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Dolensky, M., Pirenne, B., Binegar, S., Brandt, B., Gaffney, N., Arviset, C., & Hernandez, J. 2001, in ASP Conf. Ser., Vol. 238, Astronomical Data Analysis Software and Systems X, eds. F. R. Harnden, Jr., F. A. Primini, & H. E. Payne (San Francisco: ASP), 90
Quick-look Applet Spectrum 2
Markus Dolensky1, Benoît Pirenne
Space Telescope - European Coordinating Facility, Karl-Schwarzschild-Straße 2, D-85748 Garching, Germany
Scott Binegar, Molly Brandt, Nial Gaffney
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218
Christophe Arviset, Jose Hernandez
ISO Data Centre, European Space Agency, Space Science Department,
Astrophysics Division, Villafranca del Castillo, PO Box 50727, 28080
Madrid, Spain
Abstract:
Spectrum 2 is a new quick-look applet for spectra. It serves
as part of the ST-ECF HST archive web interface. Prior to display the ESO
Fits
Translation Utility
(FTU) is used to
homogenize plots of data from HST instruments STIS, FOS and GHRS.
Spectrum 2 supports manipulations of multiple spectra. It will
also be integrated within STScI's new archive browser StarView 6.
A stand-alone version of
Spectrum 2 is available for
download.
This article concentrates on the software architecture and interfaces
of this java utility since it is composed of various components mainly
developed by ESA-IDC and ST-ECF.
Figure 1 shows Spectrum 2 in context of the ST-ECF
HST archive web interface (http://archive.eso.org). On user request preview
spectra are retrieved from the archive DB. The ESO Fits Translation
Utility (FTU) adds special purpose FITS keywords in order to homogenize
plots of spectra from HST instruments STIS, FOS, and GHRS. The resulting
FITS stream is transmitted to the web client. The web browser hosts
the java applet Spectrum 2. The applet reads the data stream
using a FITS I/O package developed by McGlynn/USRA and then parses
certain keywords in order to define a plot (Figure 3).
Currently there exists a parser for ISO data and one for HST spectra.
The ISO parsing capability has been implemented first. This happened in
cooperation with the ISO Data Centre.
For the sake of browser support the GUI is based on the Abstract Windowing
Toolkit (AWT) rather than on the more powerful Swing libraries. AWT is
part of the Java Virtual Machine that executes Spectrum 2 and
therefore does not require any installation on the client side. The actual
plot is rendered with Brookshaw's Graph Class Library. A user does not
need any knowledge about the internal data structure of HST observations
to perform a quick on-line evaluation of individual or associated spectra.
Figure 1:
Software components involved in the client/server environment of Spectrum 2.
|
Spectrum 2 provides various machine interfaces
(Figure 2). It accepts parameters from the command line in
application context and from the HTML APPLET tag in applet context.
It is capable of parsing FITS headers in order to extract plot attributes
and finally it can communicate with other Java components via shared
objects by which means it can be hooked up to StarView 6 from STScI.
Figure 2:
The various machine interfaces of Spectrum 2.
|
Figure 3:
Spectrum 2 displaying 16 associated FOS spectra of Eta Carinae (PI Davidson).
|
- The first release will be further tailored to support the visualization and on-line analysis of associations of spectra: Binning and features for the manipulation of individual spectra within an association of spectra are desirable.
- Spectrum 2 software releases will be made available for
download.
- Integration within archive browser StarView 6: There will be a static interface comparable to the interface with image viewer JIPA (Dolensky, Mayhew, & Kennedy 1998), but it may be turned into a dynamic Bean component at a later stage.
References
Dolensky, M., Mayhew, B., & Kennedy, B. 1998, in ASP Conf. Ser., Vol. 172, Astronomical Data Analysis
Software and Systems VIII, ed. David M. Mehringer, Raymond L. Plante, &
Douglas A. Roberts (San Francisco: ASP), 454
Footnotes
- ... Dolensky1
- Affiliated to the Astrophysics Division, Space Science Department, European Space Agency
© Copyright 2001 Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, California 94112, USA
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