European Southern Observatory - MIDAS + SKYCAT

K. Banse, M. Albrecht (ESO)

The latest version of On-line Midas as used for ESO's Dataflow System will be shown. The Archive group will demonstrate SKYCAT, the catalog display tool which is based on ESO's Real Time Display (RTD).

P.S. Also, the 96NOV Midas CD-ROM should be ready.

Invited talk

Parkes Multibeam realtime object-oriented data reduction using AIPS++

D. Barnes (University of Melbourne), L. Staveley- Smith, T. Ye, T. Oosterloo (Australia Telescope National Facility (ATNF))

We present algorithms and their implementation details for the Australia Telescope National Facility (ATNF) Parkes Multibeam Software. The new thirteen-beam Parkes 21 cm Multibeam Receiver is being used for the neutral hydrogen (HI) Parkes All Sky Survey (HIPASS). This survey will search the entire southern sky for neutral hydrogen in the redshift range -1200 km/s to +12600 km/s; with a limiting column density of approximately 5 x 10^{17} atoms per square centimetre. Observations for the survey began late in February, 1997, and will continue through to the year 2000.

A complete reduction package for the HIPASS survey data has been developed, based on the AIPS++ library. The major software component is realtime, and uses advanced inter-process communication coupled to a graphical user interface (GUI), provided by AIPS++, to apply bandpass removal, flux calibration, velocity frame conversion and spectral smoothing to 26 spectra of 1024 channels each, every five seconds. AIPS++ connections have been added to ATNF-developed visualization software to provide on-line visual monitoring of the data quality. The non-realtime component of the software is responsible for gridding the spectra into position-velocity cubes; typically 200000 spectra are gridded into an 8 x 8 degree cube.

Parallel tree N-body code: data distribution and DLB on CRAY T3D for large simulations

U. Becciani, V. Antonuccio-Delogu (Obs. Catania), G. Erbacci (CINECA), R. Ansaloni (Silicon Graphics Italy), M. Gambera (Obs. Catania), A. Pagliaro (Inst. Astr. Catania)

During the last 3 years we have developed an N-Body code to study the origin and the evolution of the Large Scale Structure of the Universe (Becciani et al. 1996, 1997). The code, based on the Barnes-Hut tree algorithm, has been developed under the CRAFT environment to share work and data among the PEs involved in the run. The main purpose of this work was the study of the optimal data distribution in the T3D memory, and a strategy for the Dynamic Load Balance in order to obtain good performances when runnig the simulation with more than 10 million particles. To maximize the number of particles per second, updated at each step, we studied the optimal data distribution and the criterion to choose the PE executing the force computing phase and to reduce the load unbalancing. The results of our tests show that the step duration depends on two main factors: the data locality and the T3D network contention. Increasing data locality we are able to minimize the step duration. In a very large simulation, due to network contention, an unbalanced load arises. The DLB consists in implementing an automatic structure: each PE executes the force compute phase only for a fixed portion N of all the bodies residing in the local memory. The computation of all the remaining bodies is shared among all the PEs. The obtained results show that, fixing the PEs and the particles number, the same N value gives the best performance both in uniform and clustered condition. This means that it's possible to fix this quantity which can be usefully adopted during the running time without introducing any significant overhead to obtain a good Dynamic Load Balance.

Teaching Astronomy via the Internet

L. Benacchio, M. Brolis (Padova Astronomical Observatory), I. Saviane (Padova Department of Astronomy)

A project is being carried on at the Padova Astronomical Observatory, with the partnership of the Italian Telecom, whose aim is to supply high quality multimedia educational material and tools to public schools (14-18 teen) via the Internet. A WWW server has been set up, and in the early experimental phase, a number of schools in the city area will be connected to the Observatory and hence to the Internet. Teachers and students will use it for the annual course (1997/98)in astronomy.

Our purpose is to remove a lack in the Astronomical WWW sites currently active, i.e., by providing a carefully designed server which will deliver reliable information in a structured way and, at the same time, take full advantage of the medium. Apparently there are no sites devoted to the explanation of the basic astronomy and astrophysics, at the middle school level.

Our educational approach is based on the so-called Karplus cycle, that is: introduction of new concepts by means of proposed experiments, discussion and selection of the discovered laws and 'correct' explanation of the observations and application to new situations. To avoid the subject will try to `fit` the new knowledge into his/her already existing wrong schemes, a preliminary phase for the removal of existing misconceptions is present. In turn, the knowledge is introduced according to a hierarchical order of concepts.

The medium involved allows the full exploitation of this approach, since it permits direct experimentation by means of animation, java applets, and personalized answers to the proposed questions. Also, automatic tests and evaluations can be straightforwardly implemented. In this respect, it has a clear advantage over the traditional static book. Finally, the user can choose his/her own pace and path through the material offered.

We also propose a number of hands-on activities which extend and reinforce the concepts, and which require the presence of the teacher as an active guide.

Demonstration of Starlink Software

M. Bly, R. Warren-Smith (Rutherford Appleton Laboratory)

We will demonstrate the latest Starlink applications which will be available on the late summer Starlink CD-ROM release. The highlights include FIGARO with handling of error data, the GAIA GUI , an enhanced CURSA (catalogue access) and FIGARO running from the IRAF CL. Applications using the NDF data library will be able to work with non-NDF (eg IRAF) data formats using on-the-fly data conversion.

The demo needs:

SUN Ultra model 140 workstation or higher, with 8-bit colour TGX graphics (or equivalent) 128Mb memory 4Gb disk (2Gb to be available for software and data) 20-inch colour display 4x or better CD-ROM drive Solaris 2.5 operating system with CDE (Common Desktop Environment) Sparc Compiler 4.2: Fortran 77, C and C++ Internet connection if available.

Invited talk:

CyberHype or Educational Technology - What is being learned from all those BITS?

C. Christian

I will discuss various information technology methods being applied to science education and public information. Of interest to the group at STScI and our collaborators is how science data can be mediated to the non-specialist client/user. In addition, I will draw attention to interactive and/or multimedia tools being used in astrophysics that may be useful, with modification, for educational purposes. In some cases, straightforward design decisions early on can improve the wide applicability of the interactive tool.

Demonstration of AIPS++

T. Cornwell, B. Glendenning (NRAO), J. Noordam (NFRA)

AIPS++ is a package for radio-astronomical data reduction now under development by a consortium of radio observatories. It is currently in beta release and it expected to be publicly released in late 1997.

Description of demo:

We will demonstrate the beta version of AIPS++. This will consist of a demonstration by an AIPS++ Project Member at regularly scheduled times. In addition, we will make the system available for use by others.

Fitting and Modeling of the AXAF Data with the ASC Fitting Application

S. Doe, A. Siemiginowska, M. Ljungberg, W. Joye (SAO)

The AXAF mission will provide X-ray data with unprecedented spatial and spectral resolution. Because of the high quality of these data, the AXAF Science Center will provide a new data analysis system - part of which includes a new fitting application. Our intent is enable users to do fitting that is too awkward with or beyond the scope of existing astronomical fitting software. Our main goals are: 1) to take advantage of the full capabilities of the AXAF, we intend to provide a more sophisticated modeling capability (i.e., models that are f(x,y,E,t), models to simulate the response of AXAF instruments, and models that enable "joint-mode" fitting, i.e., combined spatial-spectral or spectral-temporal fitting); and 2) to provide users with a wide variety of models, optimization methods, and fit statistics. In this paper, we discuss the use of an object- oriented approach in our implementation, the current features of the fitting application, and the features scheduled to be added in the coming year of development. Current features include: an interactive, command-line interface; a modeling language, which allows users to build models from arithmetic combinations of base functions; a suite of optimization and fit statistics; the ability to perform fits to multiple data sets simultaneously; and, an interface with SM and SAOtng to plot or image data, models, and/or residuals from a fit. We currently provide a modeling capability in one or two dimensions, and have recently made an effort to perform spectral fitting in a manner similar to XSPEC. We also allow users to dynamically link the fitting application to algorithms written by users. Our goals for the coming year include: incorporating the XSPEC model library as a subset of models available in the application; enabling "joint-mode" analysis; and adding support for new algorithms.

J.R. Fisher (NRAO)

The Green Bank Telescope Monitor and Control software group adopted object-oriented design techniques as implemented in C++. The experience has been generally positive, but there certainly have been many lessons learned in the process. The long analysis phase of the OO approach has lead to a fairly coherent software system and a lot of module (class) reuse. Many devices (front-ends, spectrometers, LO's, etc.) share the same software structure, and implementing new devices in the latter part of the project has been relatively easy, as is to be hoped with an OO design. One disadvantage of a long design phase is that it is hard to evaluate progress and to have much sense for how the design satisfies the real user needs. In retrospect, the project might have been divided into smaller units with tangible products at early and mid stages of the project. The OO process is only as good at the requirement specifications, and the process has had to deal with continually emerging requirements all though the analysis, design, and implementation phases. Changes and fixes to core software modules have not been too painful, but they do require a robust software version control system. Large and medium scale test of the system in the midst of the implementation phase has required quite a bit of time and coordination effort. This has tended to inhibit progress evaluations.

News on the ISOPHOT Interactive Analysis (PIA)

C. Gabriel (ESA-SSD)

The ISOPHOT Interactive Analysis system, a calibration and scientific analysis tool for the ISOPHOT instrument on board ESA's Infrared Space Observatory (ISO), has been further developed while ISO is under operations.

After 18 months of ISO operations considerable experience has been achieved by the use of PIA, which led to several new features in the package. This experience has been achieved not only by the ISOPHOT Instrument Dedicated Team in its tasks of e.g. calibration, instrument performance check and refinement of analysis techniques, but also by a large number of ISOPHOT observers in around 100 astronomical institutes all over the world. PIA is distributed freely since longer than one year to all astronomers wishing to use it for ISOPHOT data reduction and analysis. The feedback from the different users is reflected not only in the extension of the analysis capabilities but also on a more friendly graphical interface, a better documentation, an easier installation. So became PIA not only a very powerful calibration tool but also the software tool of choice for the scientific analysis of ISOPHOT data.

In this paper we will concentrate on some of the PIA enhancements, by the scientific analysis, by the documentation and by the related general service to the astronomical community.

Distributed Searching of Astronomical Databases with Pizazz

K. Gamiel (National Computational Science Alliance/Univ. of IL)

The NCSA Pizazz SDK is an information retrieval communications toolkit that includes code and applications for for easily integrating existing database systems into a globally accessible, open standards-based system. The toolkit includes a TCP- based server and information retrieval protocol engine that handles all network communication between client and server. The server is designed as a drop-in application, extending the functionality of legacy database systems and creating a global infrastructure of astronomical database resources. The toolkit uses the Z39.50 information retrieval protocol.

M. Giuliano (STScI)

Operations of the Hubble Space Telescope (HST) require the creation of stable and efficient observation schedules in an environment where inputs to the plan can change daily. Operations must allow observers to adjust observation parameters after submitting the proposal. PIs must also be informed well in advance the approximate date of an observation so they can plan for coordinated observations and data analysis. Scheduling is complicated due to ongoing changes in the HST operational parameters and because the precise ephemeris for HST is not known in advance. Given these constraints, it is not possible to create a single static schedule of observations. Instead scheduling should be considered an ongoing process which creates and refines schedules as required. Unlike other applications of replanning, the HST problem places a premium on ensuring that a replan minimally disturbs the existing plan. A process and architecture is presented which achieves these goals by dividing scheduling into long term and short term components. The long term scheduler, the main focus of this paper, provides approximate 4-8 week plan windows for observations. A plan window is a subset of an observation's constraint windows, and represents a best effort commitment to schedule in the window. The long range planner ensures plan stability, balances resources, and provides the short term scheduler with the proper mixture of visits to create week long schedules. The short term scheduler builds efficient week long observation schedules by selecting observations who have plan windows open within the week.

The long term scheduler as implemented within the Spike software system provides support for achieving stable observations schedules. Spike models the planning process as a function which takes as input a previous plan, a set of proposals, and some search criteria and produces as output a new plan. Stability is ensured by using the input plan to guide the creation of a new plan. Through this mechanism Spike can handle instabilities such as changed observation specifications, out of date observation products, and errors in loading observation specifications. Special routines are provided for planning and ensuring stability for observations linked by timing requirements (e.g. Observation 2 after observation 1 by 6-8 days). Spike provides a combination heuristic and stochastic search engine with user defined weights for finding near optimal plans.

G. Hunt (NRAO)

The National Radio Astronomy Observatory (NRAO) has facilities at 17 different locations scattered throughout the USA. These vary in size from the major laboratories occupied by research and support staff to the ten individual antennas of the Very Long Baseline Array. As is typical in astronomy, many sites are in remote locations, which are not well served with modern communication capabilities. Until 1996, the NRAO's internal network was achieved via the Internet; most sites simply had a local port to the Internet and the traffic was routed tortuously to the other locations. The burgeoning demand for Internet bandwidth was (and still is) growing faster than the services could be enhanced, and this led to intolerably slow response times and unacceptably low achieved data rates. To solve this problem, the NRAO acquired a frame relay intranet to connect ten of its locations. The service is provided under the federal FTS2000 contract by AT&T. The operating cost is approximately the same as the multiple Internet connections, but with vastly improved throughput and reliability.

The past decade has witnessed an explosion of astronomical software development. Many talented individuals have made great efforts to develop libraries, programs, and analysis systems that serve the needs of their projects and the community at large. As a result, computer-aided astronomical research is vastly more sophisticated than it was even a few years ago.

One of the most striking features of this software explosion, considered as a whole, is the tremendous overlap in its functionality and its target audience. Why do we continually re-invent the astronomical software wheel? Why is it so difficult to use "other people's software"?

An approach to these questions can be made by contemplating the implications of the statement that "many talented individuals have made great efforts" to develop astronomical software. It is not enough simply to talk about cooperation in a theoretical way, and it is not possible to force cooperation. Rather, we need to investigate practically how individuals (and software) can begin to act in concert without sacrificing their independence or compromising the needs of their projects. This paper will examine these issues through specific examples and will offer a practical starting point for software cooperation, centered on the concept of "minimal software buy-in".

The HEASARC on the Web

The High Energy Astrophysics Science Archive Research Center is the premier archive for NASA's high-energy astronomy data. This demonstration will show a few of the capabilities that are provided to astronomers and the public at the HEASARC. These include:

- A complete, portable environment for analyzing high- energy data using FTOOLS and XANADU.
- Astronomical information from more than a dozen missions on the web using W3Browse.
- Immediate and easy searching of many HEASARC and remote Web sites for astronomical objects using the Astrobrowse system discussed at this meeting.
- The multi-wavelength virtual telescope: SkyView.
- Sophisticated educational resources for children and adults of all ages.

Description of the demo:

We intend to access the resources of the HEASARC over the Web and show a few programs running locally (or at least displaying windows locally). The demonstration will require a computer with graphical capabilities and Netscape V3.0 or higher or Internet Explorer V3.0 and higher. It would be substantially preferable to have a Unix system rather than a PC or a Mac. Some tools we would like to demonstrate require X-windows capability.

N.P.F. McKay, D.J. McKay (NRAL, Jodrell Bank)

This paper discusses the ramifications of the relatively new Java computing environment on the field of astronomy. It indicates the advantages and disadvantages of the language, concentrating on the specific needs of various aspects of astronomical computing. To illustrate some of the concepts, the authors present the Virtual Radio Interferometer (VRI), which allows the demonstration of aperture synthesis by simulating the Australia Telescope Compact Array and other observatories in software. This Java applet may be used as an educational tool for teaching interferometry as well as a utility for observers.

A. Micol (ST-ECF), P.D. Bristow (Bristol), B. Pirenne (ST-ECF)

The implementation of On-The-Fly Re-Calibration at the ST-ECF and CADC goes some way towards alleviating the problem of obtaining good and timely calibration of HST exposures. However, the data access paradigm is still to consider each exposure individually, re- calibrate them and offer the results to users, who subsequently process the data further.

We describe here techniques to automatically group together HST WFPC2, STIS and NICMOS exposures for cosmic ray removal, co-addition and combination into "super high resolution'" images. We show that the execution of these tasks has been made essentially automatic.

The ST-ECF archive now offers the possibility to select "associations'" of datasets and the automatically combined final products. A further spin off of this project is that more reliable pointing information for all exposures is provided.

Early Universe Simulation

Michael L. Norman (Laboratory for Computational Astrophysics Department of Astronomy and National Center for Supercomputing Applications University of Illinois at Urbana-Champaign)

The New User Interface for the OVRO Millimeter Array

S. Scott, R. Finch (Caltech/OVRO)

A new user interface for the OVRO Millimeter Array is in the early phase of implementation. The basic requirements are to provide monitoring and control of the array with a web based interface from anywhere on the Internet. Low bandwidth connections that are typically attained with analog modems must provide a satisfying interface.

Web browser based clients have been developed to display monitoring information from the array that is updated in realtime. These monitor clients are written in Java and are tailored to present different sets of information about the array. The data are usually rendered as numerical text values in data cells, with the color of the cells representing the state of the component. Many of the data cells are arranged in tabular form to provide a dense display and to emphasize the relationship of the data. The data cells in the table also function as the selection menu to initiate live realtime plots. This flexible plotting is a key feature of this new interface. Data caching and compression are two techniques used to enhance the utility of the monitor clients.

The monitoring clients are fed data over TCP/IP circuits from Unix server programs. These C++ server programs get their data from a large shared memory. The shared memory is updated twice a second by demon programs that receive datagrams from microprocessors embedded in the array hardware.

The control aspect of the interface is in the design stages as the Java security model evolves to provide the flexibility needed for remote access to control functions.

The ISO Spectral Analysis Package ISAP

We briefly describe the ISO Spectral Analysis Package ISAP. This package has been and is being developed to process and analyse the data from the two spectrometers on board ISO, the Infrared Space Observatory of the European Space Agency (ESA). ISAP is written in pure IDL. Its command line mode as well as the widget based graphical user interface (GUI) are designed to provide ISO observers with a convenient and powerful tool to cope with data of a very complex character and structure. ISAP is available via anonymous ftp and is already in use by a world wide community.

D. Tody and the IRAF Group (NOAO/IRAF)

The Image Reduction and Analysis Facility (IRAF) is an image processing and astronomical data analysis system developed by the IRAF group at the National Optical Astronomy Observatories (USA). The ADASS IRAF demo will feature the newly released IRAF Version 2.11, the latest X11IRAF visualization tools, portions of the Mosaic Data Handling System used for CCD data acquisition, and the distributed object and message bus data system framework being developed by NOAO. The IRAF group will be available to answer questions about the various aspects of the IRAF installations, reductions and programming tools.

Specific description of the demo:

We plan to demo the IRAF system. We will need a workstation or the equivalent: 17-20" color monitor, 600Mb of diskspace, a minimun of 32Mb of memory, SunOS or Solaris operating system running X Windows, DAT, Exabyte, or CD drive for downloading the software initially. We prefer a Sun workstation if at all possible.

Open IRAF Message Bus and Distributed Object Technology

D. Tody(NOAO/IRAF)

In this decade we have seen software become increasingly large and complex. Although programs may be well structured internally, using hierarchically structured class libraries to modularize the code, our programs have grown so large that they are monolithic and inflexible with a high degree of interdependence of the internal modules. The technology needed to address this problem, being developed now by academia and commercial consortiums, is known as distributed objects. Distributed objects allow major software modules to be encapsulated as objects and instantiated as separate processes, threads, or classes (procedures). Tying it all together is the message bus, which provides flexible services and methods for distributed objects to] communicate with one another. Applications are built by linking precompiled components and services together at runtime on the message bus. This paper presents the message bus and distributed object framework being developed by NOAO and outside collaborators as part of the Open IRAF initiative. This project is funded in part by the NASA ADP and AISR programs.

The design of a data reduction system for the NOAO Mosaic Camera was presented at the ADASS VI conference. This paper reports on the first implementation of this system as an IRAF package. Details and examples of the tools are given. Particular attention is given to the central role played by the coordinate system in producing high quality final images from a mosaic of CCDs.

We describe a new library (AST) which provides a flexible high-level programming interface for handling World Coordinate Systems (WCS) in astronomy. It includes, but is not limited to, a wide range of celestial coordinate systems and supports the Digital Sky Survey plate solutions and the draft FITS WCS proposals amongst other possibilities.

AST is a general tool for describing coordinate systems and the relationships which exist between them, and for storing this information in astronomical datasets. It also supports the retrieval, exploration and manipulation of WCS information, such as searching for coordinate systems, transforming coordinate values and aligning data arrays. A comprehensive range of graphics facilities is provided, including the plotting of annotated grids and axes.

Using AST, programmers may define their own new coordinate systems based on the built-in facilities. In future we plan to extend these facilities to include time, wavelength, and other coordinate domains.

Internally, AST makes extensive use of object-oriented techniques, but is written in ANSI C for portability and presents a conventional interface to FORTRAN and C programmers. Dependence on other software has been minimised and AST operates independently of any data system or environment, although it is easily interfaced to such systems when required. This, together with its flexibility, makes AST suitable for a wide range of projects.