New Horizons at Io Options

[volcanopele]

Since the New Horizons Jupiter Encounter thread is already getting pretty long, I decided to create a thread dedicated to New Horizons' observations of the most interesting object in the solar system: Io. Info on upcoming observations comes from the jupiter_timeline_static.xls document john_s posted, and the preview images are from Celestia (note that each image is scaled so that the pixel scale is ~correct, and represents a smaller FOV than LORRI)

Today, February 24, New Horizons conducts three observations of Io with the LORRI camera as well some observations of Io's atmosphere with ALICE. These observations have the lowest phase angle for Io of the entire encounter. Phase angle continues to increase as NH approaches Jupiter and Io.


The first observation, ISunMon1, shows Io's sub-Jovian hemisphere (Clat=5.5 S, Clon=340.2 W) from a distance of 7,856,307 km. The resolution with LORRI would be 38.8 km/pixel. Pele is on the limb at lower right and Masubi is on the limb at lower left. Ra Patera is near center.


The second observation, ISunMon2, also shows Io's sub-Jovian hemisphere (Clat=5.5 S, Clon=15.1 W) from a distance of 7,575,510 km. The resolution with LORRI would be 37.5 km/pixel. The Tvashtar plume might be poking above the limb at upper left.


The third observation, ISunMon3, shows Io's leading hemisphere (Clat=6.0 S, Clon=84.7 W) from a distance of 6,627,459 km. The resolution with LORRI would be 32.8 km/pixel. The Zamama plume might be visible just above center on the left limb.

It only gets better from here. Not sure how NH downlink works, but there is a DSN window right after the last Io observation, hopefully at least one frame from each observation will be returned. Maybe they can do the Huffman window right around where Io is... Tomorrow contains four more observations of Io, highlighting Pele and an eclipse.

[ugordan]

@Bjorn:

Interestingly, I ran into the same kind of alignment problem when trying to fit a Solar System Simulator image of Europa to the image. I'm starting to think LORRI's pixels aren't perfectly square.

[Bjorn Jonsson]

@Bjorn:

Interestingly, I ran into the same kind of alignment problem when trying to fit a Solar System Simulator image of Europa to the image. I'm starting to think LORRI's pixels aren't perfectly square.

The Solar System Simulator uses a completely outdated airbrushed map of Europa based on Voyager data only. I wouldn't be surprised if it had large positional errors.

Here is what I get with my Europa map:



Matches the NH image almost perfectly (I will be posting a higher resolution version in a different thread since this is the Io thread). The big question is the Io map - I'm hoping for accurate Voyager Jupiter SPICE kernels to eventually show up so I can make a more accurate version someday...