From landsman at stars.gsfc.nasa.gov-286-3625) Sun Dec 29 14:12:55 1991 X-VM-Message-Order: (1 7 4 2 5 6 3 8 9 10 11 12 13 14 15 16 17 18 19) X-VM-Summary-Format: "%n %*%a %-17.17F %-3.3m %2d %4l/%-5c %I\"%s\"\n" X-VM-Labels: nil X-VM-VHeader: ("Resent-" "From:" "Sender:" "To:" "Apparently-To:" "Cc:" "Subject:" "Date:") nil X-VM-Bookmark: 19 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1392" "" " 4" "December" "1991" "02:35:00" "GMT" "Wayne Landsman (301)-286-3625" "landsman at stars.gsfc.nasa.gov" "<2058741 at toto.iv>" "27" "Can BSCALE have a physical meaning?" "^From:" nil nil "12" "1991120402:35:00" "Can BSCALE have a physical meaning?" (number " " mark " Wayne Landsman (3 Dec 4 27/1392 " thread-indent "\"Can BSCALE have a physical meaning?\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: NASA/GSFC-Laboratory for Astronomy and Solar Physics News-Software: VAX/VMS VNEWS 1.4-b1 Nntp-Posting-Host: stars.gsfc.nasa.gov From: landsman at stars.gsfc.nasa.gov (Wayne Landsman (301)-286-3625) Subject: Can BSCALE have a physical meaning? Date: 4 Dec 91 02:35:00 GMT I am working with a group that making FITS files of linearized, digitized, (ultraviolet), photographic images. The dynamic range of these images is well-represented by INTEGER*2 data, and we encourage users to work with this form of the data so that they can easily assess the uncertainties in the data, i.e. where they are in the photographic characteristic curve. (The savings in CPU and disk space for 2048 x 2048 images is also non-trivial.) However, we also include a BSCALE keyword containing an absolute calibration value in ergs/cm**2/s/A/pixel. The problem is that some FITS readers apply the BSCALE factor to the data, and then set BSCALE = 1. The original value of BSCALE is lost and the user cannot recover the original INTEGER*2 intensities and ultimately the photographic densities. So my question is as follows: Is BSCALE always simply a numeric scale factor for representing REAL*4 data using INTEGER*2 numbers? Or can it have a physical meaning for converting between two representations of the data? Should we move or copy the absolute calibration value into another keyword besides BSCALE to make sure that it is always available to the user? Thanks for any suggestions and I apologize for the somewhat anachronistic flavor of the question... Wayne Landsman landsman at stars.gsfc.nasa.gov Hughes/STX (301)-286-3625 From hanisch at stsci.edu Sun Dec 29 14:13:01 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["818" "" " 4" "December" "1991" "22:49:44" "GMT" "Bob Hanisch,N406,4910" "hanisch at stsci.edu" "<8309191 at toto.iv>" "15" "Re: Can BSCALE have a physical meaning?" "^From:" nil nil "12" "1991120422:49:44" "Can BSCALE have a physical meaning?" (number " " mark " Bob Hanisch,N406, Dec 4 15/818 " thread-indent "\"Re: Can BSCALE have a physical meaning?\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: Space Telescope Science Institute Originator: hanisch at iris.stsci.edu From: hanisch at stsci.edu (Bob Hanisch,N406,4910) Subject: Re: Can BSCALE have a physical meaning? Date: 4 Dec 91 22:49:44 GMT >From article <3DEC199122350724 at stars.gsfc.nasa.gov>, by landsman at stars.gsfc.nasa.gov (Wayne Landsman (301)-286-3625): > > Is BSCALE always simply a numeric scale factor for representing REAL*4 data > using INTEGER*2 numbers? Or can it have a physical meaning for converting > between two representations of the data? Should we move or copy the > absolute calibration value into another keyword besides BSCALE to make sure > that it is always available to the user? > I have not encountered any usage of BSCALE to represent anything other than the scale factor for converting integer FITS values back to floating point, and this is the only real significance attached to the keyword in the FITS standard. I would suggest storing the absolute calibration value using a separate keyword. -- Bob Hanisch From warnock at nssdca.gsfc.nasa.gov Sun Dec 29 14:13:04 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1058" "" " 5" "December" "1991" "13:57:00" "GMT" "Archie Warnock" "warnock at nssdca.gsfc.nasa.gov" "<3816733 at toto.iv>" "17" "Re: Can BSCALE have a physical meaning?" "^From:" nil nil "12" "1991120513:57:00" "Can BSCALE have a physical meaning?" (number " " mark " Archie Warnock Dec 5 17/1058 " thread-indent "\"Re: Can BSCALE have a physical meaning?\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: Hughes STX - NASA/NCDS News-Software: VAX/VMS VNEWS 1.41 Nntp-Posting-Host: nssdca.gsfc.nasa.gov From: warnock at nssdca.gsfc.nasa.gov (Archie Warnock) Subject: Re: Can BSCALE have a physical meaning? Date: 5 Dec 91 13:57:00 GMT In article <1991Dec4.224944.7525 at stsci.edu>, hanisch at stsci.edu (Bob Hanisch,N406,4910) writes... >I have not encountered any usage of BSCALE to represent anything other than >the scale factor for converting integer FITS values back to floating point, >and this is the only real significance attached to the keyword in the FITS >standard. I would suggest storing the absolute calibration value using a >separate keyword. I wonder if, perhaps, there ought to be some agreement on what those keywords ought to be. Seems like a common thing to want to store in a header. Certainly those of us who develop image display programs would like to have the physical conversion factors available, so that pixel values can be displayed in those units, rather than raw DN values. ---------------------------------------------------------------------------- -- Archie Warnock Internet: warnock at nssdc.gsfc.nasa.gov -- Hughes STX SPAN: NSSDC::WARNOCK -- NASA/GSFC "Unix - JCL for the 90s" From hanisch at stsci.edu Sun Dec 29 14:13:07 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1259" "" " 5" "December" "1991" "15:29:05" "GMT" "Bob Hanisch,N406,4910" "hanisch at stsci.edu" "<2486674 at toto.iv>" "21" "Re: Can BSCALE have a physical meaning?" "^From:" nil nil "12" "1991120515:29:05" "Can BSCALE have a physical meaning?" (number " " mark " Bob Hanisch,N406, Dec 5 21/1259 " thread-indent "\"Re: Can BSCALE have a physical meaning?\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: Space Telescope Science Institute Originator: hanisch at iris.stsci.edu From: hanisch at stsci.edu (Bob Hanisch,N406,4910) Subject: Re: Can BSCALE have a physical meaning? Date: 5 Dec 91 15:29:05 GMT >From article <5DEC199108575533 at nssdca.gsfc.nasa.gov>, by warnock at nssdca.gsfc.nasa.gov (Archie Warnock): > In article <1991Dec4.224944.7525 at stsci.edu>, hanisch at stsci.edu (Bob Hanisch,N406,4910) writes... >>I have not encountered any usage of BSCALE to represent anything other than >>the scale factor for converting integer FITS values back to floating point, >>and this is the only real significance attached to the keyword in the FITS >>standard. I would suggest storing the absolute calibration value using a >>separate keyword. > > I wonder if, perhaps, there ought to be some agreement on what those > keywords ought to be. Seems like a common thing to want to store in a > header. Certainly those of us who develop image display programs would > like to have the physical conversion factors available, so that pixel > values can be displayed in those units, rather than raw DN values. > Well, there is BUNIT, which defines the physical units of the scaled data values. ST has a set of keywords which are used to define the flux units of spectral data (which depend on whether the flux is per unit wavelength interval or unit frequency interval, for example). However, BUNIT has served adequately in this regard for image data. Bob Hanisch From bhill at stars.gsfc.nasa.gov Sun Dec 29 14:13:11 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1252" "" " 5" "December" "1991" "19:44:00" "GMT" "Robert S. Hill" "bhill at stars.gsfc.nasa.gov" "<4533262 at toto.iv>" "28" "Re: Can BSCALE have a physical meaning?" "^From:" nil nil "12" "1991120519:44:00" "Can BSCALE have a physical meaning?" (number " " mark " Robert S. Hill Dec 5 28/1252 " thread-indent "\"Re: Can BSCALE have a physical meaning?\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: Hughes STX Corp./NASA Goddard Space Flight Center News-Software: VAX/VMS VNEWS 1.4-b1 Nntp-Posting-Host: stars.gsfc.nasa.gov From: bhill at stars.gsfc.nasa.gov (Robert S. Hill) Subject: Re: Can BSCALE have a physical meaning? Date: 5 Dec 91 19:44:00 GMT In article <1991Dec5.152905.19132 at stsci.edu>, hanisch at stsci.edu (Bob Hanisch,N406,4910) writes... >Well, there is BUNIT, which defines the physical units of the scaled data >values. [...] The whole tenor of this thread suggests that section 5.2.2.5 of the standards document (NOST 100-0.2g) has been ignored. There, the envisioned use of BZERO, BSCALE, and BUNIT is -- pretty clearly -- to provide a physical calibration in physicist's units (especially since we are referred to the IAU style guide). \begin{tantrum} What are the FITS readers that can't handle this? The original FITS papers also reflect this same intent. E.g., see p. 369 of A.&A. Suppl. Vol. 44. Didn't anyone else read this stuff? Am I the only one who obeyed instructions? Shame on everybody! at #%$*!( Wack wack wack! \end{tantrum} If BSCALE and BZERO are used solely for stuffing floating-point numbers into integer variables, then IMHO for consistency, you have to make BUNIT = 'ADU' or (in Landsman's and my case) 'E UNITS'. You can't use BSCALE and BZERO to define your arbitrary scaling, then use BUNIT for your physical units. How about something like PHYSCALE, PHYZERO, and PHYUNIT, to be used on the result of applying BSCALE, BZERO, and BUNIT? - Bob Hill From bhill at stars.gsfc.nasa.gov Sun Dec 29 14:13:13 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1166" "" " 5" "December" "1991" "21:19:00" "GMT" "Robert S. Hill" "bhill at stars.gsfc.nasa.gov" "<8184636 at toto.iv>" "24" "Re: Can BSCALE have a physical meaning?" "^From:" nil nil "12" "1991120521:19:00" "Can BSCALE have a physical meaning?" (number " " mark " Robert S. Hill Dec 5 24/1166 " thread-indent "\"Re: Can BSCALE have a physical meaning?\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: Hughes STX Corp./NASA Goddard Space Flight Center News-Software: VAX/VMS VNEWS 1.4-b1 Nntp-Posting-Host: stars.gsfc.nasa.gov From: bhill at stars.gsfc.nasa.gov (Robert S. Hill) Subject: Re: Can BSCALE have a physical meaning? Date: 5 Dec 91 21:19:00 GMT Actually, I think I threw my tantrum a little too soon in that last posting. Yes, I know, this is very mealy-mouthed, on Usenet one should stand by one's flames. ;-) I think I had the question backwards. The problem isn't that FITS readers fail to apply BZERO, BSCALE, and BUNIT properly; it's that the stored numbers in the file are regarded as being, per se, meaningless *unless* BZERO, BSCALE, and BUNIT are applied. But for Wayne's and my project, the stored numbers will always be meaningful as instrumental units. It still seems apparent that for our purposes we need a couple of layers of conversion, since we don't want users to lose track of instrumental units, which have implications for saturation and for error analysis. - Bob Hill -------------------------------------------------------------------------------- Robert S. Hill Internet: BHILL at STARS.GSFC.NASA.GOV Hughes STX Corp. SPAN: STARS::BHILL Code 680 Phone: 301/286-3624 NASA/Goddard Space Flight Center Greenbelt, MD 20771 ------------------------------------------------------------------------------- From hanisch at stsci.edu Sun Dec 29 14:13:17 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["2294" "" " 6" "December" "1991" "22:07:41" "GMT" "Bob Hanisch,N406,4910" "hanisch at stsci.edu" "<3586124 at toto.iv>" "44" "Re: Can BSCALE have a physical meaning?" "^From:" nil nil "12" "1991120622:07:41" "Can BSCALE have a physical meaning?" (number " " mark " Bob Hanisch,N406, Dec 6 44/2294 " thread-indent "\"Re: Can BSCALE have a physical meaning?\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: Space Telescope Science Institute Originator: hanisch at iris.stsci.edu From: hanisch at stsci.edu (Bob Hanisch,N406,4910) Subject: Re: Can BSCALE have a physical meaning? Date: 6 Dec 91 22:07:41 GMT >From article <5DEC199116190859 at stars.gsfc.nasa.gov>, by bhill at stars.gsfc.nasa.gov (Robert S. Hill): > Actually, I think I threw my tantrum a little too soon in that last > posting. Yes, I know, this is very mealy-mouthed, on Usenet one should > stand by one's flames. ;-) > > I think I had the question backwards. The problem isn't that FITS > readers fail to apply BZERO, BSCALE, and BUNIT properly; it's that the > stored numbers in the file are regarded as being, per se, meaningless > *unless* BZERO, BSCALE, and BUNIT are applied. But for Wayne's and > my project, the stored numbers will always be meaningful as > instrumental units. > > It still seems apparent that for our purposes we need a couple of layers > of conversion, since we don't want users to lose track of instrumental > units, which have implications for saturation and for error analysis. > > - Bob Hill > Thanks, Bob, for clarifying your position on this. I couldn't quite believe the first posting you wrote. The FITS i/o packages I'm familiar with treat the data, after application of BSCALE and BZERO, to be in the appropriate physical units (i.e., units of BUNIT). If this is not the case, then I agree with Chris Flatters' previous posting (in response to a different message) that the writer of the data has made an error. In the UIT case it seems that you are trying to kill two birds with one stone, which is laudable in the sense of economizing on data storage, but potentially confusing in terms of the subsequent interpretation. For example, for HST we deliver to observers both the raw data and calibrated data. The calibration is more than just a scaling, so we cannot avail ourselves of the situation apparently available for UIT images. However, my recommedation for UIT would be to export your integer data using BSCALE = 1., BZERO = 0., and BUNIT = 'DN' or whatever is appropriate. You can provide a scaling factor elsewhere in the header that allows users to convert to flux units, but I think it would be unwise to have this applied automatically like BSCALE. I expect that in most data analysis systems it would be pretty straightforward for users to write a procedure that extracts the flux scale value from the header and multiplies the data to produce a new image. Bob Hanisch From gibson at crisium.geop.ubc.ca Sun Dec 29 14:13:23 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["3030" "Thu" " 5" "December" "1991" "20:38:04" "GMT" "Brad Gibson" "gibson at crisium.geop.ubc.ca" "<2162944 at toto.iv>" "69" "Beginner Question -- Absolute Fluxes" "^From:" nil nil "12" "1991120520:38:04" "Beginner Question -- Absolute Fluxes" (number " " mark " Brad Gibson Dec 5 69/3030 " thread-indent "\"Beginner Question -- Absolute Fluxes\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: Dept. of Astronomy / Univ. of British Columbia From: gibson at crisium.geop.ubc.ca (Brad Gibson) Subject: Beginner Question -- Absolute Fluxes Date: Thu, 5 Dec 91 20:38:04 GMT ------------------------------------------------------------------------------ -- I have been "playing" with some fits 1D spectra of late and have some very novice questions (warning: I'm a first time user of "real" data -- I usually live in the bizarre realm of theory). First the source: an atlas of synthetic stellar spectra (Pickles, A. 1985, ApJS, 59, 33). Note: As I haven't had any luck in hearing from Andrew Pickles himself, I figured I would take a shot in the dark and see if anyone on the net had any ideas before I contacted him again. What I want?: real fluxes (in ergs/sec/cm^2/Angstrom). What do I have?: one-D spectra in which the ordinate is liners in F(lambda) and the spectra have been normalized to 100 in the wavelength region 5450-5500A. My problem: I don't know explicitly what the normalization factor is for each spectrum in the atlas (48 of different spectral type and luminosity class). I have included below the fits header for one of the spectra (OV). As my familiarity with fits/iraf is less than minimal, perhaps someone can let me know if there is a simple way to invert this normalized data to real fluxes. Naively, I though that if I simply took the normalized data (values from about 0 to a few hundred, depending upon spectrum under consideration), multiplied by BSCALE and then added BZERO, I would end up with the REAL (i.e., flux) result ... unfortunately this does not lead to the desired numbers. Maybe there is no simple one step way for me to obtain the absolute fluxes, but I figure it can't hurt to ask. Thanks in advance for any help! Cheers, Brad SIMPLE = T / FITS STANDARD BITPIX = 32 / FITS BITS/PIXEL NAXIS = 3 / NUMBER OF AXES NAXIS1 = 2134 / NAXIS2 = 1 / NAXIS3 = 1 / BSCALE = 1.0127740409E-7 / REAL = TAPE*BSCALE + BZERO BZERO = 2.2793748140E2 / OBJECT = 'OV ' / ORIGIN = 'KPNO-IRAF' / DATE = '21-06-91' / IRAFNAME= 'slib001.imh' / NAME OF IRAF IMAGE FILE IRAF-MAX= 4.454288E2 / DATA MAX IRAF-MIN= 1.044613E1 / DATA MIN IRAF-B/P= 32 / DATA BITS/PIXEL IRAFTYPE= 'FLOATING' / COMMENT = SADFILE:- DISK$USER:[PICKLES.STARLIB]SSS MAP 1 CTYPE1 = 'LAMBDA ' / METRES PIXOR = 'CENTRE ' / VALUE REFERS TO CENTRE OF PIXEL BUNIT = 'FLAMBDA ' / ERG/CM**2/SEC/A CRVAL1 = 3600E-10 / METRES CDELT1 = 3E-10 / METRES HISTORY 'KAPTEYN ' / END -- ------------------------------------------------------------------------------ Brad K. Gibson INTERNET: gibson at geop.ubc.ca Dept. of Geophysics & Astronomy BITNET: userbgib at ubcmtsg.bitnet #129-2219 Main Mall University of British Columbia Vancouver, British Columbia, Canada V6T 1Z4 ------------------------------------------------------------------------------ From cflatter at nrao.edu Sun Dec 29 14:13:26 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1306" "Thu" " 5" "December" "1991" "22:21:55" "GMT" "Chris Flatters" "cflatter at nrao.edu" "<7260360 at toto.iv>" "25" "Re: Beginner Question -- Absolute Fluxes" "^From:" nil nil "12" "1991120522:21:55" "Beginner Question -- Absolute Fluxes" (number " " mark " Chris Flatters Dec 5 25/1306 " thread-indent "\"Re: Beginner Question -- Absolute Fluxes\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Reply-To: cflatter at nrao.edu Organization: NRAO From: cflatter at nrao.edu (Chris Flatters) Subject: Re: Beginner Question -- Absolute Fluxes Date: Thu, 5 Dec 1991 22:21:55 GMT In article 10584 at cs.ubc.ca, gibson at crisium.geop.ubc.ca (Brad Gibson) writes: >I have included below the fits header for one of the spectra (OV). As my >familiarity with fits/iraf is less than minimal, perhaps someone can let me >know if there is a simple way to invert this normalized data to real fluxes. >Naively, I though that if I simply took the normalized data (values from about >0 to a few hundred, depending upon spectrum under consideration), multiplied by >BSCALE and then added BZERO, I would end up with the REAL (i.e., flux) result >.... unfortunately this does not lead to the desired numbers. This header states that the data on the tape are already in ergs cm^-2 sec^-1 angstrom^-1 (sigh - whatever happened to SI units) and have a range of 10.45 to 445.43. If the data are not really in ergs per whatever the header is lying and does not provide the necessary information to recover the true values. (BSCALE and BZERO are applied to the 32-bit integer values in the FITS file). ====================================================================== Chris Flatters | cflatter at nrao.edu AIPS Scientific Programmer | ====================================================================== Opinions expressed in this message do not necessarily reflect NRAO policy. From pmurphy at baboon.cv.nrao.edu Sun Dec 29 14:13:30 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1602" "Fri" " 6" "December" "1991" "15:19:13" "GMT" "Pat Murphy" "pmurphy at baboon.cv.nrao.edu" "<2422952 at toto.iv>" "31" "Re: FITS" "^From:" nil nil "12" "1991120615:19:13" "FITS" (number " " mark " Pat Murphy Dec 6 31/1602 " thread-indent "\"Re: FITS\"\n") nil] nil) Newsgroups: comp.graphics,alt.sci.astro.fits In-Reply-To: philippe at cli52ch.edf.fr's message of 3 Dec 91 14: 26:11 GMT Followup-To: alt.sci.astro.fits Organization: National Radio Astronomy Observatory Distribution: comp.graphics From: pmurphy at baboon.cv.nrao.edu (Pat Murphy) Subject: Re: FITS Date: Fri, 6 Dec 1991 15:19:13 GMT In article <7822 at edfder1.fr> of comp.graphics, philippe at cli52ch.edf.fr (Philippe SUIGNARD) writes: What is FITS ? Where can I find it ? Someone else has already answered the second question (although note that several existing astronomy-basedimage processing packages already support FITS, e.g. AIPS, IRAF, STSDAS, MIDAS, etc. etc. As for "What is FITS", it stands for "Flexible Image Transport System", it was devised in the early 80's by a handful of astronomers and programmers at several institutions worldwide as a way of allowing for easy interchange of astronomical data. The primary reference is Wells, Greisen, and Harten (1981) Astronomy and Astrophysics Supplement 44, p. 363. There are other follow-on articles (p. 371 of the same volume for one) but I don't have the references offhand, only the drafts and preprints of them. You should check the alt.sci.astro.fits newsgroup if you want to know about ongoing debate over the future direction of fits, or if you have any questions (note I have referred any followup there). Hope this helps. - Pat -- ========================================================================== | Patrick P. Murphy, Ph.D. Scientific Programming Analyst | | National Radio Astronomy Observatory Net: pmurphy at nrao.edu | | 520 Edgemont Road or: uunet!nrao.edu!pmurphy | | Charlottesville, VA 22903-2475 Phone: (804) 296-0372 | | "I don't believe in the no-win scenario" --- James T. Kirk | ========================================================================== From bschlesinger at nssdca.gsfc.nasa.gov Sun Dec 29 14:13:34 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["3342" "" " 6" "December" "1991" "17:16:00" "GMT" "Barry Schlesinger" "bschlesinger at nssdca.gsfc.nasa.gov" "<3498673 at toto.iv>" "77" "Re: FITS" "^From:" nil nil "12" "1991120617:16:00" "FITS" (number " " mark " Barry Schlesinger Dec 6 77/3342 " thread-indent "\"Re: FITS\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Summary: FITS references Followup-To: alt.sci.astro.fits Distribution: comp.graphics, alt.sci.astro.fits Organization: NASA - Goddard Space Flight Center News-Software: VAX/VMS VNEWS 1.41 Nntp-Posting-Host: nssdca.gsfc.nasa.gov From: bschlesinger at nssdca.gsfc.nasa.gov (Barry Schlesinger) Subject: Re: FITS Date: 6 Dec 91 17:16:00 GMT In article , pmurphy at baboon.cv.nrao.edu (Pat Murphy) writes... >In article <7822 at edfder1.fr> of comp.graphics, philippe at cli52ch.edf.fr >(Philippe SUIGNARD) writes: >> >> What is FITS ? ... >> > ... > The primary reference is >Wells, Greisen, and Harten (1981) Astronomy and Astrophysics >Supplement 44, p. 363. There are other follow-on articles ... >but I don't have the references offhand ... The fundamental references on FITS are the following four papers, often referred to collectively as the "Four FITS Papers". These papers are the formal standard for FITS, endorsed by the International Astronomical Union (IAU). Wells, D. C., Greisen, E. W., and Harten, R. H., "FITS: a flexible image tranport system," Astronomy and Astrophysics Supplement Series, 44, 363-370, 1981. Greisen, E. W. and Harten, R. H., "An extension of FITS for small arrays of data," Astronomy and Astrophysics Supplement Series, 44, 371-374, 1981. (NOTE: The format described in this paper has been used almost exclusively to transport radio interferometry and is likely to be replaced by other formats in the future. Writing data other than radio interferometry data using this format is not recommended.) Grosbol, P., Harten, R. H., Greisen, E. W., and Wells, D. C., "Generalized extensions and blocking factors for FITS," Astronomy and Astrophysics Supplement Series, 73, 359-364, 1988. Harten, R. H., Grosbol. P., Greisen, E. W., and Wells, D. C., "The FITS tables extension, Astronomy and Astrophysics Supplement Series, 73, 365-372, 1988. A User's Guide for FITS, designed to be a tutorial for new FITS users, is available from the NASA/OSSA Office of Standards and Technology (NOST). In addition to presenting the rules of FITS, it provides some of the history and reasoning behind the choice of the rules, adds recommendations on good practices, and discusses current developments in FITS. This document is available only in hard copy form. NASA is sponsoring development of a formal standard for FITS, designed to be a codification of FITS as endorsed by the IAU. The current draft, the NASA/OSSA Office of Science and Technology (NOST) Draft Standard for Implementation of FITS, version 0.2, is available by anonymous ftp from nssdca.gsfc.nasa.gov, in the subdirectory FITS. A README explains how to obtain access. As the term "draft" implies, it is still under review, and caution should be exercising when using it as a FITS reference. A detailed proposal for a Binary Table extension is now out for discussion. It is available by anonymous ftp from fits.cx.nrao.edu, subdirectory \FITS\Documents. Much of this documentation can be obtained from the NOST Librarian. Paper copies of the User's Guide and either paper or electronic copies of the Draft Implementation Standard, for those without ftp access, are available. Because of restrictions set by the copyright holder, NOST can send copies of the four FITS papers only to non-profit organizations. The addresses of the NOST are as follows: (Postal) NASA/OSSA Office of Standards and Technology Code 930.8 Goddard Space Flight Center Greenbelt MD 20771 USA (Internet) nost at nssdca.gsfc.nasa.gov (DECnet) NSSDCA::NOST Barry M. Schlesinger Coordinator, NOST FITS Support Office From dwells at fits.cx.nrao.edu Sun Dec 29 14:13:38 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1864" "Wed" "18" "December" "1991" "19:57:32" "GMT" "Don Wells" "dwells at fits.cx.nrao.edu" "<2876417 at toto.iv>" "37" "NRAO.BITNET is fading away" "^From:" nil nil "12" "1991121819:57:32" "NRAO.BITNET is fading away" (number " " mark " Don Wells Dec 18 37/1864 " thread-indent "\"NRAO.BITNET is fading away\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: National Radio Astronomy Observatory From: dwells at fits.cx.nrao.edu (Don Wells) Subject: NRAO.BITNET is fading away Date: Wed, 18 Dec 1991 19:57:32 GMT NRAO.BITNET is fading away The NRAO Computer Division announced in the October issue of the NRAO Newsletter that direct BITnet service to NRAO would be discontinued when host "CVAX" is removed in Charlottesville at the end of December. In fact the BITnet routing tables update on the 15th of each month, and so the order to logically disconnect had to be issued early in the month. It was issued several weeks ago. It has taken effect, and NRAO is now mostly unreachable via BITnet. A login message on CVAX today says: 18 Dec 91: * Our request to be dropped from Bitnet is beginning to take effect. CUNYVM no longer knows the Bitnet node NRAO. As other Bitnet nodes update their tables, incoming Bitnet mail will fail more often. Outbound Bitnet mail can still be sent through the CVAX Bitnet facility until Dec 31. After that, all CVAX Bitnet service will be ended. Ruth Milner, system manager at the AOC, says: "I had a phone call Monday from someone trying to reach [an AOC user via BITnet]. After telling him what address to use instead, I asked whether he had received the October Newsletter. He had, but admitted he hadn't read it. So I told him about the article describing the networking changes and suggested (very politely, of course) that he might want to read it over to see whether anything else affected him.. [The termination order] definitely appears to be taking effect." BITnet has served NRAO and its user community well for the past five years, but that era has ended. Long live the Internet! Donald C. Wells Associate Scientist dwells at nrao.edu National Radio Astronomy Observatory +1-804-296-0277 520 Edgemont Road Fax= +1-804-296-0278 Charlottesville, Virginia 22903-2475 USA 78:31.1W, 38:02.2N From eso!pgrosbol at fits.cx.nrao.edu Sun Dec 29 14:15:04 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["2049" "Thu" "19" "December" "1991" "09:24:48" "GMT" "eso!pgrosbol at fits.cx.nrao.edu" "eso!pgrosbol at fits.cx.nrao.edu" "<5798880 at toto.iv>" "37" "Important FITS issues." "^From:" nil nil "12" "1991121909:24:48" "Important FITS issues." (number " " mark " eso!pgrosbol at fits Dec 19 37/2049 " thread-indent "\"Important FITS issues.\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: National Radio Astronomy Observatory From: Subject: Important FITS issues. Date: Thu, 19 Dec 1991 09:24:48 GMT Garching, Dec. 19, 1991 Dear FITS colleagues, First I would like to apologize for my silence during the first months of the alt.sci.astro.fits newsgroup and fitsbits-exploder. Unfortunately, I have been very busy with internal ESO matters which had to have a higher priority. I hope that these issues now have settled which would give my more time for FITS matters. The two most important items to be discussed in the very near future are: 1) Binary table extension: In order to avoid further delays in the official procedure to accept this extension as a standard extension, I urge you to get a copy of the draft proposal (e.g. through ftp or the NASA FITS Support office) and read it carefully. Please post any comments before January 31, 1992. This would make it possible to include possible revisions before submitting the draft proposal to the Local FITS Groups in the start of March. Note that a FITS test file with a binary extension is available through ftp. 2) Blocking: A draft proposal for blocking of FITS files on different media e.g. 8mm Exabyte, DDS/DAT and QIC. I would also like to call for comments on this proposal before January 31, 1992, in order to forward it to the Local FITS Groups. A very limited number of test tape has been made available but reports on exchange of FITS files on such media are welcomed. I will emit the official list of FITS extensions to the FITS exploder and have the updated version available submitted to the NASA FITS Support Office. There have been several problems for people who wanted to reach me on my Internet address 'pgrosbol at eso.org'. These problems unfortunately still exist and is caused by ambiguous routing information from different nodes in USA. We hope that they can be resolved soon but until then you may mail my on SPAN: 'ESO::PGROSBOL', BITNET: 'PGROSBOL at DGAESO51' or UUCP: 'eso!pgrosbol'. With my best regards and seasonal greetings, Preben Grosbol Chairman, IAU FITS WG From dwells at fits.cx.nrao.edu Sun Dec 29 14:15:59 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["908" "Thu" "19" "December" "1991" "19:19:59" "GMT" "Don Wells" "dwells at fits.cx.nrao.edu" "<4358618 at toto.iv>" "16" "Create sci.astro.fits?" "^From:" nil nil "12" "1991121919:19:59" "Create sci.astro.fits?" (number " " mark " Don Wells Dec 19 16/908 " thread-indent "\"Create sci.astro.fits?\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: National Radio Astronomy Observatory, Charlottesville, VA Distribution: alt From: dwells at fits.cx.nrao.edu (Don Wells) Subject: Create sci.astro.fits? Date: Thu, 19 Dec 1991 19:19:59 GMT About six months have passed since I created alt.sci.astro.fits. I believe that we have demonstrated that this newsgroup fills a permanent need. Therefore, I think that the time has come to consider forming sci.astro.fits. Does anyone object to doing this, or to the name "sci.astro.fits"? If so, send Email to me privately. Assuming that I hear no objections, early in January I expect that I will initiate the formal USEnet procedure for creating sci.astro.fits. Probably the RFD period will be most of January and the CFV period will be most of February. If all goes well we should have our newsgroup by 1-March-92. -- Donald C. Wells Associate Scientist dwells at nrao.edu National Radio Astronomy Observatory +1-804-296-0277 520 Edgemont Road Fax= +1-804-296-0278 Charlottesville, Virginia 22903-2475 USA 78:31.1W, 38:02.2N From eso!pgrosbol at fits.cx.nrao.edu Sun Dec 29 14:16:02 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["2519" "Fri" "20" "December" "1991" "10:24:45" "GMT" "eso!pgrosbol at fits.cx.nrao.edu" "eso!pgrosbol at fits.cx.nrao.edu" "<8154465 at toto.iv>" "53" "Registered Extension to FITS" "^From:" nil nil "12" "1991122010:24:45" "Registered Extension to FITS" (number " " mark " eso!pgrosbol at fits Dec 20 53/2519 " thread-indent "\"Registered Extension to FITS\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: National Radio Astronomy Observatory From: Subject: Registered Extension to FITS Date: Fri, 20 Dec 1991 10:24:45 GMT Registered Extension to FITS IAU FITS Working Group Preben Grosbol 1991-Dec-10 Introduction ------------ Extension to the basic FITS format can be defined as specified in Grosbol et al. (Astron. Astrophys. Suppl. 73, p359-364, 1988). The IAU FITS Working Group under Commission 5 registers the names of such conforming extension. The status of a given extension can have one of the following levels: Status Remarks --------------------------------------------------------------- S Standard FITS extension accepted by the IAU FITS WG and recommended by the IAU. P Proposal for FITS extension accepted by local FITS committees but not yet by the IAU FITS WG. D Draft proposal to be discussed in local FITS committees. R Reserver FITS extension name for which a full draft proposal has not yet been submitted. L Local FITS extension which has a limited scope only. The table below gives a list of known names of FITS extension formats, their status and reference organization: Ext-name Status Ref. Remarks -------------------------------------------------------------------- 'TABLE ' S IAU Defined in Astron. Astrophys. Suppl. 73, p365-372, (1988). 'BINTABLE' D IAU Draft Proposal by W.Cotton and D.Tody September 20, 1991. 'IMAGE ' R IUE Suggested extension name (by J.R.Munoz); No full proposal submitted. 'FILEMARK' R NRAO Suggested extension name (by D.Wells); No full proposal submitted. 'DUMP ' R - Suggested extension name for binary dumps; No full proposal submitted. 'A3DTABLE' L NRAO Extension used by AIPS and defined in the 'Going AIPS' Manual Chapter 14. 'IUEIMAGE' L IUE Local extension defined for archiving of special IUE data products. Anyone who want to register a FITS extension name should contact either the NASA FITS Support Office ('bschlesinger at nssdca.gsfc.nasa.gov') or the chairman of the IAU FITS Working Group ('pgrosbol at eso.org'). A short description and justification should be submitted together with the request for registration. From bschlesinger at nssdca.gsfc.nasa.gov Sun Dec 29 14:16:10 1991 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["4484" "" "27" "December" "1991" "21:33:00" "GMT" "Barry Schlesinger" "bschlesinger at nssdca.gsfc.nasa.gov" "<5790421 at toto.iv>" "89" "Version 0.3b FITS Draft NOST standard" "^From:" nil nil "12" "1991122721:33:00" "Version 0.3b FITS Draft NOST standard" (number " " mark " Barry Schlesinger Dec 27 89/4484 " thread-indent "\"Version 0.3b FITS Draft NOST standard\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Keywords: FITS, Standards, NASA Organization: NASA - Goddard Space Flight Center News-Software: VAX/VMS VNEWS 1.41 Nntp-Posting-Host: nssdca.gsfc.nasa.gov From: bschlesinger at nssdca.gsfc.nasa.gov (Barry Schlesinger) Subject: Version 0.3b FITS Draft NOST standard Date: 27 Dec 91 21:33:00 GMT Version 0.3b of the NASA/OSSA Office of Standards and Technology (NOST) Draft Standard for Implementation of the Flexible Image Transport System (FITS) is now available on the National Space Science Data Center computers. This version is the result of the Technical Panel review of the comments received on version 0.2 of the standard during the period June-September 1991. The most significant changes are elimination of the restriction on alphabetic characters to upper case in table field names (value of TTYPEn keywords) and replacement of the informational appendix describing the AIPS A3DTABLE construct with text describing the BINTABLE binary tables proposal. Given the nature of the comments received, the Panel concluded that, only minor revisions, if any, to version 0.3 would be necessary before it could be submitted to the NOST Accreditation Panel for approval as a NASA Standard and to the IAU FITS Working Group for endorsement as the Standard for FITS. No general community comment period is envisioned, although comments or questions can be sent to the address at the end of this announcement. Version 0.3b is being reviewed by the Technical Panel to ensure that that it properly incorporates the Panel decisions. When that review is complete, a revised version will be announced and released, if necessary; any differences from version 0.3b are likely to be small. The new version is being made generally available now to allow those individuals or groups who may have been using earlier drafts as a reference on FITS, in spite of their provisional status, to replace their copies of the earlier draft with the improved one. As before, the form of the Standard is not final and should not be considered to supersede the existing FITS documentation. As of this announcement, only the ftp version is available, although hard copies should be available from the NOST librarian in 1-2 weeks. The procedure for ftp access is the same as before. Copies are available in LaTeX, PostScript, and flat ASCII. The NSSDCA computer is a VAX/VMS 9410; therefore, file names are case insensitive, and disks and subdirectories are designated as ANON_DIR:[FITS] for the disk "ANON_DIR" and the directory "FITS". Retrieve the README. file first. It describes the files in the FITS directory and provides more detail on session and retrieval procedures. Internet (TCP/IP) SPAN (DECnet) ---------------------------------------------------------------------- Name: NSSDCA.GSFC.NASA.GOV NSSDCA Address: 128.183.36.23 6.133 (6277) ---------------------------------------------------------------------- =============================================================================== == default DECnet README. copy via SPAN == =============================================================================== ndadsa $ copy/log nssdca::anon_dir:[fits]readme. * %COPY-S-COPIED, NSSDCA::ANON_DIR:[FITS]README.;1 copied to DISKA":[MEV]README.;2 (1 block) =============================================================================== == Anonymous FTP README. copy via Internet == =============================================================================== ndadsa $ ftp nssdca.gsfc.nasa.gov NDADSA.GSFC.NASA.GOV MultiNet FTP user process 2.2(100) Connection opened (Assuming 8-bit connections) user anonymous cd fits get readme.;1 readme. quit " "89" "version 0.3b FITS Draft NOST Standard(corrected)" "^From:" nil nil "12" "1991123013:50:00" "version 0.3b FITS Draft NOST Standard(corrected)" (number " " mark " Barry Schlesinger Dec 30 89/4478 " thread-indent "\"version 0.3b FITS Draft NOST Standard(corrected)\"\n") nil] nil) Newsgroups: alt.sci.astro.fits Organization: NASA - Goddard Space Flight Center News-Software: VAX/VMS VNEWS 1.41 Nntp-Posting-Host: nssdca.gsfc.nasa.gov From: bschlesinger at nssdca.gsfc.nasa.gov (Barry Schlesinger) Subject: version 0.3b FITS Draft NOST Standard(corrected) Date: 30 Dec 91 13:50:00 GMT Version 0.3b of the NASA/OSSA Office of Standards and Technology (NOST) Draft Standard for Implementation of the Flexible Image Transport System (FITS) is now available on the National Space Science Data Center computers. This version is the result of the Technical Panel review of the comments received on version 0.2 of the standard during the period June-September 1991. The most significant changes are elimination of the restriction on alphabetic characters to upper case in table field names (value of TTYPEn keywords) and replacement of the informational appendix describing the AIPS A3DTABLE construct with text describing the BINTABLE binary tables proposal. Given the nature of the comments received, the Panel concluded that, only minor revisions, if any, to version 0.3 would be necessary before it could be submitted to the NOST Accreditation Panel for approval as a NASA Standard and to the IAU FITS Working Group for endorsement as the Standard for FITS. No general community comment period is envisioned, although comments or questions can be sent to the address at the end of this announcement. Version 0.3b is being reviewed by the Technical Panel to ensure that that it properly incorporates the Panel decisions. When that review is complete, a revised version will be announced and released, if necessary; any differences from version 0.3b are likely to be small. The new version is being made generally available now to allow those individuals or groups who may have been using earlier drafts as a reference on FITS, in spite of their provisional status, to replace their copies of the earlier draft with the improved one. As before, the form of the Standard is not final and should not be considered to supersede the existing FITS documentation. As of this announcement, only the ftp version is available, although hard copies should be available from the NOST librarian in 1-2 weeks. The procedure for ftp access is the same as before. Copies are available in LaTeX, PostScript, and flat ASCII. The NSSDCA computer is a VAX/VMS 9410; therefore, file names are case insensitive, and disks and subdirectories are designated as ANON_DIR:[FITS] for the disk "ANON_DIR" and the directory "FITS". Retrieve the README. file first. It describes the files in the FITS directory and provides more detail on session and retrieval procedures. Internet (TCP/IP) DECnet ---------------------------------------------------------------------- Name: NSSDCA.GSFC.NASA.GOV NSSDCA Address: 128.183.36.23 15.188 (15548) ---------------------------------------------------------------------- =============================================================================== == DECnet README. == =============================================================================== ndadsa $ copy/log nssdca::anon_dir:[fits]readme. * %COPY-S-COPIED, NSSDCA::ANON_DIR:[FITS]README.;1 copied to DISKA":[MEV]README.;2 (1 block) =============================================================================== == Anonymous FTP README. copy via Internet == =============================================================================== ndadsa $ ftp nssdca.gsfc.nasa.gov NDADSA.GSFC.NASA.GOV MultiNet FTP user process 2.2(100) Connection opened (Assuming 8-bit connections) user anonymous cd fits get readme.;1 readme. quit , youngs at ccu.umanitoba.ca (Scott D. Young) writes... > Can someone please send me information on any PD programs that display > FITS format images on either a Mac or IBM? I also need a program that > converts FITS to GIF format. Thanks in advance. IMDISP reads FITS images as long as they're integer. It's PD, it's for MS-DOS, and it can save displayed images as GIF. It also supports several SuperVGA displays. You can find it in /mirrors/msdos/graphics at wuarchive.wustl.edu. ---------------------------------------------------------------------------- -- Archie Warnock Internet: warnock at nssdc.gsfc.nasa.gov -- Hughes STX SPAN: NSSDC::WARNOCK -- NASA/GSFC "Unix - JCL for the 90s"