Start here - primer to using the OSA
Login info - Regsitered users should first login as
some of the information and forms are tailored to a specific type of user. If you do not
login your queries
will be directed to any world accessible VST survey data.
Categories of user access:
- registered VST survey user - Public Survey team members from ESO countries(eg the ATLAS
- un-registered user - can access VST survey data once the respective proprietary periods have
passed (see data policy).
Archive contents The OmegaCam Science Archive contains
static released databases of survey data. Image metadata
and source catalogue data are held in the databases, with links to flat
FITS files produced by pipeline processing. Once released, survey databases
will not change.
In addition to the static databases, access to a continually updating
database (known as "OSA") is also allowed for registered users to get
to pipeline-processed flat FITS files in order to facilitate casual browsing
of survey data. Note however that this
OSA ingest database is subject to data modification (ingest, rollback, quality control)
without warning. After an
appropriate proprietary period has expired, data and/or databases will
become open-access for unregistered access by anyone. A more
detailed description of the data and how it is held in the archive is given in the
data overview. The contents of the various releases of the VST surveys are shown on the surveys page.
More detailed coverage plots are available in the form of Multi-Order Coverage (MOC) maps.
Particular attention should be given to notes detailing limitations and known issues, see overview
and release history.
The database schema and contents can be explored using the
Accessing data - the various ways of accessing and querying the archive are also
listed on the data access page. First-time users should consult this page
in addition to reading the summary below.
- Image data - VST images (referred to as multiframes) are held in the archive
as multi-extension FITS files.
- Image List - list and retrieve the full FITS files of multiframes (also returns links to any associated catalogue FITS files)
- GetImage - extract image cut-outs
from multiframes around a given position.
- MultiGetImage - upload a
list of coordinates and extract matching image cut-outs.
- Catalogue data - source extraction code run on science multiframe images
produces catalogue FITS files. The objects in these files are ingested into the relevant
survey/programme detection table (e.g. atlasDetection). VST surveys also have a source table
(e.g. atlasSource) which is
populated by merging common objects (based on
position) across the various wavebands.
- Region search - search
the catalogue data (detection or source tables) around a given position.
- Freeform SQL - submit an SQL query directly.
Allows the more experienced user to perform powerful SQL searches of the archive (see the
SQL cookbook for examples).
- CrossID -
upload a list of coordinates and extract matching objects from the
detection or source tables.
- Meta-data - header information and other meta-data from the archived FITS
files are also stored in tables in the archive. The ones that are most likely to be used are
multiframeDetector and currentAstrometry. These can be queried using
- Help - please consult the following documentation
before contacting us for help.
If you still cannot find the answer to your problem in the above documentation, then email us (email
address is given right at the bottom of this page).
WFAU, Institute for Astronomy,
Royal Observatory, Blackford Hill
Edinburgh, EH9 3HJ, UK