The FITS archive
The HyperLeda FITS archive (HFA) has
been open in January 1999.
In June it contained about 35000 files.
The archived data are broad band images
(BBI) and long-slit spectra
(LSS) plus their associated template and calibration files.
The data in HFA can enter into the
HyperLeda processing pipeline
and the results can be freely downloaded.
The team involved in the project
- Philippe Prugniel (Observatoire de Lyon)
- Gregory Maubon (Observatoire de Lyon)
- Valeri Golev (University of Sofia)
- Francois Simien (Observatoire de Lyon)
- Roberto Rampazzo (Osservatorio di Brera, Milano)
...... The rest of this page is out of date .....
The pre-PhaseA study has been conducted by Ph. Prugniel and V. Golev
and resulted in the present document.
The idea is to initially restrict the
project to an archive of 2 dimensional spectra of galaxies:
The pre-PhaseA resulted in:
|Definition of the file system (structure of the archive)
|Preliminary definition of the FITS keywords
|Implementation of low-level routines for accessing the
|Implementation of the index of the HFA
The aim of Phase A was to design a
"pipe 0" efficient enough to convince
everybody that using this system of archive is not a waste of time.
Phase A was terminated on Dec. 22th 1998. It resulted in the archiving
of several dataset, including the "Library of Medium Resolution
This allowed to check and improve the consistency of the set of
At this stage, a preliminary definition and implementation of the
pipeline processing was achieved.
[The obtained with "Library of Medium Resolution Spectra" contains data
the CARELEC spectrograph over the period 1992-1998. They are described
in the series of papers by Simien and Prugniel (1997a,b,c 1998)
and by Golev et al. (1998).]
The HFA is presently stored in Lyon, but the architecture allows for a
segmentation on several file systems possibly located in different
(A segment of HFA will be soon located in Milano).
The HFA is mirrored on two HyperLeda mirrors (Lyon and Brera), the other
HyperLeda mirrors redirect the requests to Lyon.
Phase B will extend over the first semester of 1999.
We will work as soon as possible on a serious implementation of Pipe0,
We will add different processing procedures on the pipeline:
sky subtraction, cosmic removal, filtering...
We will implement analysis procedures on the pipeline, in particular
the line strength analysis and stellar kinematics standard procedures.
II. Data contained in the archive
The archive presently contains both
images and spectra.
The images are broad ban images in U B V R and I but does not
any complete sample. We will add further dataset in the future.
The spectra make a complete collection of the observations done with
CARELEC spectrograph (OHP) in the frame of the large programs
the fundamental plane of early-type galaxies and the scaling relations
of spirals (Prugniel, Simien and collaborators).
The Library of Medium Resolution Spectra
(ie. resolution = 1000 to 3000)
- Spectra of the galaxies
- Spectra of the template stars
- Arc-lamp spectra
- Tungsten-lam spectra
is the software used for the support of this archive.
- The interface with FITS data is based on the
Issues to address
Classification of the keywords
|Keywords independent of the processing
Unaffected by "linear" processing, like flat-fielding, w-calibration,
cosmetic processing, analysis... But possibly affected by "non-linear"
processing like combining frames (average flat-field), compositing
frames (eg. to remove the cosmics)...
Telescope, Instrumental frozen setup, Detector
Characteristics of the actual observation
| H_DTSET dataset identifier
H_CONTXT context: LSS, BBI, ...
H_DRON Detector Read out noise, in electrons
H_DPIX Detector Pixel size (in microns)
Slit width (arcsec)
| DATE-OBS Date of observation
MJD-OBS Date of observation
EXPTIME Exposure time
OBJECT Object identifier
H_TYPE Type of exposure
PA of the slit
|Keywords affected by the processing
| Gain [e/ADU]
Saturation level [ADU]
| Image size
Sky value [ADU]
Magnitude calibration constant (mag/arcsec2)
|Keywords affected by the processing