Understanding ... SIDONIe

¤ ¤ Presentation

¤ ¤ Precisions on the data

¤ ¤ Some definitions

¤ ¤ Technical characteristics of this base

¤ ¤ Interrogation - parameter formats

The measurement of double stars is of primary importance for the determination of stellar masses, a fundamental parameter in astrophysics, in general.

SIDONIe (Site Informatique des étoiles Doubles de Nice) recovers all the measurements of a handwritten file, compiled principally by Mr. Paul Couteau, an astronomer at the Côte d'Azur Observatory, a file which the Fresnel Department at the Côte d'Azur Observatory has decided to save.

The measurements have mainly been acquired by a visual technique (mostly with a filar micrometer and, infrequently, a double image micrometer) but there are also photographic measurements (the most widely spaced couples), interferometric measurements (mostly speckle interferometry for the couples closest together) as well as CCD measurements, particularly on the 74cm and 50cm telescopes of the Côte d'Azur Observatory.

This database was not conceived to provide exhaustive information on the various identifications of the objects cited here ; for that reference can be made to the many other existing catalogs (see CDS).

Part of what is found in SIDONIe are double stars discovered by Paul Couteau using the classic method of filar micrometer (around 2,700 couples). Measurements made on visual couples with a separation inferior to 1 arcsecond or possessing an obvious orbital movement north of a - (minus) 10° declination.
The rest of SIDONIe also contains a large number of measurements recorded since 1773. The file contains more than 12,700 couples in which the separation is inferior to 2 arcminutes

This database is updated by the contribution of new data coming from published observations and new observations made at the  Côte d'Azur Observatory by amateur observers.

Description of given data :

Identification of an object
Alpha and Delta : coordinates for equinox 2000
Name : corresponds to the star observed. Most often it is composed of three letters designating the discoverer followed by a number, if the number is negative it means that there is no more information than the letters
ADS # : Number in the Aitken Double Star catalog
BD # : Number in the Bonner Durchmusterung catalog
HIP # : = HIC, number figuring in the "Hipparcos Input Catalogue"
mag1 and mag2 : magnitudes of both components, given by the discoverer
Spectral type : given by the discoverer. The particular types and class, when they appear on the original manuscript file, have been reported in the notes
Orbit ? : Parameters for calculated orbits can be found in the annex. 854 objects are noted, the first period having been indicated by Doberek in 1877

Date : precise date of observation, year and fraction of the year
Angle : in degres and fractions of degrees
Separation : in arc seconds and fractions. When there is no measurement : value = 0. When measurements are approximate, uncertain, etc. that indication is reported in the notes.
Number of nights of observation : If there were several observers on the same date, the total of nights is indicated, details of observers' codes appear in the notes.
Observer code : The codes used here are the same as the CDS, "Centre de Données Stellaires" (Stellar Database Center) in Strasbourg and the Washington catalog.
Instrument - Dimension : reflector or refractor telescopes, dimensions are given in centimeters or inches ("). When the method is specified, it is mentioned in the notes.
References : These are references to publications of measurements.

Definitions :

* Double Star : A system of two stars, physically connected according to their mass ratio
* Filar micrometer : an optic instrument, situated at the level of the eyepiece, which allows one to measure, by eye, the separation of two objects. It consists of crosshairs to target the object and a scale (in microns) to give the value of the measurement.
* CCD : A detector allowing a rapid reading of information thanks to electronic transfer, which, in turn, allows to increase the precision of measurements to + or - 0.005" of separation angle and = or - 0.5° of position angle.
* (Apparent) Magnitude : Units of measurement (logarithmic) of the starburst (m1 - m2 = -2.512 log E2/E1)

Technical characteristics :

This database was created using MariaDB (MySQL) software running on a Linux server.
(Previous versions: This database was created using a Microsoft ACCESS program with a PC type computer.)
This database was financed by the CNRS-INSU and the Nice-Côte d'Azur Observatory.
The conception, set-up, research and verification, necessary to the creation of this database, was provided by permanent staff at the CNRS, Enseignement Superieur, also by temporary personnel and volunteer amateur astronomers.

Using this database ; interrogations & formats :

There are two ways to use this database :
- Research on a specific object
- Statistical research
For the latter, several parameters may be chosen at the same time. The guidelines are specified on the form.

Every publication using this database content should mention it !

Thanks for reporting any error(s)...