Dione Image Products Options

[Exploitcorporati...]

I'd think a way to approach it might be to use the SPICE kernels to get the instrument pointing as a function of time. It's possible to get the intersection of the camera boresight and the surface of the target (longitude, latitude) for any given time. That would give the lon/lat of the center of the image if the time that it was taken is known.

Unfortunately, the Cassini website doesn't give the time, just the date of each photo. But it does give the distance, so the spacecraft distance could be  used as a proxy for the time. There would be some error, but it might give the location within a degree.

Thank you. I'm curious as to the exact process used by imaging scientists to construct the spectacular (and accurate) mosaics that are publicly released. As is certainly obvious, my own "handlaid" composites exhibit gross distortions and misalignments, particularly with global views(see the squashed-looking south pole of Dione above). I would imagine that the lat/lon centerpoints could be positioned on a spherical model and the individual images reprojected accordingly as they are placed.

[volcanopele]

I use the SPICE kernels and information provided to us where we download the raws (similar interface to the PDS) to navigate each image in a program called ISIS (publically available from the USGS website). I refine those solutions using a combination of limb fits, tieing to a basemap, or tieing to adjacent images. once I am confident that the lat and lons in my images are accurate, I can use ISIS to reproject each image to the same geometry. For the Dione and Tethys mosaics released recently, those are orthographic projections centered on the same lat and lon and with the same pixel scale. For public release products, I just piece these together in Photoshop, just to speed things along. I can also mosaic the images in ISIS, but often that's a slower process.

[djellison]

I must admit - doing mosaics with a combo of PTGui and Photoshop is a lot easier now Photoshop has the warp tool, very powerfull and usefull

Doug

[Exploitcorporati...]

I use the SPICE kernels and information provided to us where we download the raws (similar interface to the PDS) to navigate each image in a program called ISIS (publically available from the USGS website).  I refine those solutions using a combination of limb fits, tieing to a basemap, or tieing to adjacent images.  once I am confident that the lat and lons in my images are accurate, I can use ISIS to reproject each image to the same geometry.  For the Dione and Tethys mosaics released recently, those are orthographic projections centered on the same lat and lon and with the same pixel scale.  For public release products, I just piece these together in Photoshop, just to speed things along.  I can also mosaic the images in ISIS, but often that's a slower process.

Thanks for the fascinating primer. I must admit that my learning curve with image assembly has been a comedy of errors. I made my first composite in Photoshop last January(a crescent Iapetus), but only figured out how to use the transform feature shortly after the Tethys flyby( I stumbled upon the warp tool by using an unintended key combo). I spent roughly three years doing cut-and-paste Galileo mosaics with a printer and a stack of 14x17 "magnetic" photo albums. The only people who were remotely interested in this bizzare hobby were a couple of clerks at the local USGS map store, where I would occasionaly drag one of those ridiculouly massive albums for them to pore over. Photoshop is a little less messy...

[scalbers]

Greetings,

I learned recently that there is a SPICE kernel interface for IDL on the naif.jpl.nasa.gov site. It could take me quite a while, yet this would be interesting to incorporate into my satellite mapping software. Then if I can set up a PDS/IMG interface I'd be all set...

BTW my latest Dione map update uses about as much of the released global (3x3) mosaic from the latest flyby as is reasonable. Now I can consider whether to include some of the regional imagery.

http://laps.fsl.noaa.gov/albers/sos/sos.html#DIONE

[Exploitcorporati...]

A few of the southern high-resolution frames(updated).
Background mosaic by NASA/JPL:

[dilo]

Beautiful view of Dione at low phase angle, taken from 1425000 Km on 23MAR2006/20:02:18 UTC
(clear background should be E ring...)

Original images:
luma channel: N00055875.jpg (clear filter)
chroma components: R=N00055873 (MT2), G=N00055874 (G), B=N00055873 (UV)

[Exploitcorporati...]

Here's an update on the D1 encounter last October, looking at the context for crescent and Saturnshine observations following closest approach. Thanks to Steve Albers for your astonishing maps and Chris Laurel for Celestia.


Amata mosaic:


Broad context:

High resolution frames:

Crescent mosaic (apologies to um3k for first attempt):

[Exploitcorporati...]

Full context:

[um3k]

Totally excellent, dude!

[Exploitcorporati...]

Just a heads-up for the rev after next...it looks as though Cassini will have an outstanding moderate-resolution view of pretty much the whole fracture system, as well as additional gap fill coverage to the north. This view of Dione on 24 July 2006 from Celestia's reference trajectory is from a distance of 260,000km, the field of view narrowed by a factor of two for visibility.

[angel1801]

Using the Solar System Simulator, I also have some good imaging opportunties for Dione:

November 20, 2006 (260,000km)

Good imaging of the moons south pole area as a crescent (like Iapetus on April 11, 2006!)

September 30, 2007 (78,000km)

The entire saturn facing hemisphere is sunlit!

[SigurRosFan]

Some compositions ...

Attached thumbnail(s)

 

[belleraphon1]

Has anyone noted tthe CASSINI CHARM presentation from 06/29/06?

"Magnetic Portraits of the Icy Satellites of Saturn"

Slide 27 to 32 and slide 45 conclude there is mass-loading at Dione so there may also be plume activity from this moon as well as Enceladus. The Dione mass-loading is an order of magnitude less than the Enceladus mass loading but the the team feels sure this is a REAL event.

Very cool and maybe we should be looking for some very faint plumes at Dione.

Also interesting that Dione and Enceladus both appear to have the greater density of any of the mid sized moons.

[belleraphon1]

Has anyone noted tthe CASSINI CHARM presentation from 06/29/06?

"Magnetic Portraits of the Icy Satellites of Saturn"

Slide 27 to 32 and slide 45 conclude there is mass-loading at Dione so there may also be plume activity from this moon as well as Enceladus. The Dione mass-loading is an order of magnitude less than the Enceladus mass loading but the the team feels sure this is a REAL event.

Very cool and maybe we should be looking for some very faint plumes at Dione.

Also interesting that Dione and Enceladus both appear to have the greater density of any of the mid sized moons.

Sorry all... the date on the presentation web site is 05/29/06...... I fumble fiingered ....

Also, these image mosaics are just awesome..... congrats to all.................