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Stardust Raw Images Of Wild 2
elakdawalla
post Jan 10 2006, 09:40 PM
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I just created an index page to the 72 raw images captured by Stardust of Wild 2 on the day of the encounter (downloading the original images from the PDS in a jiffy with that wGet software -- what a great innovation):

Stardust Encounter with Wild 2: Raw Image Catalog

As I was working with it to compose more stuff about Wild 2 for our website I realized that all those raw images are flipped left-to-right. Compare this one:

to the maps from the Brownlee et al Science publication:

I am assuming that these (as well as the ones in the Sekanina et al paper that follows it) have the correct orientation.

And yet the most famous picture of Wild 2, the one used for the cover of Science in fact, has not been flipped.


This is really key (and confusing) in part because of the team's names for those big, flat-floored depressions -- Left and Right Foot. Which one's left and which one's right depends on whether the images have been flipped or not!

I'm sure this is not news to people who paid more attention to Stardust when the encounter happened than I did. Does anybody here know anything about why the images in the PDS are flipped?

--Emily


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djellison
post Jan 10 2006, 09:59 PM
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Didnt the Stardust camera employ a mirror to flip the view? Might have had something to do with it. Either they didnt compensate for it when did the press imagery and have for the raw release, or vice-versa.

Looking at this - http://www.nasa.gov/mov/139826main_stardust-trajectory.mov - the spacecraft was overtaken by the comet in a deep-impact style. So, if you were a human spacecraft, with your head 'up' (i.e. standing in the same orientation as one would stood on the north pole of earth) - the comet would have travelled from right to left.

Thus - the early images should have the shadowed side of the comet on the left, and the last images the shadow on the right - or to put it another way - the comet should start with the lighting from the right, and finish with it being lit from the left.

i.e. the sequence as it sits on that (very very good) website is geometrically wrong.

Now - the problem is - you could take an image that appears to be the wrong way round, and either rotate 180 degrees, or flip horez, and have different results. Now - if the PDS released data is as it came from the CCD - then it will need to be flipped left to right.

I think smile.gif

Much kudos on the website - did you do that pulling-of-data-from-PDS headers all by hand ohmy.gif


Doug
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elakdawalla
post Jan 10 2006, 10:07 PM
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QUOTE (djellison @ Jan 10 2006, 01:59 PM)
Much kudos on the website - did you do that pulling-of-data-from-PDS headers all by hand ohmy.gif
*

Nope, it all came from the oh-so-wonderful INDEX.TAB file, which can always be found in the INDEX folder in every disk from the PDS. The file consists of tons of columns of data, the significance of which you can discover from inspection of the INDEX.LBL file in the same folder. For grins, I've attached my translation of the Stardust Wild 2 disk's INDEX.LBL file.

I open the INDEX.TAB file in Excel, mess around with it, move columns, play with number formatting, concatenate things together into strings, bring that into Word, split things into paragraphs (Find and Replace is my friend), and then copy and paste the captions I've built into my database-driven image library to make the Web page. Easy as pie smile.gif

--Emily
Attached File(s)
Attached File  stardust_navcam_wild2_index.lbl.txt ( 16.29K ) Number of downloads: 161
 


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