From: "Shawn M Brooks"
Date: April 10, 2007 12:45:28 AM PDT
To: "Mitch Gordon"
Cc: "Mark Showalter"
Subject: A Few Comments on the PDS CIRS Rings Volume

Mitch,

     My apologies for the last second comments.  It's been a
little crazy for me lately and, unfortunately, I don't get paid
to do this sorta stuff anymore (not that I ever really did, I
guess ...).

     These comments are far from exhaustive.  I really only had
time to take a cursory look at the data set.  And, because of
time limitations and my computer set up, I wasn't able to play
with the data as I would have liked.  But, here's a brief,
bulleted list of comments and questions.  I can expound upon them
at the telecon.

 - As with most every PDS Rings Node product I've reviewed, the
PDS Cassini CIRS data set is well organized with a consistent,
easily understood hierarchical structure.  There is a wealth of
detail to be found among this archive (e.g. description of the
CIRS instrument, noise and spike discussion).  However, it seems
that the hierarchical nature of the archive leads to a lot of
unnecessary repetition.  For example, is it really necessary to
have identical descriptions of the volume in each subdirectory?

 - Would it be possible to include a file containing a list of
observations and the start and end times of those observations? 
The data are organized using a YY-MM-DD format, whereas I am used
to thinking of them in a YY-DOY format.  The inclusion of such a
file would help a user such as myself navigate this data volume.

 - Exactly how were variable length records turned into fixed
length records?  (Dumb question, I know, but I can't quite tell.)
 Was it something as simple as segregating spectra by their
record length?

 - Over what wavenumber range have the integrated radiances
described in the ISPM_ASCII.FMT file been taken?  I know that,
particularly in the case of FP1 data, noise at the long
wavenumber end of the spectra degrade the utility of this
parameter.  If the size of this data volume is a problem, I might
suggest cutting this parameter.

 - I personally dislike the YY format of the file names,
particularly the YY+50 for the re-formatted data.  I realize,
however, that this may be necessary due to PDS conventions.  I
just thought I'd point it out, though.

 - Just what are the origins of Vanilla?  I thought that it had
something to do with previous Mars missions, but the discussion
in TUTORIAL.TXT implies to me that it was created for Cassini.

 - It seems that geometry data referring to Saturn's rings are
referenced with the number 699, the NAIF ID for Saturn.  That
this is so should be explicitly mentioned.  Maybe it is, but I
couldn't find it.

     As I said, I couldn't actually plot up the data.  But, I
know that some of the observations have had problems where the
data files were calibrated inconsistently.  This showed up in our
analysis as a sudden jump in ring temperature.  I remember this
particularly for a SHAD or a SCAN earlier in the mission (it
would be included withthis release of the CIRS data).  I don't
know if this problem has been solved, but I should probably take
the time to look for it in this data set and report back if I
find it.

     And, that's about it.  Sorry for the brevity.  I can get
back to you with more thorough comments later, if you wish.  I'm
about to head off to bed.  Talk to y'all in the morning!

                                                      --- Shawn