While Cooling My Heels...

In the last post, I told the story of chasing down the (Dwarf) Planet Pluto from the back yard last weekend with the C14. Pluto wasn't in a great position for observing till a little later in the evening, so was looking for other projects to come to mind. Well, Saturn was sitting right there on the meridian staring down at me, so decided to do something with that. While playing peek-a-boo with clouds, the temps stayed warm, and the air muggy and I never got very good shots of Saturn itself, but with a few second exposure, the moons of Saturn were easily recorded. I ended up taking a series of exposures every 30 minutes for just over 3 hours starting at 8:20 (12 July, 0320 UT). I took a series of 2.5 second exposures, then for grins took some 15 second exposures as well. Turns out I used all of them, stacking them together for a single image for each of the 6 time stamps. Unfortunately, one of my 30m samples was completely clouded out...

Once all the images were taken, I wasn't sure what to do with them... Since Saturn is nearing the Milky way, immediately obvious was a number of stars as well as the planet and moons. I tried aligning on a star, but unfortunately, picked the moon I think is Iapetus, and got a weird stacked image. At left is shown a proper stack referenced to an actual star. Saturn is, of course, the way-overexposed oval in the center. While it is obvious that the planets move slowly across the sky, I was surprised to see how much Saturn and moons moved during the 3 hour observation period! Each of the moons appear as a series of points as their motion carries them along relative to the stars...

Again, how to display them and show the dynamics of the system... After finding the gif software for the last Pluto post (a free download called PhotoScape), that seemed to be a natural. I first made a sequence as above, aligning all the frames on the star at the lower edge below Titan. I decided to use the images at full camera resolution, just showing the inner 6 moons. This first gif is shown at left.

After showing it to a couple friends for feedback, one suggested centering on Saturn, since that is what the moons were circling. He thought the motion of planet and moons relative to the stars was a distraction. So I worked on that tonight. Unfortunately, most stacking routines won't automatically register on an extended object like an overexposed image of Saturn, and I wasn't smart enough to do it manually. Fortunately Nebulosity has an automatic non-stellar alignment, and it worked ok, but not great. It is shown at right with a little jerkiness, with a couple labeled frames included for identification... I liked the effect, but would like some better images, perhaps on a future cooler night.

Anyway, another fun project - am already looking forward to next June during an opposition night when the coverage could be at least doubled or more.