IRAF Newsletter -- Number 14 -- April 1998

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The SAO R&D Software Suite

For those of you who may not have heard ...

In September 1997, we made a minor public release (version 1.7.1) of the SAO R&D software tree containing, among other things, a new and improved version of SAOtng . We invite you to retrieve the software and use it for your astronomical analysis (and other?) needs.

This autumn release of the SAO R&D package contains a handful of bug fixes to SAOtng 1.7. An important fix was made to support raw array files on little-endian platforms. Support also was added so that SAOtng will run on frame buffers deeper than 8 bits/pixel (although SAOtng itself uses only 8-bits of colormap). Note that this new color support still requires that the X server configuration support PseudoColor visuals--unfortunately, this appears not to be the case with most Linux X servers configured to run in 16, 24, and 32 bits/pixel mode (where TrueColor alone is supported).

SAOtng is a new version of the popular SAOimage display program. It is a superset of the Ximtool program developed at NOAO for IRAF and as such, utilizes the NOAO widget server (included in this package). It also incorporates the X Public Access mechanism to allow external processes to access and control its data, GUI functions, and algorithms. SAOtng supports direct display of IRAF images and FITS images (and easily can support other file formats), multiple frame buffers, region/cursor manipulation, several scale algorithms, many colormaps, and easy communication with external analysis tasks. It is highly configurable and extensible to meet the evolving needs of the astronomical community.

To add `open software' functionality to programs such as SAOtng , we have developed the `X Public Access' mechanism (XPA). Built on top of the existing Xt selection interface, XPA allows an Xt program to define points of public access through which data and commands can be exchanged with external programs. Its simple programming and command-line interface is designed so that arbitrarily large amounts of data can be transferred to and from Xt programs using XPA. Also, the data associated with a given access point can be read and written simultaneously. XPA is the precursor to a more generalized message bus system that will be built as collaboration between SAO and NOAO.

The SAO R&D software has been built at SAO on the following platforms:

Sun Sparc

Solaris 2.5

OpenWindows 3.2

Sun Sparc

SunOs 4.1.3, 4.1.4



HP/UX B.10.20



IRIX 5.2, 5.3, 6.2


DEC Alpha

OSF1 4.0


Gateway P5-90

Slackware 2.0.18


We develop and run the software mainly on Suns, but some time has been spent with the other (borrowed) platforms, especially 64-bit Alphas. Ports to other systems should be relatively easy at this stage. If you do a port (or try to and have problems), please let us know.

We currently are working on an update to 1.7.1 to support IRAF V2.11. Other new features in this release include support for display of FITS image extensions and FITS binary tables (e.g., X-ray event files), and support for display of catalog objects. We plan to release this upgrade on June 1, 1998.

Please visit the SAO R&D Group Home Page for news, updates, and downloads:

NB: Users of IRAF V2.11 should access the WWW page:

to get V2.11-enabled updates of individual 1.7.1 SAO R&D programs that will be made available before the spring upgrade.

Much of this software was developed at SAO by the HEAD Software R&D group with the significant help of collaborators across the country. The work at SAO was performed in large part under grants from NASA's Applied Information System Research Program (NAGW-3913 and NAG5-3996), with support from the AXAF Science Center (NAS8-39073). SAOtng , ASSIST, and XPA are embodiments of an evolving software cooperation philosophy and practice we hope to bring to astronomy and other disciplines. They reflect our efforts to understand how software systems (and people) can act in concert without sacrificing their independence.

Eric Mandel for the SAO R&D Software Group

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IRAF Group, National Optical Astronomy Observatories, P.O. Box 26732, Tucson, AZ 85726, Phone: (520) 318-8160, FAX: (520) 318-8360, Email

Posted: 07May1998