From postage_stamp-request Wed Oct 5 11:58:00 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["2422" "Wed" " 5" "October" "1994" "11:57:11" "EDT" "Doug Mink" "mink@cfa165.harvard.edu" nil "46" "Charter for postage_stamp mailing list" "^From:" nil nil "10" nil nil (number " " mark " Doug Mink Oct 5 46/2422 " thread-indent "\"Charter for postage_stamp mailing list\"\n") nil] nil) 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: 14 Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA21476; Wed, 5 Oct 94 11:58:00 EDT Return-Path: Message-Id: <9410051557.AA03619@cfa165.harvard.edu.HARVARD.EDU> From: mink@cfa165.harvard.edu (Doug Mink) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: Charter for postage_stamp mailing list Date: Wed, 5 Oct 94 11:57:11 EDT Astronomical Data Postage Stamp Image Mailing List Welcome to the POSTAGE_STAMP mailing list. It originated at the 1994 ADASS meeting as a means for discussing standards and procedures for serving and viewing "postage stamp" images of an arbitrary portion of the sky. We want the mailing list to include everyone who has a large public image database. We expect to discuss standards for access, such as keywords and coordinate systems, and standards for provided products, such as compression and dealing with image overlaps and gaps. To avoid unnecessary duplication, work in progress as well as existing products should be discussed. GOALS Our first goal is to produce servers and client browsers to deal with simple single-wavelength images including World Coordinate System (WCS) sky position information. We also need client software which can be executed from within application programs, in order to compare survey catalogs, overlay information, or facilitate astrometric calibration of optical imagery. A major issue to discuss is the standardization of a compression method (or methods--that is an additional debate). Other tasks include finding ways to deliver multiple simultaneous wavelengths and overlays of catalogued data. It is hoped that any software which is produced be shared with the rest of the community. Incremental goals will be set, so that the large databases can be used as soon as possible. WHAT EXISTS NOW IPAC's 'ISSA Postage Stamp Service' currently serves 80x80-pixel WCS FITS images with a selected center from the IRAS Sky Survey Atlas at URL http://brando.ipac.caltech.edu:8888/ISSA-PS A more versatile Mosaic-based, multi-wavelength image server has been implemented by the NASA/Goddard SkyView program at URL http://skyview.gsfc.nasa.gov/skyview.html It also returns a FITS file with WCS information. There is no viewer which automatically displays FITS files with WCS. SAOimage can be used to display the images returned by SkyView, but it does not yet deal with WCS information. IPAC's Skyview (no capital V) program can deal with WCS, but needs a better browsing interface. The SAO Skymap program, described at URL http://tdc-www.harvard.edu/software/skymap.html has extensive overlay capabilities, but only a rudimentary image display. -Doug Mink (mink@cfa.harvard.edu) Telescope Data Center Smithsonian Astrophysical Observatory Cambridge, Massachusetts USA From postage_stamp-request Wed Oct 5 12:15:14 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1013" "Wed" " 5" "October" "1994" "12:14:26" "EDT" "Doug Mink" "mink@cfa165.harvard.edu" nil "20" "Postage stamp clients" "^From:" nil nil "10" nil nil (number " " mark " Doug Mink Oct 5 20/1013 " thread-indent "\"Postage stamp clients\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA21548; Wed, 5 Oct 94 12:15:14 EDT Return-Path: Message-Id: <9410051614.AA03665@cfa165.harvard.edu.HARVARD.EDU> From: mink@cfa165.harvard.edu (Doug Mink) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: Postage stamp clients Date: Wed, 5 Oct 94 12:14:26 EDT saoimage is currently usable as a display client for images returned by SkyView or the ISSA postage stamp server. Could someone who knows how to set this up post the procedure to the list? NRAO has a C library of World Coordinate System conversion routines. It is not quite ready to be released; when it is available, I propose, as a first step, to incorporate it into saoimage to provide sky position feedback in parallel to the image coordinate feedback already provided. The resulting modified program will be made available as soon as possible. Client-side coordinate grids can be added later. Through the grapevine I have heard that Mike van Hilst, author of saoimage but no longer at SAO, has begun updating the program for release by the Free Software Foundation as a public domain image display program. I will be in touch with him about including WCS in his new program. -Doug Mink (mink@cfa.harvard.edu) Telescope Data Center Harvard-Smithsonian Center for Astrophysics Cambridge, Massachusetts From postage_stamp-request Wed Oct 5 12:44:29 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["387" "Wed" " 5" "October" "1994" "12:44:14" "-0400" "Tom McGlynn" "MCGLYNN@GROSSC.GSFC.NASA.GOV" nil "15" "SkyView disk crash." "^From:" nil nil "10" nil nil (number " " mark " Tom McGlynn Oct 5 15/387 " thread-indent "\"SkyView disk crash.\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA21585; Wed, 5 Oct 94 12:44:29 EDT Return-Path: Message-Id: <941005124414.20200656@GROSSC.GSFC.NASA.GOV> From: Tom McGlynn Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Cc: MCGLYNN@GROSSC.GSFC.NASA.GOV Subject: SkyView disk crash. Date: Wed, 5 Oct 1994 12:44:14 -0400 (EDT) TWIMC, Anyone who may wish to try out the NASA Goddard SkyView program may want to know that we've just had our primary disk crash and so we're out of commission for a couple of days while we scamble to fix the disk or find new locations for our data. I'll send out an update when we come back on-line. Tom McGlynn Goddard Space Flight Center mcglynn@grossc.gsfc.nasa.gov From postage_stamp-request Wed Oct 5 14:15:53 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["3444" "Wed" " 5" "October" "1994" "11:14:02" "PDT" "dave@ipac.caltech.edu" "dave@ipac.caltech.edu" nil "56" "" "^From:" nil nil "10" nil nil (number " " mark " dave@ipac.caltech Oct 5 56/3444 " thread-indent "\"\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA21745; Wed, 5 Oct 94 14:15:53 EDT Return-Path: Message-Id: <9410051814.AA14556@brando.ipac.caltech.edu> From: dave@ipac.caltech.edu Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Date: Wed, 5 Oct 94 11:14:02 PDT The ISSA Postage Stamp Server at IPAC D. Van Buren, R. Ebert, D. Egret We'll give a brief description of our server. A more detailed version will appear in the AJ. Our design goal was to give users a simple interface to the ISSA so both casual browsing and more heavy-duty "survey" mode data gathering would be easy. An important principle was that we would provide the ISSA data with no further processing - this was to be a way to get at the released data, not a way to reformat, rebin, reproject etc. Those tasks are all better left to the user's software. Obviously, reformating, rebinning and reprojecting all change the data so it is no longer the ISSA data but something else. The second important principle was to design the server so that other programs could make a TCP/IP connection, make a request, and then get back enough information to pick up the fits images automatically. In this way we can support large surveys, interfaces from other programs etc. It turned out that it was simple just to implement the server as an html server and then remote programs only need to understand enough html to get the information they need. This way NCSA Mosaic is a convenient browsing interface. We only ship one size image - 2 degrees by 2 degrees. This is the largest image we can make that is guaranteed not to require mosaicking adjacent plates. Those who need larger images can ftp the entire plates from the on-line archive. When users dial in to http://brando.ipac.caltech.edu:8888/ISSA-PS they connect with a MOO server which supports a large number of interfaces to network data services, and allows synergistic interactions between them. The MOO server interprets the web request, formats it and dispatches it to the core postage stamp server (which does not speak html). If the request is by name, it first makes a position-by-name request to SIMBAD. The core server has several stages. It looks up the ISSA plate containing the requested field based on the coordinate. Then it snips out the four subimages corresponding to each of the four IRAS bands from the ISSA dataset on CDROM. These are placed in a local public ftp area. At the same time it converts each of these to a gif image for use by web browsers and places them in the ftp area as well. A list of created files is then sent back to the MOO server where an html document is created inlining the gifs and pointing to the fits files. The html is then sent to the user. An important part of the service is a "Read This!" section which lists caveats and other need-to-know items about the ISSA images. The postage stamp server query page has instructions how to configure NCSA Mosaic to retrieve fits files as binaries. For small requests users can click on the inlined images, but for large surveys they would likely find a survey engine easier to use. We have been playing around with this inside the MOO server, where one can currently edit a list of target names and get the ISSA postage stamps dumped on local disk. The service has been running since December 1993 and averages about ten requests a day. In the old days before ISSA, when we made "BigMaps" from the IRAS data almost by hand, it cost about 2 FTEs to service the same request rate. With the ramp down of IRAS activities at IPAC, the postage stamp server is the only way we can inexpensively make this data publicly available to all comers. From dwells Thu Oct 13 17:17:34 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["3182" "Thu" "13" "October" "1994" "17:17:29" "EDT" "Don Wells" "dwells@fits.CV.NRAO.EDU" nil "74" "worldpos.c -- WCS Algorithms from Classic AIPS" "^From:" nil nil "10" nil nil (number " " mark " Don Wells Oct 13 74/3182 " thread-indent "\"worldpos.c -- WCS Algorithms from Classic AIPS\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA21317; Thu, 13 Oct 94 17:17:34 EDT Return-Path: Message-Id: <9410132117.AA21308@fits.cv.nrao.edu> From: dwells@fits.CV.NRAO.EDU (Don Wells) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: worldpos.c -- WCS Algorithms from Classic AIPS Date: Thu, 13 Oct 94 17:17:29 EDT I am pleased to announce the availability of URL ftp://fits.cv.nrao.edu/fits/src/wcs/worldpos.tar.gz 16489 Oct 13 17:04 worldpos.tar.gz This is the code which was mentioned during the FITS-WCS BOF at ADASS'94. The tar file contains: tar tvf worldpos.tar rwxr-xr-x106/16 0 Oct 13 17:04 1994 worldpos/ rw-r--r--106/16 17535 Oct 13 16:01 1994 worldpos/worldpos.c rw-r--r--106/16 5143 Oct 13 16:23 1994 worldpos/testpos.c rw-r--r--106/16 2721 Oct 13 17:04 1994 worldpos/testpos.ref rw-r--r--106/16 25265 Oct 10 16:46 1994 worldpos/COPYING.LIB-2.0 rw-r--r--106/16 2277 Oct 13 16:31 1994 worldpos/Makefile I append selected text from file worldpos.c. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- /* worldpos.c -- WCS Algorithms from Classic AIPS. Copyright (C) 1994 Associated Universities, Inc. Washington DC, USA. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License.. These two ANSI C functions, worldpos() and xypix(), perform forward and reverse WCS computations for 8 types of projective geometries ("-SIN", "-TAN", "-ARC", "-NCP", "-GLS", "-MER", "-AIT" and "-STG"): worldpos() converts from pixel location to RA,Dec xypix() converts from RA,Dec to pixel location where "(RA,Dec)" are more generically (long,lat). These functions are based on the WCS implementation of Classic AIPS, an implementation which has been in production use for more than ten years. See the two memos by Eric Greisen ftp://fits.cv.nrao.edu/fits/documents/wcs/aips27.ps.Z ftp://fits.cv.nrao.edu/fits/documents/wcs/aips46.ps.Z for descriptions of the 8 projective geometries and the algorithms. Footnotes in these two documents describe the differences between these algorithms and the 1993-94 WCS draft proposal (see URL below). In particular, these algorithms support ordinary field rotation, but not skew geometries (CD or PC matrix cases). Also, the MER and AIT algorithms work correctly only for CRVALi=(0,0). Users should note that GLS projections with yref!=0 will behave differently in this code than in the draft WCS proposal. The NCP projection is now obsolete (it is a special case of SIN). WCS syntax and semantics for various advanced features is discussed in the draft WCS proposal by Greisen and Calabretta at: ftp://fits.cv.nrao.edu/fits/documents/wcs/wcs.all.ps.Z ... int worldpos(double xpix, double ypix, double xref, double yref, double xrefpix, double yrefpix, double xinc, double yinc, double rot, char *type, double *xpos, double *ypos) ... int xypix(double xpos, double ypos, double xref, double yref, double xrefpix, double yrefpix, double xinc, double yinc, double rot, char *type, double *xpix, double *ypix) ... 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 From postage_stamp-request Fri Oct 14 15:32:22 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["360" "Fri" "14" "October" "1994" "15:31:29" "EDT" "Doug Mink" "mink@cfa165.harvard.edu" nil "8" "Client problems" "^From:" nil nil "10" nil nil (number " " mark " Doug Mink Oct 14 8/360 " thread-indent "\"Client problems\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA24538; Fri, 14 Oct 94 15:32:22 EDT Return-Path: Message-Id: <9410141931.AA05924@cfa165.harvard.edu.HARVARD.EDU> From: mink@cfa165.harvard.edu (Doug Mink) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: Client problems Date: Fri, 14 Oct 94 15:31:29 EDT I'm trying to use saoimage as a browser for SkyView-served images. The mime files seem to bet up appropriately. ftp:-served or local FITS files, when accessed through Mosaic, come up in saoimage, but when I try to get FITS files from an HTTP server, they appear as text files in the Mosaic window. Does anyone have any idea what I should change? -Doug Mink From postage_stamp-request Fri Oct 14 19:36:43 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["2256" "Fri" "14" "October" "1994" "19:35:53" "EDT" "Doug Mink" "mink@cfa165.harvard.edu" nil "56" "Re: Client problems" "^From:" nil nil "10" nil nil (number " " mark " Doug Mink Oct 14 56/2256 " thread-indent "\"Re: Client problems\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA25018; Fri, 14 Oct 94 19:36:43 EDT Return-Path: Message-Id: <9410142335.AA06574@cfa165.harvard.edu.HARVARD.EDU> From: mink@cfa165.harvard.edu (Doug Mink) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: Re: Client problems Date: Fri, 14 Oct 94 19:35:53 EDT I asked my local WWW guru for assistance with my FITS/saoimage problem, and he responded with a fix which worked, so I forward it to the list. -Doug Mink > To: mink@cfa165.HARVARD.EDU (Doug Mink) > Subject: Re: Client problems with FITS > Date: Fri, 14 Oct 1994 17:44:46 -0400 > From: Alberto Accomazzi > > In message <9410141824.AA05834@cfa165.harvard.edu.HARVARD.EDU>, Doug Mink > writes: > > > Alberto, > > This should probably be "HTTP and FITS files". When I use Mosaic to acces > > a FITS file as a local file or using FTP, SAOIMAGE pops up as a browser, > > but when I access an identical file, with a .fits extension, using HTML, > > Mosaic tries to display it as a text file. Do you know how to fix this? > > It's a problem of MIME-typing. When Mosaic gets something from an > HTTP server, it is the server's responsibility to tell the browser > what is being returned. Obviously HTTP does not know about > image/x-fits, so it gives up. I believe that NCSA HTTP 1.3 lets you > add some mime types. You should check the documentation online. > I know that adding this to srm.conf works for compressed files: > > # AddEncoding allows you to have certain browsers (Mosaic/X 2.1+) uncompress > # information on the fly. Note: Not all browsers support this. > AddEncoding x-compress Z > AddEncoding x-gzip gz > > > Another solution is using a CGI script that always returns a > Content-type: image/x-fits > to retrieve FITS files (it is kind of a kludge but should work). > Good luck and let me know what you come up with. > > - Alberto > > Date: Fri, 14 Oct 94 19:25:50 EDT > From: mink (Doug Mink) > To: alberto@cfa0 > Subject: Re: Client problems with FITS > > Alberto, > I updated my httpd to version 1.3 and added the following line to srm.conf > > AddType image/x-fits .fit .fits .fts .FIT .FITS > > the restarted httpd. saoimage now pops up with the html-requested image. > I have suggested to the SkyView people at Goddard that they do the same. > Apparently IPAC's system already does the right thing. Now all I have to > do is add WCS awareness to saoimage, a task for which I now have the > libraries. I hope to have everything working by next Thursday's lunch > talk. > -Doug From postage_stamp-request Fri Oct 14 19:41:21 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["493" "Fri" "14" "October" "1994" "19:40:32" "EDT" "Doug Mink" "mink@cfa165.harvard.edu" nil "14" "WWW Introduction to image serving" "^From:" nil nil "10" nil nil (number " " mark " Doug Mink Oct 14 14/493 " thread-indent "\"WWW Introduction to image serving\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA25039; Fri, 14 Oct 94 19:41:21 EDT Return-Path: Message-Id: <9410142340.AA06588@cfa165.harvard.edu.HARVARD.EDU> From: mink@cfa165.harvard.edu (Doug Mink) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: WWW Introduction to image serving Date: Fri, 14 Oct 94 19:40:32 EDT I have a hypertext version of my charter to the postage_stamp list, including a multiply-sorted archive of all postings which I will endeavor to keep current. It is available at URL httpd://tdc-www.harvard.edu/Postage_stamp/postage_stamp.html A FITS copy of IRAF's M51 test image with WCS information, httpd://tdc-www.harvard.edu/Postage_stamp/wpix.fits is accessible through it for testing. I have the NRAO WCS library and hope to have a WCS-aware saoimage early next week. -Doug Mink From postage_stamp-request Fri Oct 14 19:58:04 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["489" "Fri" "14" "October" "1994" "19:57:15" "EDT" "Doug Mink" "mink@cfa165.harvard.edu" nil "10" "WWW Image Serving Intro (corrected)" "^From:" nil nil "10" nil nil (number " " mark " Doug Mink Oct 14 10/489 " thread-indent "\"WWW Image Serving Intro (corrected)\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA25059; Fri, 14 Oct 94 19:58:04 EDT Return-Path: Message-Id: <9410142357.AA06674@cfa165.harvard.edu.HARVARD.EDU> From: mink@cfa165.harvard.edu (Doug Mink) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: WWW Image Serving Intro (corrected) Date: Fri, 14 Oct 94 19:57:15 EDT I have a hypertext version of my charter to the postage_stamp list, including a multiply-sorted archive of all postings which I will endeavor to keep current. It is available at URL http://tdc-www.harvard.edu/Postage_stamp/postage_stamp.html A FITS copy of IRAF's M51 test image with WCS information, URL http://tdc-www.harvard.edu/Postage_stamp/wpix.fits is accessible through it for testing. I have the NRAO WCS library and hope to have a WCS-aware saoimage early next week. -Doug Mink From postage_stamp-request Fri Oct 14 20:06:22 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["320" "Fri" "14" "October" "1994" "20:05:31" "EDT" "Doug Mink" "mink@cfa165.harvard.edu" nil "12" "Setting up a FITS client" "^From:" nil nil "10" nil nil (number " " mark " Doug Mink Oct 14 12/320 " thread-indent "\"Setting up a FITS client\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA25076; Fri, 14 Oct 94 20:06:22 EDT Return-Path: Message-Id: <9410150005.AA06692@cfa165.harvard.edu.HARVARD.EDU> From: mink@cfa165.harvard.edu (Doug Mink) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: Setting up a FITS client Date: Fri, 14 Oct 94 20:05:31 EDT To use saoimage as a client to display FITS images served by IPAC or SkyView, add the following line to Mosaic's mime.types file image/x-fits fit fits fts FIT FITS and the following line to Mosaic's mailcap file image/x-fits; saoimage -fits %s -Doug Mink Harvard-Smithsonian Center for Astrophysics From postage_stamp-request Fri Oct 21 16:35:22 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["4948" "Fri" "21" "October" "1994" "16:35:05" "-0400" "Tom McGlynn" "MCGLYNN@GROSSC.GSFC.NASA.GOV" nil "105" "Best" "^From:" nil nil "10" nil nil (number " " mark " Tom McGlynn Oct 21 105/4948 " thread-indent "\"Best\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA13742; Fri, 21 Oct 94 16:35:22 EDT Return-Path: Message-Id: <941021163505.20c00147@GROSSC.GSFC.NASA.GOV> From: Tom McGlynn Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Cc: MCGLYNN@GROSSC.GSFC.NASA.GOV Subject: Best Date: Fri, 21 Oct 1994 16:35:05 -0400 (EDT) SkyView support for postage stamp services. I had hoped to send something to this mailing list earlier. The disk crash we have just recovered from, and a personal crash due to bronchitis and pneumonia have slowed us down a bit. Introduction to SkyView. Since the IPAC group has already given a nice intro to their system let me just say a paragraph or two about our SkyView. The purpose of SkyView is to provide a single interface by which astronomers can get data in any useful coordinate system or projection. SkyView keeps copies of the data on-line on jukeboxes and dynamically reformats the data to fit the user's request. There are some reasonably nice things one can do with the images in the interactive interface, but the purpose is primarily image generation, not image display or manipulation. The holdings currently include the compressed optical Southern Sky Survey as distributed by ST ScI, 3 radio surveys, the IRAS Sky Atlas, the preliminary EUVE data, a mosaic of all public ROSAT images (due to be much improved in the next month), the HEAO 1 A2 survey, and the EGRET gamma-ray survey. A user can, e.g., specify a point in the southern sky and SkyView will automatically generate a image in a standard coordinate system from the Southern Sky Survey, eliminating the rotations and distortions of the Schmidt plates. In this case, since the survey is undersampled, there may be occasional distortions of up to a pixel of individual objects (since a nearest neighbor algorithm is used). Images are typically returned within a minute of the request. Images from multiple surveys can be requested at the same time. The actual process is to first determine the coordinates of each pixel in the user's image in the user's coordinate system and then transform each of these coordinates to the native coordinate system of the survey being sampled. These values are then projected using the same projection as the survey. If the survey involves a number of submaps, then this is done separately for each submap as needed. This gives up the central pixel location for each of the user's pixels in terms of the survey data. The survey is then resampled (using nearest neighbor for the Mosaic interface, some more sophisticated possibilities are available in the interactive interface) at the these points and the user's image is returned. In the Web version, the image is returned as a GIF on a page with some descriptive information and pointers to more detailed information. An anchor allows the user to retrieve the FITS file. SkyView is not intended for users who need to take a survey to its limit. Rather the intent is let users get pretty good answers very quickly. SkyView and direct postage stamp access. Currently SkyView returns a page to the user with an image and context information included. Links to the FITS file allow a user to retrieve it directly. We shall try to implement Doug Mink's suggestions for making retrieval of the FITS files by users more convenient. During the ADASS meeting in discussions with Joe Pollizzi and Don Wells it became clear that we could make SkyView work as client for software as well as for humans. In the next week or so we will also provide a URL which will directly return the FITS file when it receives a properly formatted request. Since the HTTP daemon simply receives an encoded message of the form: keyword=value&keyword=value&... we can easily adapt our system to return a unencumbered FITS file when it receives the appropriate string. A program which needs a FITS file then will need only to send an appropriately formatted string to our HTTP server and a FITS file will be returned directly. Currently some the keywords our server expects are: VCOORD The coordinate (or object name) string MAPROJ (values: Gnomonic, Rectangular, Hammer-Aitoff and Orthographic) SCOORD Equatorial, Galactic, and Ecliptic EQUINX Equinox of image SFACTR Size of image in degrees SURVEY Requested survey CATLOG Requested catalogs to overlay ISCALN Image scaling (Linear, Log10, or Hist.Eq.) GRIDDD Provide grid PIXELX Number of pixels in X directory PIXELY Number of pixels in Y SMOOTH Size of boxcar to smooth image. These choices were not made for compatibility with anything, so they aren't particularly obvious. However if we are to provide these kinds of servers, it behooves us to think about what the standard keywords will be (and what the legal values will be). Where appropriate the FITS keywords might be used, but this is long term issue. In the shorter term, we shall add another keyword, RTFITS, which says return the FITS file directly without all of the ancillary data. Using our HTTP server, SkyView can then serve client software as well as users. We would be very interested in comments by users about how SkyView might better serve their needs. Tom McGlynn Goddard Space Flight Center mcglynn@grossc.gsfc.nasa.gov From postage_stamp-request Fri Oct 21 16:37:03 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["2" "Fri" "21" "October" "1994" "16:36:51" "-0400" "Tom McGlynn" "MCGLYNN@GROSSC.GSFC.NASA.GOV" nil "2" "Previous message should be named:Using SkyView as a Postage Stamp server" "^From:" nil nil "10" nil nil (number " " mark " Tom McGlynn Oct 21 2/2 " thread-indent "\"Previous message should be named:Using SkyView as a Postage Stamp server\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA13760; Fri, 21 Oct 94 16:37:03 EDT Return-Path: Message-Id: <941021163651.20c00147@GROSSC.GSFC.NASA.GOV> From: Tom McGlynn Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Cc: MCGLYNN@GROSSC.GSFC.NASA.GOV Subject: Previous message should be named:Using SkyView as a Postage Stamp server Date: Fri, 21 Oct 1994 16:36:51 -0400 (EDT) From postage_stamp-request Thu Oct 27 17:09:03 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["1440" "Thu" "27" "October" "1994" "17:08:09" "EDT" "Doug Mink" "mink@cfa165.harvard.edu" nil "32" "Postage stamp client available" "^From:" nil nil "10" nil nil (number " " mark " Doug Mink Oct 27 32/1440 " thread-indent "\"Postage stamp client available\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA12984; Thu, 27 Oct 94 17:09:03 EDT Return-Path: Message-Id: <9410272108.AA25070@cfa165.harvard.edu.HARVARD.EDU> From: mink@cfa165.harvard.edu (Doug Mink) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: Postage stamp client available Date: Thu, 27 Oct 94 17:08:09 EDT I have modified saoimage to use the NRAO world coordinate system subroutines. It can track the cursor in world coordinates as well as image coordinates and execute an external command using an internally generated world coordinate string. It is not debugged on systems other than SunOS 4.1.3 yet, but I am working on getting versions running on Decstation Ultrix and Solaris. The SunOS executable is available for anonymous ftp as /pub/gsc/Saoimage/saoimage1.09.sunos.Z on cfa0.harvard.edu The 'c' command prints the cursor world coordinate position to stdout, and the 'w' command executes the command set by -wcscom using the world coordinates of the cursor's current position. My Guide Star Catalog search program, rgsc, has been updated to work with the world coordinate string produced by saoimage. It is available on the same machine as /pub/gsc/Rgsc/rgsc2.6.sunos.tar.Z. RGSC documentation is also available on the World-Wide Web at URL http://tdc-www.harvard.edu/software/rgsc.html To use rgsc with saoimage, put it in your search path, set up the parameter file with the appropriate CDROM pathnames in your working directory, and run saoimage -wcscom rgsc_append=yes_dbox=.01_%s I hope to add to the documentation for both saoimage and rgsc to document use of the programs in this manner. -Doug Mink Telescope Data Center Harvard-Smithsonian Center for Astrophysics Cambridge, Massachusetts, USA From postage_stamp-request Fri Oct 28 18:09:38 1994 Status: RO X-VM-v5-Data: ([nil nil nil nil nil nil nil nil nil] ["183" "Fri" "28" "October" "1994" "18:08:38" "EDT" "Doug Mink" "mink@cfa165.harvard.edu" nil "7" "Ultrix postage stamp client available" "^From:" nil nil "10" nil nil (number " " mark " Doug Mink Oct 28 7/183 " thread-indent "\"Ultrix postage stamp client available\"\n") nil] nil) Received: by fits.cv.nrao.edu (4.1/DDN-DLB/1.5) id AA16719; Fri, 28 Oct 94 18:09:38 EDT Return-Path: Message-Id: <9410282208.AA26220@cfa165.harvard.edu.HARVARD.EDU> From: mink@cfa165.harvard.edu (Doug Mink) Sender: postage_stamp-request@fits.CV.NRAO.EDU To: postage_stamp@NRAO.EDU Subject: Ultrix postage stamp client available Date: Fri, 28 Oct 94 18:08:38 EDT There is a binary copy of saoimage 1.09 for Decstation Ultrix at URL ftp://cfa0.harvard.edu/pub/gsc/Saoimage/saoimage1.09.dec.Z Solaris and alpha ports are coming. -Doug Mink