From fitsbits-request Thu Jan 7 09:48:26 1993 X-VM-VHeader: ("From:" "Sender:" "Resent-From" "To:" "Apparently-To:" "Cc:" "Subject:" "Date:" "Resent-Date:") nil X-VM-Bookmark: 5 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1762" "Thu" "7" "January" "1993" "14:07:00" "GMT" "Barry Schlesinger" "bschlesinger at nssdca.gsfc.nasa.gov " nil "45" "NOST FITS User's Guide new version 3.0" "^From:" nil nil "1"]) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA11457; Thu, 7 Jan 93 09:48:26 EST Return-Path: Message-Id: <7JAN199309075725 at nssdca.gsfc.nasa.gov> Organization: NASA - Goddard Space Flight Center Path: cv3.cv.nrao.edu!uvaarpa!darwin.sura.net!jvnc.net!newsserver.jvnc.net!yale.edu!think.com!ames!nsisrv!nssdca.gsfc.nasa.gov!bschlesinger From: bschlesinger at nssdca.gsfc.nasa.gov (Barry Schlesinger) Sender: fitsbits-request at fits.CV.NRAO.EDU To: fitsbits at fits.CV.NRAO.EDU Subject: NOST FITS User's Guide new version 3.0 Date: Thu, 7 Jan 1993 14:07:00 GMT Version 3.0 of the NOST FITS User's Guide is now available. It describes binary tables as defined in the proposed BINTABLE extension, as opposed to the preliminary NRAO A3DTABLE proposal that was discussed in version 2. The discussion of new extension proposals has been brought up to date. A new section has been added on World Coordinates, based primarily on the Wells and Hanisch proposal and AIPS memos 27 and 46; among its contents are the CD matrix proposal and an outline of projections from the celestial sphere to the data array plane. The section on network resources has been greatly expanded. Changes and additions have been made throughout the text. Version 3.0 is currently available in printed form only. Steps are under way toward producing an electronic version. The initial process will be to try to capture the PostScript file, but the goal is to eventually have the Guide available in the same three forms as the Standard: LaTeX, PostScript and flat ASCII. Suggestions on how to expedite this process are welcome. The native format is Microsoft Word on Macintosh. A copy of version 3.0 will be sent to all who were sent a copy of version 2.0. Others may obtain a copy from the NOST librarian. The contact points are the following: (Postal) NASA/OSSA Office of Standards and Technology Code 633.2 Goddard Space Flight Center Greenbelt MD 20771 USA (Internet) nost at nssdca.gsfc.nasa.gov (DECnet) NCF::NOST Telephone: +1-301-286-3575 8 a. m. - 5 p. m., U. S. Eastern Time If the Librarian is unavailable, a phone mail system takes the call after four rings. Barry M. Schlesinger Coordinator, NASA/NSSDC NOST FITS Support Office +1-301-513-1634 fits at nssdca.gsfc.nasa.gov NCF::FITS From fitsbits-request Wed Jan 13 09:55:01 1993 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["799" "Wed" "13" "January" "1993" "13:18:06" "GMT" "phjj at ruchem.ru.ac.za" "phjj at ruchem.ru.ac.za" nil "15" "Coordinate specs" "^From:" nil nil "1"]) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA03518; Wed, 13 Jan 93 09:55:01 EST Return-Path: Message-Id: <1993Jan13.131600.14683 at hippo.ru.ac.za> Organization: Rhodes University, Grahamstown, SA Path: cv3.cv.nrao.edu!uvaarpa!darwin.sura.net!newsserver.jvnc.net!yale.edu!think.com!rpi!batcomputer!cornell!uw-beaver!news.tek.com!psgrain!hippo!ruchem.ru.ac.za!PHJJ Reply-To: phjj at ruchem.ru.ac.za From: phjj at ruchem.ru.ac.za Sender: fitsbits-request at fits.CV.NRAO.EDU To: fitsbits at fits.CV.NRAO.EDU Subject: Coordinate specs Date: Wed, 13 Jan 1993 13:18:06 GMT Could someone please e-mail me the proposals for specifying image coordinates (perhaps AIPS memos 27 & 46)? Are they something like the NOD2 coordinate matrix? Thanks Justin ====================================================~~~~~*~~~~~~~~~~~*~~~~~~~~~ Justin Jonas Radio Astronomy Group, /V\ _____ __ __ Dept. Physics & Electronics, \ / \ / /____/ \ /_/| /_/| Rhodes University, \/ |v| \/ | __ \ /| | | | | | | Grahamstown 6140, South Africa \__|#|__/ 26m | |__) |/ | | | | | | Internet: phjj at ruchem.ru.ac.za HartRAO /X\ dish | ___ \ \ | \_\/ | | phjj at hippo.ru.ac.za /\/|\/\ |_|/ \__\/ \___/|_|/ Tel: +27(461)22023 ext 452 ____/\/__|__\/\____ From fitsbits-request Thu Jan 21 17:30:17 1993 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["9783" "Thu" "21" "January" "1993" "20:00:00" "GMT" "Barry Schlesinger" "bschlesinger at nssdca.gsfc.nasa.gov " nil "199" "FITS basics and information" "^From:" nil nil "1"]) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA12691; Thu, 21 Jan 93 17:30:17 EST Return-Path: Message-Id: <21JAN199315003692 at nssdca.gsfc.nasa.gov> Organization: NASA - Goddard Space Flight Center Path: cv3.cv.nrao.edu!uvaarpa!concert!gatech!emory!sol.ctr.columbia.edu!spool.mu.edu!agate!ames!nsisrv!nssdca.gsfc.nasa.gov!bschlesinger From: bschlesinger at nssdca.gsfc.nasa.gov (Barry Schlesinger) Sender: fitsbits-request at fits.CV.NRAO.EDU To: fitsbits at fits.CV.NRAO.EDU Subject: FITS basics and information Date: Thu, 21 Jan 1993 20:00:00 GMT This basic FITS information is posted and updated periodically for the benefit of new readers and the reference of old readers. FITS (Flexible Image Transport System) is a data format designed to provide a means for convenient exchange of astronomical data between installations whose standard internal formats and hardware differ. A FITS file is composed of a sequence of Header Data Units (HDUs). The header consists of keyword=value statements, which describe the format and organization of the data in the HDU and may also provide additional information, for example, about the instrument or the history of the data. The data follow, structured as the header specifies. The data section of the HDU may contain a digital image, but, except for the first, IT DOESN'T HAVE TO. Other possible formats include tables and multidimensional matrices that are not images. The first HDU must contain a multidimensional matrix or no data at all; the data in subsequent HDUs, called extensions, may be of any type, consistent with certain rules. The "Image" in the name comes from the original use of the format to transport digital images, but it's not just for images any more. FITS is not principally a graphics format designed for the transfer of pictures; it does not incorporate "FITS viewers", packages for decoding the data into an image. Users must develop or obtain separate software to convert the data from the FITS file into a form that can be readily displayed. As has been discussed in this newsgroup, and in alt.sci.astro.fits before it, the Extended Portable Bitmap Toolkit (pbm+) can be used for converting many FITS files to such a format. However, support is not guaranteed for all FITS files where the data are in the form of an image. In particular, there may be problems when the data matrix members are in IEEE floating point format (BITPIX<0) or the matrix has more than two dimensions (NAXIS>2). Archie Warnock and Ron Baalke have announced release of version 7.8 of the IMDISP program. IMDISP is an interactive image processing program that runs on an IBM PC computer and supports FITS input. IMDISP 7.8 is available via anonymous ftp at ames.arc.nasa.gov [128.102.18.3] in a file called imdisp78.zip in the pub/SPACE/SOFTWARE subdirectory and at hypatia.gsfc.nasa.gov in the pub/software/imdisp subdirectory. It is also available through Simtel-20 [192.88.110.20] at PD1:IMDISP78.ZIP. Additional discussion of FITS->image converters appears in this newsgroup from time to time. 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 transport 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, commissioned by NASA Headquarters, is maintained by the NASA/OSSA Office of Standards and Technology (NOST) FITS Support Office. This Guide is intended to be a tutorial for new FITS users. 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. A new version, 3.0, was issued in January 1993. This document is at present available only in printed form, but steps are under way to generate a PostScript version that will work on many systems and a flat ASCII version. Because of the large volume of copies of the new edition that are being sent out, there may be some delays in the response until the backlog is cleared. NASA is sponsoring development of a formal standard for FITS. The goal document codifying FITS as endorsed by the IAU, eliminating some contradictions and ambiguities in the original FITS papers, that can be endorsed by the IAU FITS Working Group as the FITS standard. The document is being developed by a Technical Panel chaired by Dr. Robert J. Hanisch (STSci), with review by the astronomical community. Only minor revisions are expected to the current draft, version 0.3b, but the form of the standard is not final, and it does not supersede the four papers and Floating Point Agreement endorsed by the IAU as the official standard for FITS. The IAU has endorsed the Floating Point Agreement, which defines how floating point numbers are to be expressed in FITS. The basic agreement appears verbatim in the User's Guide, and the substance is incorporated in the Draft NASA FITS definition. The NOST maintains a file of FITS information available by anonymous ftp from nssdca.gsfc.nasa.gov or DECnet copy from NSSDCA, in the directory FITS. It includes copies of the current NASA draft standard in flat ASCII, PostScript, and LaTeX. Style and index files are provided for the LaTeX form. A current list of the extension type (structure) names registered with the IAU FITS Working Group is maintained. Also available, in LaTeX form, is the text of the proposal for one of these new extension types, IMAGE. A README. file describes the contents of the directory. A SOFTWARE subdirectory, described by an included README.FIRST file, contains a program in C to read and list the headers of a FITS file and another file with information on publicly available FITS software packages. The ERRTEST subdirectory contains several versions of the same FITS file, a valid one and several with different kinds of header errors, for use in testing software to read FITS files. An included README.FIRST file contains details. Additional material can be obtained by anonymous ftp from the National Radio Astronomy Observatory, from fits.cv.nrao.edu, in the directory FITS. The Documents subdirectory (case is significant) contains copies of the BINTABLE Binary Tables extension proposal, which is now under consideration by the FITS committees, and a draft describing a suggested method for data compression under FITS. It also contains text of a paper summarizing conclusions of a workshop on World Coordinates held in Charlottesville in 1988, which is serving as the basis for continuing discussion of world coordinates issues, some of which appears on this newsgroup from time to time. These documents are available in both LaTeX and PostScript forms. A number of additional documents are available in ASCII text form, including the proposal on physical blocking of FITS files on media other than tape and material on FITS, its history, and the FITS community. Printed copies of many of the documents listed above can be obtained from the NOST Librarian. Printed copies of the User's Guide and either paper or electronic copies of the Draft NOST 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 NOST can be reached as follows: (Postal) NASA/OSSA Office of Standards and Technology Code 633.2 Goddard Space Flight Center Greenbelt MD 20771 USA (Internet) nost at nssdca.gsfc.nasa.gov (DECnet) NCF::NOST Telephone: (301)286-3575 8 a. m. - 5 p. m., U. S. Eastern Time If the Librarian is unavailable, a phone mail system takes the call after four rings. Please mention this posting in your request. Barry M. Schlesinger Coordinator, NASA/NSSDC NOST FITS Support Office (301) 513-1634 fits at nssdca.gsfc.nasa.gov NCF::FITS From fitsbits-request Sat Jan 23 15:22:06 1993 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["898" "Sat" "23" "January" "1993" "19:31:01" "GMT" "Brian Carey 283-4181" "careyb at pisces.jsc.nasa.gov " nil "25" "Celestron telescope for sale" "^From:" nil nil "1"]) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA03759; Sat, 23 Jan 93 15:22:06 EST Return-Path: Message-Id: <1993Jan23.193101.10130 at aio.jsc.nasa.gov> Organization: MDSSC Path: cv3.cv.nrao.edu!uvaarpa!concert!gatech!swrinde!zaphod.mps.ohio-state.edu!cs.utexas.edu!bcm!aio!pisces!careyb From: careyb at pisces.jsc.nasa.gov (Brian Carey 283-4181) Sender: fitsbits-request at fits.CV.NRAO.EDU To: fitsbits at fits.CV.NRAO.EDU Subject: Celestron telescope for sale Date: Sat, 23 Jan 1993 19:31:01 GMT For sale Celestron Super Polaris C6 Telescope Information of this Newtonian reflector telescope is: Diameter: 150 mm Focal Length: 750mm Near Focus with eyepiece: 8' with camera: 6' Highest Useful Power: 360x Resolution (arc seconds): 0.76 Light Gathering Power: 459 Limiting Visual Power: 13.4 f/ratio: f/5.0 Weight Optical Tube: 10.5 lb. With Tripod: 38 lb. The telescope comes with tripod, Equatorial Mount with polar axis finderscope, eye piece, top mounted spotting scope, and tripod center tray with container. All of the above for $550.00 OBO If interested email or call Brian C. Carey phone 488 - 6432 (home). From fitsbits-request Tue Jan 26 10:47:40 1993 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["7064" "Tue" "26" "January" "93" "10:49:30" "EST" "Eric Greisen" "egreisen at primate.CV.NRAO.EDU " nil "164" "Spherical coordinates in FITS" "^From:" nil nil "1"]) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA03653; Tue, 26 Jan 93 10:47:40 EST Return-Path: Message-Id: <9301261549.AA00403 at primate.cv.nrao.edu> From: egreisen at primate.CV.NRAO.EDU (Eric Greisen) Sender: fitsbits-request at fits.CV.NRAO.EDU To: fitsbits at fits.CV.NRAO.EDU Subject: Spherical coordinates in FITS Date: Tue, 26 Jan 93 10:49:30 EST At the request of Don Wells and others, I have been working with Mark Calabretta (Australia Telescope) on a relatively definitive discussion of celestial coordinates in FITS. I began by converting my old AIPS Memos No. 27 and 46 into modern postscript files. I did not release these to the FITS community since I expected that any new agreement might have some differences with them - and the draft document does have some semi-serious differences as well as a rather better understanding of the whole subject. That draft is nearly ready for comment and will be announced in this forum, along with the old AIPS Memos dressed up in modern postscript. During the course of this work I was also made aware of the text in Chapter 4 of the NOST FITS Reference Guide which directly reflects a draft of the Hanisch/Wells paper on "World Coordinate Systems" of which I had not been aware. That draft contains a set of formulae for determining the new CDi_j matrix from the old CDELTn and CROTAn. Unfortunately, those formulae - specifically the cross terms - are wrong. The correct formulae are CDi_i = Di cos(rho) CDj_j = Dj cos(rho) CDi_j = -Dj sin(rho) CDj_i = Di sin(rho) where i < j refers to the first of either longitude or latitude, j refers to the other, Dn = CDELTn, and rho = CROTAm where m is the latitude-like axis. Eric W. Greisen, Scientist National Radio Astronomy Observatory Charlottesville, VA