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I N S T R U C T I O N S F O R
U S E
Access to the database of observations.
In order to enter the database of
the observations of the natural planetary satellites, please select the
topic "observations" in the menu of the "NSDC" home page or in the top of each page.
Then, it is possible to choose either the database of raw published data "NSDF" or
the standard dtat "NSDB".
In the first case, you will have to select the group of satellites
and the nature of the observations: "astrometric positions" or "phenomena".
These observations have their characteristics described in a guide.
In the second case,
if you wish to get data under a standard form gathering all data, click
on the column at right. At the present time, only a few observations
are included as standard dtat, mainly the for the galilean satellites.
The link to "Parameters"
put at the top of all pages provides many useful data as:
- the list of the satellites with orbital and physical parameters
- the masses of the satellites according to several sources
- the parameters of the rotation and of the coordinates of the poles.
Before selecting the group of satellites, it is possible to have a look to the
list of all satellites in the link "Nomenclature".
After the choice of the group of satellites, you will get the list of all the "entries" of observations.
Then it is possible to choose selected observations.
This page is made of three frames (the header, the list of the entries
and the bottom. The scrolling is made independently for the three frames. Each line
of the list corresponds to an "entry" and to two files the names of which having a specific meaning as follows:
- The first character is the first letter in the name of the planet (m,
j, s, u, n).
- The second character denotes the satellite group: m -
major satellites, g - Galilean satellites, i - inner satellites, o -
outer satellites.
Then, in the identifier, follows the ordinal number of the
set (four characters). The ordinal numbers may be limited within certain ranges
for some satellite subgroups. Each set in the database is provided with two files:
file of explanations (Content) and file of data (Data).
The identifier of
set appears in the identifiers of file of data and file of explanations for this
set as a name of file.
File of explications (Content) *.html. This is a text file accessible for
reading and copying by user. It has HTML extension. Explanations include different
information which is common for all sets of data. The format of file of data is
described here too. File of explanations is composed according to the specific rules
mentioned above. In the file of explanations, source of data or bibliographic
reference is indicated. The reference has a hyperlink which may be used to call the
corresponding reference from the bibliographic database. From there, in its turn, it
is possible to go to the corresponding reference at the ADS Abstract Service where
the electronic version of the publication is accessible.
File of data (Data) *.txt. It is also a text file containing the results of
the observations in the format described in the file of explanations. According to
the principle adopted in our database, all observational data are entered into the
database in that content and form in which they were received or published. No
reductions or transformations are made. Only the order in which data follow may be
changed. Usually one single line of file corresponds to one observation made in
the given date. All numerical values in the line are separated by one or more
spacings. As a rule, lines contain only numerical values. Character values given in
the data sources are replaced by numerical ones. In some cases, a special symbol or
a word may appear instead of numerical value, which is specified in the file of
explications.
The file of explications as well as the file of data may be copied by the
user using any Web browser (Netscape, Internet Explorer, etc.) or using tools
offered by OS Windows. These are the only data accessible to the user.
Pour certains types d'observations (par exemple les phénomènes mutuels)
on trouvera deux fichiers "Data", l'un correspondant à des données numériques
réduites et l'autre aux données photométriques brutes permettant à l'utilisateur de
refaire lui-même la réduction.
Les données standard de la
base NSDB (Standard Data)
Le but de cette partie de la base
de données est de fournir des données standard sur lesquelles un travail
d'homogénéisation a été effectué. Toutes les données correspondant ,à un
satellite ou à un groupe de satellites sont regroupées et directement
utilisables contrairement aux données brutes originales de la base NSDF qui
doivent être homogénéisées avant utilisation.
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