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THE IMCCE VIRTUAL OBSERVATORY
SOLAR SYSTEM PORTAL
Observatoire de Paris / CNRS

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- SsODNet -
The Virtual Observatory
Solar system Open Database Network

Current version: SsODNet2/Quaero - 2017-02-22

> Presentation

The SsODNet project aims to build the core of a VO-compliant information system dedicated to the solar and extrasolar system objects, to enable astronomers to explore and to retrieve various parameters, directly from their desktop or preferred VO softwares.

SsODNet is developped by the VO-IMCCE team, in the frameworks of the International Virtual Observatory Alliance. It was thought to meet the requirements of the planetary scientist community, in particular to provide an easy access to data which are used daily. The core of SsODNet is a name resolver, which provides basic information for all solar system and extrasolar bodies: planets, satellites, asteroids, comets, spacecrafts and spacejunk orbiting the Earth, and exoplanets. SsODNet is also a data aggregator, thought to allow planetary scientists to share with each other their planetary data collections and services.

> Scientific issues

Faced with the huge amount of planetary data, astronomers have to dig many sources of databases to collect information on the solar system objects. SsODNet aims to answer this, by proposing an information system which provides an easy access to planetary data. For that, SsODNet relies on two corner stones:
Quaero, a name resolver
to seek for and identify (extra)solar system object names, and resolve them into celestial coordinates
a data aggregation engine (in development)
to seek for all the resources referring to the requested target(s) within the shared databases

The resources which are available through SsODNet are composed of heterogeneous dataset of astronomical products shared by planetary scientists. SsODNet just acts as a hub which ensure the connection and the interoperability of the data (i.e. no transformation or conversion process).

> Technical issues

SsODNet Architecture

The figure herein enlightens the global architecture of SsODNet, which is composed of three layers: a user interface, a data access layer, and a cloud of data.

The user interface acts as a client of the service. It gathers the parameters, composes the user's request, and posts the request to the end points of SsODNet. A simple manner to do this is to use a data transfert program, such as curl or wget, and to send HTTP requests to the Web API (recommended to normal users), or directly to the Web service or the REST APIs (recommended to developers). A personal Web interface can easily be developed to manage the requests and display the results. Feel free to make your own! or just use our Web form.

The data are accessed through two APIs:

  • - a high level Web service, built uppon a XML+SOAP technology (public interface (WSDL), SsODNet server), which allows to resolve a name, or to get data (TBD)
  • - a low level REST API, named Quaero, written in Python, which is the name resolver itself. Its public interface provides an easy and fast method to resolve or to discover (extra)solar system objects.

The data cloud refers to all the data which are collected and, for some of them, stored into the SsODNet databases, powered by Elasticsearch and MariaDB database engines. The main sources of data exploited by SsODNet are the following:

The celestial coordinates of all solar system objets are computed by the Miriade Web service. The coordinates of the extrasolar planets are obtained through the PADC TAP service of the Extrasolar Planets Encyclopaedia. Their ephemerides are computed by Miriade, and are based on the celestial coordinates (proper motion, parallaxe, ...) of the parent stars collected via the script API of the SIMBAD astronomical database.

.: User support

Each response sent by the SsODNet Web service contains a ticket number. This 13 digits number (e.g. 1483486493734) identifies each request and may be used to retrieve information on its processing. If you face with errors by using the SsODNet service (it could occur that no relevant error message is returned), please report us the ticket number corresponding to the problem. It will help us to anderstand and solve it, and you will help us to improve the services.

The information regarding requests sent to SsODNet is stored in a dedicated database. No personal information is stored, except the IP address of the client, which is employed to make statistics on the geographical localization of the SsODNet users. The SsODNet logs are never disseminated nor sent on request. You can access to the public logs by using the following URL:

http://vo.imcce.fr/webservices/ssodnet/showLog.php?ticket=[#ticket]&method=[method]
where:
#ticket
Ticket number of the request
method
Keyword defining the service: SsODNet(resolver), SsODNet(getAvailability)

If you are confronted with a bug, or if you would like to request improvements or special needs, please use the IMCCE Mantis Bug Tracker (quick access: use the Report issue menu in the portal menubar).

.: How to cite SsODNet

If SsODNet was helpful for your research work, the following acknowledgment would be appreciated: "This research has made use of IMCCE's SsODNet/Quaero VO tool (http://vo.imcce.fr/webservices/ssodnet/)".