The Moon, the Jovian (jupiter) system, and the Uranus system, all on the same scale (all photographed prime focus through an 11in f6.3 SCT) aug 10th 2011.
The moon, Jupiter and moons, and Uranus and moons, all to scale. Click to enlarge.
It’s all part of a larger project I’ve been working on of trying to get time-lapse of various extra-terrestrial bodies.
The real problem is the Earth is just spinning too bloody fast! Damn, there’s a reason why all those new telescopes are going out there in the Legrange points!
Initially I was having all sorts of trouble tracking the moon! Hmm that just shouldn’t be, it tracks everything else in the sky just fine. Then of course, the obvious dawns on me:- it’s tracking the stars and not the moon! The moon goes around the sky an extra time every 28 days! Thats about 12 degrees a day, or half a degree an hour! Given that the moons only about half a degree in diameter, no wonder it kept drifting out of the field! Okay, so I got intermediate time-lapse of the moon, that shows the project is possible. A failure, sure, but a very instructive failure.
After the moon I took some caps of Jupiter and moons, and Uranus and moons, great for putting them all into perspective. Then it dawns on me, that it might be possible to do a timelapse of Uranus’s moons too, that’d be really cool. So I set up the scope to take pictures every 5 minutes. The results weren’t that impressive (well it only ran for a few hours before dawn), but more interestingly is that you can actually see uranus move against the background stars over this period. It really threw me, because I was trying to line up the background stars, and it just wasn’t possible, then the obvious came to mind. Duhh, Uranus is moving! So yeah, inadvertently I’ve now found that you can watch the planets move in real time! Probably works best on the faint ones, like Uranus, as you can see more background stars!.
The stars in the background are fixed. The two picture of Uranus are taken a few hours apart, and while the moons (relatively close to the planet) don't move much, the planet conspicuously moves against the background stars!) (click to enlarge)
Thunderf00t 