To: "Mitch Gordon" From: Amara Graps Subject: RE: PPS Peer review Cc: Amara.Graps@mpi-hd.mpg.de, SHOWALTER@ringside.arc.nasa.gov, nicholson@astrosun.astro.cornell.edu Evaluation of PDS PPS Data Archive by Amara Graps amara.graps@mpi-hd.mpg.de or amara@amara.com Heidelberg Cosmic Dust Group Max-Planck-Institut fŸr Kernphysik Heidelberg, Germany August 2002 The materials that I used to evaluate the CD is mostly contained in eleven Voyager notebooks (Six for Saturn dated June 1982 to April 1986, and five for Uranus dated January 1986 to February 1995) and one box of file folders. Since I have this material, and I've transported it with me these last 20 years, and the information is unique, I was compelled to use it. Well and good, but unfortunately the time to evaluate took longer than I thought, which I didn't know until I got into it, and began checking files (discovering that a large number of star calibrations were from me). I needed about a week to do this evaluation properly, and so now this is the result. --------------------------------------------------------------------- Question Mark, in December 1999, I wrote you notes regarding the Saturn star calibration data files, and I said in my letter that I would xerox pages from my notebooks for you. Did I do that? If not, do you still want it? I marked those (~20) pages, in the last week. For Near Future If you have questions or you need more information, which I have with me in my notebooks, I suggest asking before October 2002, because I will moving (Heidelberg->Rome) in November/December, and for some months my notebooks will be in storage and might not be accessible. --------------------------------------------------------------------- I have organized this evaluation in the following way, with the most emphasis on the data contents. Evaluation of: * Data Contents * details in separate attachment * Ease of Use * Given Tutorial (DOCUMENT/TUTORIAL.TXT) * Working through a past example * details in separate attachment ======================================================================= Evaluation of: ------------------------------------------------------------------- * Data Contents ------------------------------------------------------------------- Details are provided in the accompanying file: 'DetailedEvaluation.txt' SUMMARY: I think that the data on this disk is very well-organized, the directory structure is logical and I like the file naming convention because it is sensible and flexible. The data files which were formatted ASCII were easy to examine, extract and manipulate, however the binary formatted files proved to be a problem for me. I am not familiar with OAL, and I don't know if this is the normal way to extract files such as those binary files. If it is, then I am behind the times, and I should get up to speed on this approach. Instead, my attempt to read and extract some binary data was with an edited (for Unix) version of one of the supplementary programs provided in the 'Processing Software' portion of this disk, and, unfortunately, the read failed, and I don't know why. The labels for each of the data files was easy to understand, the 'Contents' file for each directory was useful, important (thank you) and also easy to understand. All of the processing steps illustrating the procedure from raw to 'final' product was clear. In several places where I could check the values of the data, I did. I found one discrepancy with the background values of the PS1CO1.TAB file. Since I thought the discrepancy might be due to differences between JPL and LASP in their PROCCS record numbering, to check that, I looked at a familiar region, the Encke Gap, in order to see if the background that you have stored is the proper one. It looked OK. I might be useful to mention somewhere that the PROCCS numbering changed ? (for viewers like me who used the old JPL numbering) I was very happy to see my favorite Saturn GS-3 mode stellar occultation (that part at the end of the main OC-1 mode) become part of the standard data archive. I didn't know that I was the only owner of that data, and seeing it described on this disk in the way that it was, was a pleasant surprise. I was disappointed to not see the any of the Saturn PPS 0.1 km 0.2 km 0.5 km resolution in ASCII form stored, even though I understand that these files could be very large, and it is likely expect the casual user of EASYDATA would not be interested in these high resolution files. I am not sure that the given geometry (range) information is accurate enough, since we we are given one range per record, and must interpolate between the 600 points in a record. I didn't see several 1981 star calibration files (that I thought existed) for the stars alpha Lyr, an alpha Cma, and an alpha Leo. I have provided more information if that would be useful. I have given more information for some files in the RAWDATA directory. In appendices to 'DetailedEvaluation, I have given Uranus PPS inferred PPS background and star values (publ in Graps et al., 1995), Uranus PPS published calibration and equivalent depths (to compare with above), more limit cycle information, a LWE memo of background at Uranus due to off-axis light, and notes for delta Sco star calibration raw counts as a function of electronics temperature. ------------------------------------------------------------------- * Ease of Use ------------------------------------------------------------------- SUMMARY: The binary data extraction was a problem for me, otherwise I give the highest marks for ease of use of this CD. * Given Tutorial (DOCUMENT/TUTORIAL.TXT) SUMMARY: I thought that this file would be an example "walk-through" to extract data, and it isn't. However, it is the most important file after 'AAREADME.TXT', and gives the most important information that I think a user needs. ------------------------------------------------------------------- * Working through a past example ------------------------------------------------------------------- Uranus ring data extraction and manipulation Task: Extract three cuts of the Epsilon ring, and compute the eccentricity of the outer edge of the ring using radiuses and longitudes. (roughly) Answer: eccentricity = 9.7 E-03 (Uranus Notebook #1,pg. 26 = eccentricity = 8.24622E-03, Elliot&Nicholson, _Planetary Rings_ = 7.94E-03) So then, same magnitude as 'right answer', but off, due to only working with very few significant digits, and lower resolution of the cuts used here, especially BPI. This can be improved using closer-to the highest resolution data. --------------------------------------------------------------------- Giving subjective evaluation numbers, from scale of 1 to 10: * Data Contents 9.5 (weighted most) * Ease of Use 9.0 * Given Tutorial (DOCUMENT/TUTORIAL.TXT) 7.0 * Working through a past example 9.0 --> Very Good Amara Graps -- ************************************************************************ Amara Graps, PhD | Max-Planck-Institut fuer Kernphysik Heidelberg Cosmic Dust Group | Saupfercheckweg 1 +49-6221-516-543 | 69117 Heidelberg, GERMANY Amara.Graps@mpi-hd.mpg.de * http://www.mpi-hd.mpg.de/dustgroup/~graps ************************************************************************ I'M SIGNIFICANT!...screamed the dust speck. -- Calvin Attachment converted: Data:WorkingPastEx.txt (TEXT/R*ch) (00044250) Attachment converted: Data:DetailedEvaluation.txt (TEXT/R*ch) (00044251)