assigned not by Flamsteed himself but by the French astronomer J. J. Lalande in a French edition of Flamsteed's catalogue published in 1783. The Gould designation for stars visible from the southern hemisphere, introduced by Benjamin Gould (1879), also lists stars by constellation, numbered by increasing right ascension. Hevelius and Bode both numbered stars within constellations similarly. Their number systems have fallen out of use, but their designations even now are occasionally mistakenly treated as Flamsteed designations. 47 Tucanae, a number assigned by Bode, is a famous example. Full-sky catalogues Full-sky star catalogues detach the star designation from the star's constellation and aim at enumerating all stars with apparent magnitude greater than a given cut-off value. The Histoire céleste française (1801) enumerated 47,390 stars to magnitude 9. The Bonner Durchmusterung (1859) was the most complete star catalogue compiled without the aid of photography. It listed a total of 320,000 northern stars, expanded by the Cordoba Durchmusterung (1892) and the Cape Photographic Durchmusterung (1896). The Henry Draper Catalogue (1924) listed 225,300 stars to magnitude 10, extended to a total of 359,083 in 1949. The HD numbers remain in widespread use for stars that do not have a Flamsteed or Bayer designation. The Bright Star Catalogue of 1930 listed all stars brighter than magnitude 6. It was supplemented to include stars down to magnitude 7.1 in 1983. The Catalogue astrographique was compiled between 1891 and 1950 with the aim of listing all stars to magnitude 11, resulting in a list of 4.6 million stars. It is under continued development, now under custody of the U.S. Naval Observatory. The USNO-B1.0 catalogue contains over a billion objects, and is also under continued development at the U.S. Naval Observatory. The online Guide Star Catalog II (2008) contains 945 million stars to magnitude 21. Variable designations Variable stars that do not have Bayer designations are assigned designations in a variable star scheme that superficially extends the Bayer scheme with uppercase Latin letters followed by constellation names, starting with single letters R to Z, and proceeding to pairs of letters. Such designations mark them as variable stars. Examples include R Cygni, RR Lyrae, and GN Andromedae. (Many variable stars also have designations in other catalogues.) Exoplanet searches When a planet is detected around a star, the star is often given a name and number based on the name of the telescope or survey mission that discovered it