rest of the solar system are perturbing our orbit too. Even the surrounding stars and galaxies have tiny effects on orbits if you can measure them precisely enoigh.

Neat fact, the Sun-Jupiter barycenter is outside the surface of the sun. So, the solar system actually orbits empty space :)

That could actually be a stable configuration... the two moons would orbit their barycenter, and that barycenter would orbit the planet. It wouldnt last forever but easily hundreds of thousands of years, like the rings of Saturn.

I still have a lot to learn, but I like to go out right at sunset and get my telescope set up. Start getting the computerized mount set up and aligned to the first two stars I see while there is still enough daylight not to trip over it. It also gives the optics a chance to acclimate to the weather. Then I use the time waiting for it to get truly dark to pick my target and fine tune the alignment with 30 second single exposures (if I can see the target at all). I'm on a budget system though (alt-az computerized mount with webcam-style eyepiece camera and laptop). If you have a more permanent setup, a more capable mount, or otherwise faster setup, you may not need as much prep time as me.

Awesome work! Im trying to do the same sub-$1000 astrophotography with much less success. I spent half on the telescope (Celestron Nexstar SLT 130) hoping I could use my cell phone for imaging but looks like I should have saved more for the camera. Didnt work out so well so far but I think an inexpensive eyepiece camera and stacking will solve the remaining issues. Keep it up... this hobby doesnt have to break the bank to open up the cosmos.