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Boch, T., Fernique, P., & Bonnarel, F. 2003, in ASP Conf. Ser., Vol. 314 Astronomical Data
Analysis Software and Systems XIII, eds. F. Ochsenbein, M. Allen, & D. Egret (San Francisco: ASP), 221
New features for Aladin 2.0
T. Boch, P. Fernique and F. Bonnarel
Centre de Données astronomiques de Strasbourg, Observatoire de Strasbourg, UMR 7550, 11 rue de l'Université, 67000 Strasbourg, France
Abstract:
We present the main new features of the Aladin interactive sky atlas (version
2.0, November 2003). The Aladin tool is able to query a remote server
providing new VO DAL
1 outputs and to
interpret the result. Aladin is able to build a metadata tree from the
description of a dataset, in order to easily browse through all data available
in a sky region on a server or in a local folder. It is now possible to interface Aladin to other Java applets in a standard way, and
this has been applied to VOPlot. In addition, Aladin can now parse VOTables from various origins.
It is also possible to recalibrate the astrometry of images,
using different astrometric reduction methods, or to create manually a new
calibration using a reference catalogue. Other miscellaneous changes have
been implemented.
The AladinJava tool was first released in 1999 long before the VO efforts
started. Version 2, released just after ADASS 2003 meeting is a major new
release implementing several new features and enhancing the role of Aladin
as a VO portal (Figure 1). Several new developments described here have
been initiated for the AVO prototype.
Figure 1:
RGB image built from 3 plates (ESO/R, SERC/SR, and SERC/I) with Tycho2
catalog overlay and a filter displaying the proper motions for the faint stars
in the Trifid nebula field.
![\begin{figure}
\epsscale{.60}
\plotone{P2-32_1.eps}
\end{figure}](img1.gif) |
The emerging VO standards are already implemented in Aladin, allowing users
to access VO image and data servers, immediatly available in Aladin by
describing these servers in the GLU registry.
VOTable has been the first IVOA standard. Defined as an XML DTD,
VOTable is intended to provide a common standard for astronomical tables, or
Іtable sets. A light VOTable parser, SAVOT, has been implemented in Java
and integrated to Aladin. It allows to access various servers of
astronomical
catalogues, as well as metadata descriptions such as SIA and IDHA servers
(see below)
This Java interface between two collaborative applications describing how to transmit data, how to select astronomical objects allows one to integrate external tools into Aladin, as long as they are able to cope with VOTable, e.g. VOPlot (Figure 2) - VOPlot is a VO-India/CDS collaboration (S.Kale et al, 2004) -
Figure 2:
VOPlot drawing (proper motion compared to BT-VT) for Tycho2 objects displayed in Figure 1
![\begin{figure}
\epsscale{.60}
\plotone{P2-32_2.eps}
\end{figure}](img2.gif) |
ExtApp makes easier collaboration with other projects. Miscellaneous applications
have been tested, but not yet retained in the public interface.
Strong effort has been made in the IVOA to provide standardized access to
images available on the WEB. SIA protocol
standardizes the image request
and image retrieval methods. SIA compliant servers provide metadata for the
images in VOTable format. Developped in parallel to SIA, and based on the
IDHA data model, IDHA VOTable used in the
AVO scientific demonstrations provides more structured metadata.
Aladin is now able to request both DAL compliant servers and to interpret
the outputs (see next section).
This feature organizes image metadata in a uniform way ,
allowing to browse huge datasets and select data within them.
Currently the only condition is that MetaData are provided in IDHA VOTable or SIA protocol format. Data in local directories will appear in the same
coherent structure. The metadata tree feature makes Aladin a strong
data integrator (Figure 3).
In addition to this user directory ``autoscan", it is also possible to read
``hand made" local metadata documents (SIA or IDHA compliant) and to
describe in the GLU dictionnary any server returning either VOTable or
SIA/IDHA VOTable. Using these descriptions, the Aladin software generates
dedicated dialog boxes for each server.
- Online reduction
This dynamical computing feature allows to fix wrong astrometric
solutions, to achieve compliance between astrometric solutions of a set
of images, to compute solutions for uncalibrated images and convert XY
positions catalogues to World coordinates.
- Value scaling facility
In previous versions of Aladin the ``autocut" facility provided appropriate
value scaling for most of the images. In this version we added to this ``autocut"
the possibility of choosing the extrema of the scaling interval.
- Help menu to write filters
The filter facility implemented in the previous main release was lacking
a user-friendly way of writing new filters. A popup menu provides now assistance to the user in this task.
- New script commands to manipulate stack folders
The script facility allows automatic command executions. It is useful
for large data sets processing. This scripting facility has been extended
to allow stack folder manipulation.
All the developments described in this paper are fully available in both
the applet and standalone versions. They are compatible with Java Virtual
Machines version 1.1, the proportion of which among installed browsers
begin
still 60%.
Acknowledgments
The authors acknowledge support by French Research Ministery ACI Grid
for IDHA and by EC founded AVO for DAL and metadata tree implementation.
They thank Mark Allen, Mireille Louys and André Schaaff for various
collaborations
Figure 3:
Metadata tree provided by Aladin server in the Trifid nebula field displayed in Figure 1
![\begin{figure}
\epsscale{.60}
\plotone{P2-32_3.eps}
\end{figure}](img3.gif) |
References
Kale, S. Vijayaraman, T.M. Kembhavi, A. Krishman, P.R. Navelkar, A.
Hegde, H. Kulkarni, P. Balaji, K.D. 2004, this volume, 350
Footnotes
- ... DAL1
- Data Access Layer
© Copyright 2004 Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, California 94112, USA
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