|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
[fitsbits] problems with fits readers
At the behest of some individuals who read the aips output FITS files
closely, I made a change so that variables we keep in double precision internally are shown as double precision floats on output FITS headers. A user reports trouble with this: My problem is that it seems that neither the 'kvis' task in KARMA, or DS9 (the display and analysis programme used in conjunction with Chandra and XMM data analysis, see http://hea-www.harvard.edu/RD/ds9/), can handle correctly this new format. She did a diff on the headers from the current AIPS and the previous one and gets diff 03dec-version 04dec-version 16,17c16,17 BSCALE = 3.16551153040E-06 /REAL = TAPE * BSCALE + BZERO BZERO = 1.02674588561E-01 / --- BSCALE = 3.16551153040D-06 /REAL = TAPE * BSCALE + BZERO BZERO = 1.02674588561D-01 / 22,23c22,23 OBSRA = 2.50952791667E+02 /Antenna pointing RA OBSDEC = 1.72636944444E+01 /Antenna pointing DEC --- OBSRA = 2.50952791667D+02 /Antenna pointing RA OBSDEC = 1.72636944444D+01 /Antenna pointing DEC 27c27 CRVAL1 = 2.50952791667E+02 / --- CRVAL1 = 2.50952791667D+02 / 32c32 CRVAL2 = 1.72636944444E+01 / --- CRVAL2 = 1.72636944444D+01 / 37c37 CRVAL3 = 1.49399000000E+10 / --- CRVAL3 = 1.49399000000D+10 / 42c42 CRVAL4 = 1.00000000000E+00 / --- CRVAL4 = 1.00000000000D+00 / The FITS standard makes it clear that either format is acceptable and that neither the E nor the D STATE anything about precision (although they do carry an implication to knowledgable readers). I guess that I will have to roll back the change to AIPS in defense, but I would like to urge authors of FITS readers to check their code immediately to make sure that the D form is understood as well as the E form. This has been a part of the standard since day 1. Eric Greisen |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
[ANN] xmds-1.3-4 released! xmds solves complex problems simply and quickly | Paul Cochrane | Astronomy Misc | 0 | June 18th 04 07:06 AM |
[fitsbits] Start of the FITS MIME type Public Comment Period | William Pence | FITS | 8 | June 17th 04 06:08 AM |
[fitsbits] Happy Birthday, FITS! | Don Wells | FITS | 0 | March 28th 04 01:58 PM |
[fitsbits] (fwd) Windows Explorer Fits Viewer | Eddie Trimarchi | FITS | 0 | February 24th 04 06:46 PM |
[fitsbits] proposed FITS MIME types Internet Draft | Steve Allen | FITS | 0 | October 1st 03 05:49 AM |