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.