Although the idea goes back to Ptolemy, the first true example of this class of objects wasn't observed until 1650, when Giam
Although the idea goes back to Ptolemy, the first true example of this class of objects wasn't observed until 1650, when Giambattista Riccioli focused his telescope on Mizar in the handle of the Big Dipper. More and more were discovered, including Virgins, Cygni and Castor, eventually leading Herschel to set down a strict definition and to name them in his 1802 paper, "On the Construction of the Universe". FTP, name these astronomical objects, now separated into visual, spectroscopic, and eclipsing types.
Although the idea goes back to Ptolemy, the first true example of this class of objects wasn't observed until 1650, when Giambattista Riccioli focused his telescope on Mizar in the handle of the Big Dipper.
binary stars