Third HSRC Release!, Includes map-projected calibrated images Options

[remcook]

great job! this is so cool

yay to more public releases

[DDAVIS]

great job! this is so cool

yay to more public releases

Where can I find NASAVIEW for Mac OSX? it's not in the usual JPL location.

Don

[djellison]

Here - http://pds.jpl.nasa.gov/tools/software_download.cfm - I think.

Doug

[jaywee]

Doug,
I just can't stress enough how magnificent the DD animations you made are. I wonder if ESA knows what they have (Have you shown them to Jim Bell?)

Anyway, as I said before - the archive is now available at http://pds-geosciences.wustl.edu/geodata/m...approjected-v1/ it's biggest advantage is easy accessibility of the thumbnail jpg images.

Oddly, eventhough the ESA page says it covers 1-1863, it ends at 1295. Have you found data from newer orbits in the PSA interface?

[djellison]

Yup - via the psa you can get to 1800andsomething

The browse JPG's are utterly perfect - they're exactly what was needed, and being able to just grab an orbits data instead of using the lengthy convoluted pain-in-the-backside PSA system is a big big BIG bonus - if you can catch up to 1863, it would be great.

Doug

[slinted]

I got a reply from the HRSC data processing manager, Dr. Thomas Roatsch, about some of the map-projected PDS/PSA tag issues, which seemed appropriate to share here.

As to the duplicate RADIANCE_OFFSET and RADIANCE_SCALING_FACTOR tags, the second ones are correct to the map projected images. For anyone particularly interested in the reflectance data, there is a necessary tag which is missing (REFLECTANCE_OFFSET). Dr. Roatsch has suggested to the PDS/PSA that they deliver a new version soon to fix both of these problems.

When considering the radiance information recoverable by applying the offset and scaling factors, a third tag becomes important as well. The radiance values are in units of Watts/m^2/sr, and is not spectral radiance (Watts/m^2/sr/nm). This means that the calibrated radiance values in the images are a summation across the whole bandwidth of the filter+ccd. This is important because bandwidths of the HRSC color filters differ significantly. The red filter is 48 nm wide, green is 88 nm wide, and blue is 76 nm wide. In other words, if one didn't take this into consideration, the green filter would appear almost twice as 'bright' as the red filter, since its radiance is considered across a spectrum twice as wide.

So, to recover spectral radiance from the HRSC map-projected images, one must apply the offset and scaling factors, then divide that value by the bandwidth of the filter.

[djellison]

Nice and simple then

Doug

[Malmer]

Dont forget to throw salt thrice over your left shoulder on a full moon night...

[Phil Stooke]

Here's a recent Phobos image from Mars Express.

Phil

[Guest_AlexBlackwell_*]

Here's a recent Phobos image from Mars Express.

I'm still looking for a good, perhaps even iconic, Phobos image for my avatar. The search continues...

[djellison]

My fav Phobos image...but I guess you're looking for something a bit better than that

D

[stevesliva]

Gotta have Stickney.

http://solarsystem.nasa.gov/planets/profil...ject=Mar_Phobos

[Phil Stooke]

Here's the most recent Deimos image in the PSA. It's a composite of two SR frames.

Phil

[djellison]

Here's one for you Phil,

Deimos has, to me at least, looked to be a much smoother almost 'softer' looking body than Phobos. Is that a symptom of the common images we see being of lower resolution, or an actual property difference between the two.

Doug

[Phil Stooke]

It's not a resolution effect. The best Viking images of Deimos have higher resolution that the best Viking images of Phobos. Deimos is smoother because it's almost completely covered by a thick debris layer. Peter Thomas (Cornell) has argued, and I agree, that the debris is ejecta from a crater with a diameter almost as large as Deimos's longest dimension, which is visible to us as the south polar "saddle" of Deimos. Most debris from a crater like that is ejected at very low velocity (forming the heaped-up rim of a lunar crater, plus lots of that never gets outside the crater at all) and coated Deimos at once. The rest was probably re-accreted from Mars orbit. Phobos lacks a "giant" crater of the same relative scale.

Phil