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NOAO Newsletter - Observational Programs - June 2000 - Number 62


IRAF Update

Doug Tody

As we write this, May 2000 is only several days away and the end of an era is rapidly approaching. Jeannette Barnes is retiring in May after nearly 40 years at KPNO and later NOAO, and after a 20-year association with the IRAF project. Literally hundreds of astronomers around the world know Jeannette and will remember the enthusiasm and hard work that she has given to astronomy over the years. We will miss her and the motivation and leadership she has provided to NOAO and IRAF these many years.

While the next patch release of IRAF is not expected until next summer, a number of recent application updates and enhancements have extended the capability of the current release of IRAF. Among the updates detailed below are a new version of X11IRF tools (XGterm, XImtool, etc.), the execution of IRAF scripts at the host level, the initial release of the IRAF astrometry package, and a new "charge shuffling" mode for the ICE CCD data acquisition package.

The current release of IRAF is V2.11.3, which was updated for all supported IRAF platforms in late 1999. No further patch releases are expected until perhaps summer 2000. Preliminary tests on a Solaris8 system here at NOAO indicate that the current Sun/IRAF release is compatible with Solaris 8, although we have not yet run extensive tests. The current RedHat Linux release, version 6.2, also appears to be reasonably compatible.

The new version of the X11IRAF tools (XGterm, XImtool, etc.) has been completed and is currently undergoing final testing. This version, which should be released for all supported IRAF platforms in early May, is primarily a bug-fix release to support the IRAF science GUIs and to improve the stability of XGterm during extended use. Most changes will be transparent to users, but a few new features were added. XImtool now allows the hardcopy image annotation to be more customizable, various new keystroke accelerators were added to XImtool, XGterm was updated to be based on X11R6, and the Client Display Library (CDL) is now part of the X11IRAF distribution (a separate distribution will continue to be available). The Object Manager GUI toolkit now contains a new Tabs widget and 3-D Scrollbar, and the entire package was updated to support new platforms such as Intel Solaris 7, LinuxPPC, and the new Linux glibc libraries. The new version of X11IRAF is available from our FTP archives at iraf.noao.edu in the /iraf/x11iraf directory.

A new IRAF capability introduced with the release of IRAF V2.11.2 allows IRAF scripts to be executed as host level commands (an Open IRAF feature). Users who have questions about how to use and implement this new facility should check our Web page for further details (see http://iraf.noao.edu/iraf/web/new_stuff/cl_host.html/).

The initial version of the IRAF astrometry package is now in the final stages of testing and documentation, in preparation for formal release later this year. This package includes a general-purpose astrometric catalog extraction and filtering task, and a related image survey image extraction task. A network-based catalog access interface developed earlier is used in this application. Code developed for the catalog extraction and filtering task was successfully used in the new NOAO on-line proposal system to extract Gemini guide stars.

As part of our work to support Gemini reductions--and generally enhance the IRAF reduction packages--Frank Valdes has identified the information needed to describe spectroscopic data in two-dimensional image formats. This includes most of the new multiplexed formats such as multifiber, slit masks, and IFUs. The description is intended to allow software, such as the tasks in the IRAF APEXTRACT package, to automatically locate and extract the often large numbers of spectra. The information can also be used to reconstruct data cubes for IFUs. The analysis may be found at http://iraf.noao.edu/projects/ccdmosaic/imagedef/spec2d.html. These conventions are still under development, and review and comments are welcome.

The IRAF group is working with the NOAO Deep Wide-Field Survey team to further develop the software used to pipeline process the survey data. While the primary goal of this effort is to help process the data for the survey, the experience gained in carrying out an actual survey project will be very worthwhile, given the increasing importance of surveys in ground-based astronomy, including a number of programs currently underway or planned involving the NOAO telescopes. The effort will also result in new capabilities and tasks for processing multi-band optical and IR data in IRAF. Valdes and Davis are both involved in the effort at this stage, which is concentrating on reduction of the OIR image data. In later phases of the project, we will look at catalog generation and at how to make the data products available online on the Internet.

Rob Seaman has prepared a version of the ICE CCD data acquisition package to support a new "charge shuffling" dual-exposure mode for spectral imaging at Kitt Peak National Observatory. Charge shuffling involves repeatedly shifting the charge back and forth from side to side of a CCD, while nodding the telescope alternately from an object to a blank sky position. The CCD is optically masked such that the sky pixels are kept dark, while the object pixels are exposed and vice versa. The nodding and shuffling and opening and closing of the camera shutter occurs on a short enough time scale that the sky brightness variations are frozen.

The output of this process is a dual exposure of contemporaneous object and sky spectra accumulated through the exact same optical path. This mode is beneficial, for instance, for multi-slitlet observations such that the width of each slitlet can be minimized to allow many more slits per exposure. New parameters added to ICE include the number of nods and the number of pixels to shift for each exposure. A variety of different nodding patterns are supported, such as a simple ABAB object/sky pattern and a bracketed pattern that begins and ends with a half-length sky subexposure. The on-object and on-sky exposure times may be specified separately. Work continues on the header keyword definitions and data reduction software to support the new exposure type.

The tenth annual conference on Astronomical Data Analysis Software and Systems (ADASS) will be held at the Swissotel Boston, on 12-15 November 2000, and will be hosted by the Smithsonian Astrophysical Observatory. The ADASS Conference Series provides a forum for scientists and computer specialists concerned with algorithms, software, and operating systems that deal with the acquisition, reduction, and analysis of astronomical data. The program includes invited talks, contributed papers, display sessions, and computer demonstrations, as well as user group meetings and special interest meetings ("BOFs"). These activities aim to encourage communication between software specialists and users, and also to stimulate further development of astronomical software and systems. For further details see the ADASS X Web page at http://hea-www.harvard.edu/ADASS/.

For further information about the IRAF project, please see the IRAF Web pages at http://iraf.noao.edu/ or send e-mail to iraf@noao.edu. The 'adass.iraf' newsgroups (available on USENET or via a moderated mailing list to which you can subscribe by filling out a form on the IRAF Web page) provide timely information on IRAF developments and are available for the discussion of IRAF-related issues.


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