DOUBLE STAR ORGANIZATIONS 
(all links open in a new window-you will be returned to IADSO when you close the window out)

International Astronomical Union Commission 26
Double and Multiple Stars
http://www.iau.org/science/scientific_bodies/commissions/26/

Double star organizations listed on the IAU Commission 26 web site 

• The Journal of Double Star Observations
  a quarterly journal of amateur astronomy dedicated to the study of double and binary stars
• The Webb Deep-Sky Society (Double Star Section)
  an amateur/professional society specializing in double stars and 'deep sky' objects
  (There is also a direct link to the Webb Deep-Sky Society Circulars.)
• Astronomical Society of Southern Africa (Double Star Section)
  another fine society for amateur double star observers
• The "Spirit of 33"
  an international network of amateur double star observers, based in Spain
• The Double Star Section of LIADA",
  the Spanish American League of Astronomy
• The Double Star Club of the Astronomical League"
  an association of local amateur astronomical societies across the United States
• The Double Star Commission of the French Astronomical Society"
  an amateur/professional double star group whose members publish in the SAF journal Observations et Travaux
• Garraf Astronomical Observatory
  Located near Barcelona, Spain and headed by Tofol Tobal, this organization has published over 10,000 visual double star observations in its "OAG General Catalog"
• "El Observador de Estrellas Dobles"
  a Spanish language electronic double star journal begun in 2009
• "Il Bollettino delle Stelle Doppie"
  a new Italian language electronic double star journal begun in April 2012

LINKS
Double star links listed on the IAU Commission 26 web site:
(all links open in a new window-you will be returned to IADSO when you close the window out) 

• Washington Double Star Catalog (WDS)
  (Mason, Wycoff, & Hartkopf 2001; updated nightly)
  see also "Neglected Doubles" Observing Lists
• Fourth Catalog of Interferometric Measurements of Binary Stars
  (Hartkopf, Mason, & McAlister 2001; updated frequently)
• Sixth Catalog of Orbits of Visual Binary Stars
  (Hartkopf & Mason 2001; updated frequently)
  see also list of "Calibration Candidates"
• Catalogue of Orbits and Ephemerides of Visual Double Stars
  (Docobo, Ling, Prieto, Costa, Costado & Magdalena 2001)
  The catalog is also available in Galego and Castellano.
• Multiple Star Catalog
  (Tokovinin 1997; last update April 2010)
• USNO Third Photometric Magnitude Difference Catalog
  (Mason & Wycoff 2001; updated nightly)
• Catalog of Rectilinear Elements
  (Hartkopf & Mason 2011; updated occasionally)

• CDS: Centre de Donnees astronomiques de Strasbourg
• Hipparcos
• SIMBAD Astronomical Database
• SIDONIe: the double star website of Nice Observatory
• ADS: NASA's Astrophysical Data System bibliographic database
• CHARA: GSU's Center for High Angular Resolution Astronomy
• OLBIN: Optical Long Baseline Interferometry Newsletter
• NEXSci: NASA Exoplanet Science Institute (formerly Michelson Science Center),
  also talks from the 2009 Sagan/Michelson Fellows Symposium
• The General Catalogue of Photometric Data