Jupiter and Europa (did I capture surface detail on the Galilean Moon?)

Last night was cold and a little hazy, so I decided to do some planetary imaging. Jupiter was high in the sky at 6 pm Eastern when I began imaging. Haze can sometimes benefit planetary imaging but seeing did not seem to be particularly good. Capella was twinkling low on the horizon in unsteady air. I took a quick peek at Mars (also low on the horizon), but it was scintillating, and no detail was visible. However, conditions were better towards the zenith, and Jupiter’s image indicated average seeing conditions. I took some test frames with the 5 inch Mak and Skyraider SLP imager. I was puzzled by the low framerate (about 12 fps), when I noticed I was running at 2048 x 1536. I reduced the resolution to 1024 x 768 (my usual imaging resolution with this camera) and achieved about 48 fps.

The Jupiter image below if about 45% of 15,000 captured frames. The quality graph in AstroSurface was surprisingly flat, and the resulting image of Jupiter (wavelets in Registax) showed unexpected detail. Textures are visible in the north Polar Region and North Temperate Belt. Loops and eddies of gas can be see in the North Equatorial Belt, with swirling clouds in the Equatorial Zone. In the Southern hemisphere, one of the 3 white storms in the South Temperate Zone/Belt is visible (the white oval). Two moons are also visible in the image—Callisto (nearest Jupiter on the lower left) and Europa (further to the left and higher in the image). These moons appear irregular when zoomed, which is an indication of the quality of seeing when they were imaged.

Out of curiosity, I processed an image of Jupiter captured at the lower frame rate (750 of 1500 frames) and I noticed that the moons appeared round. I zoomed in on Europa and was surprised to see what looks like albedo detail. The image below shows this zoomed image. My quick, back of the envelope calculation, indicates that Europa’s angular diameter is 1.04 arcseconds. Given that the 5 inch scope can resolve about 0.9 arcseconds, that’s remarkable (unless it’s an illusion!). The color does seem to match that of Europa’s dark features.