Observing and measuring visual double stars Double stars are the rule rather than the exception: our solar system having a single sun is in the minority. Orbiting satellites ground based observatories and interferometers have all helped discover many hundreds of new pairs but this has left enormous numbers of wide faint pairs under observed or not observed at all. This is where amateur astronomers can help. Bob Argyle a professional astronomer at Cambridge University shows where enthusiastic amateur observers can best direct their efforts. The book caters for the use of every level of equipment from simple commercial telescopes to micrometers and CCD cameras. Amateur astronomers who have gone beyond sight seeing” and want to make a genuine scientific contribution will find this a fascinating and rewarding field and this book provides all the background and practical information that’s needed. More Than One Sun Why Observe Double Stars The Observation of Binocular Double Stars The Scale of Binary Systems Multiple Stars and Planets Is the Sun a Double Star The Orbital Elements of a Visual Binary Star Orbit Computation Some Famous Double Stars The Resolution of a Telescope Reflecting Telescopes and Double Star Astronomy Simple Techniques of Measurement The Double Image Micrometer The Diffraction Grating Micrometer The Filar Micrometer The CCD Camera Speckle Interferometry for the Amateur Lunar Occultations What the Amateur can Contribute Some Active Amateur Double Star Observers An Observing Session Some Useful Formulae Star Atlases and Software Catalogues Publication of Results.