From owner-fitsbits@marmoset.cv.nrao.edu Thu Aug 7 12:11 EDT 1997 Message-Id: <199708071608.MAA14577@fits.cv.nrao.edu> From: Don Wells Sender: owner-fitsbits@marmoset.cv.nrao.edu To: iaufwg@fits.cv.nrao.edu, fitsbits@fits.cv.nrao.edu Subject: Successful demonstration of DATExxxx interoperability Date: Thu, 7 Aug 1997 12:08:15 -0400 (EDT) Dear friends of FITS (especially the IAU FITS Working Group), I am pleased to report that the necessary interoperability demonstration of the proposed DATExxxx agreement has been achieved. Preben Grosbol used a version of MIDAS to read the FITS test file which Eric Greisen had produced with a version of AIPS. Preben then ordered MIDAS to write the data out as another FITS file, which Eric has read successfully with AIPS. The dates are consistent in the two systems and two files (see below). The original test file produced by AIPS is ftp://fits.cv.nrao.edu/fits/data/samples/year-2000/newdate.fits.gz and the version of this file produced by MIDAS is ftp://fits.cv.nrao.edu/fits/data/samples/year-2000/y2000m1.fits.gz Header listings are in files "newdate.lst" and "y2000m1.list" in the same directory. The command "grep 'DATE' newdate.lst" produces DATE-OBS= '1979-09-19' /OBSERVATION START DATE DD/MM/YY DATE-MAP= '1992-09-18' /DATE OF LAST PROCESSING DD/MM/YY HISTORY PUTHEAD DATE-OBS =' ' / old HISTORY PUTHEAD DATE-OBS ='19790919' / new DATE = '1997-07-25' / File written on yyyy-mm-dd and command "grep 'DATE' y2000m1.lst" produces DATE = '1997-07-29T14:37:32' / Date of writting: DD/MM/YY DATE-OBS= '1979-09-19' / MIDAS desc.: O_TIME(1) HISTORY PUTHEAD DATE-OBS =' ' / old HISTORY PUTHEAD DATE-OBS ='19790919' / new DATE-MAP= '1992-09-18' / DATE OF LAST PROCESSING DD/MM/YY Note that MIDAS appended a time string to the DATE value. I recommend that all FITS writing code use the new time string capability with DATE in this manner, even if they don't use it with DATE-OBS etc., because it produces a useful unique time-tag in each FITS file. Preben supplied a second FITS test file, a nice galaxy image, at ftp://fits.cv.nrao.edu/fits/data/samples/year-2000/y2000m2.fits.gz The command "grep 'DATE' y2000m2.lst" produces DATE = '1997-07-29T15:02:58' / Date of writting: DD/MM/YY DATE-OBS= '1993-05-17' / MIDAS desc.: O_TIME(1) I encourage all of you to test the FITS readers of your datasystems with these files, and to report the results to the FITS community. I will be pleased to add DATExxxx test files produced by the FITS writers of other datasystems to this directory. Regards, Don Wells (Chair, IAU FITS Working Group) -- Donald C. Wells Associate Scientist dwells@nrao.edu http://fits.cv.nrao.edu/~dwells National Radio Astronomy Observatory +1-804-296-0277 520 Edgemont Road, Charlottesville, Virginia 22903-2475 USA