The links to WEBDA tools and facilities are grouped in the navigation panel which is the heart of the site.
In each channel, four levels have been distinguished:
Both methods finally present lists of open clusters and provide links to
each cluster page, which is the starting point for further queries. The
clusters are ordered by alphabetical order.
The query of stellar data
The page built dynamically for each cluster, like that for
NGC 4755, is the starting
point to query the database in more depth and access the stellar data,
display images and make data plots.
The cluster page is the place collecting most available knowledge on the clusters, starting with the usual cluster parameters (coordinates, distance, age) and a photography, when one is available. The data retrieval is conceived as
If a chart has been scanned and is displayed on the screen, it is tempting to click on a star numbered on the chart to know what it is. This facility has been developed for 200 clusters for which have an convenient chart has been published. A click on any numbered star will display the basic data, like the coordinates, the BS, HD or DM numbers, the UBV magnitudes and colours and spectral type.
The colour-magnitude diagram is the most meaningful summary of the cluster
properties and one is proposed for many clusters based on the UBV
photometric data. Other planes are of course interesting and these can
be plotted on-line on the user demand. If more specfic work is required, it
is always possible to copy data from the database to the user's computer and
plot any diagram with the favourite graphic package. This is why links areprovided to the existing archive data files, if any.
The retrieval of archive data
Because a long use of the database over the Net may be tedious,
the possibility is also offered to download selected, or all, data files
for a cluster and copy archive data files. The links to ftp archive data
are located at the bottom of the cluster pages.
All the information on the archive data file has been gathered in the
list of archive files in the
information channel. Each item presents the cluster name, the kind of
data each file contains and the reference to the published paper.
The access to the literature
This site offers another possibility to access the astronomical literature
on open clusters. This may be useful in the sense that there are no prior
selections on journals or books. In addition keywords have been attributed
to permit the required versatility in bibliography query.
The bibliography on open clusters covering the period from 1969 to present days can be accessed:
The "SIMBAD / NED" bibcodes have been added to the bibliographic files to provide a link to ADS Abstract Service and get the article abstracts.