Juno- Satellite Observations |
Juno- Satellite Observations |
Jun 16 2016, 07:23 PM
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Newbie Group: Members Posts: 2 Joined: 16-July 15 Member No.: 7601 |
I know this mission is not meant to study any Jovian satellites, but is Juno going to, by chance, pass near enough to any satellites (particularly small, not well imaged satellites) that it could take any useful pictures of them? (Or will it be possible to finagle the final de-orbit burn to send it past a satellite for this purpose?)
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Jul 24 2020, 05:16 PM
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Senior Member Group: Moderator Posts: 3233 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
Decided to start a new topic [I see there was already a topic from four years ago so I'm merging the two] for the discussion of Juno observations of the Galilean satellites, mostly because many of the best observations are by JIRAM and data from that instrument takes a few months to a year to show up in the PDS. There have been observations of moons via JunoCAM at lower resolution that have been useful, like observations of the Chalybes plume at Io.
The other day, the JIRAM team had a press release showing off their observations of Ganymede from PJ24: https://photojournal.jpl.nasa.gov/catalog/PIA23988 They don't say in the caption but I presume that the blue and green channels use L band data (3.455 µm) and the red channel uses M band imaging (4.78 µm). Let's take a look at the M band data since there are more surface feature contrast: at first glance that doesn't really look much like Ganymede does it? What if we do a quick invert of the brightness values? Okay, now it is starting to look like the Ganymede we know. The bright regions in the original image are the dark "Regios" (specifically, the one of the right in each image is Perrine Regio). The dark spots in the original image are bright at visible wavelengths and are the icy ray of relatively fresh impact craters. This invert method works because water ice absorbs light at 4.78 microns, so ice rich areas are dark while comparatively ice-poor regions are bright. So inverting the 4.78 micron images gives something that better resembles visible light images. For a comparison, here is a Cosmographia preview of the middle image: -------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
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