Bonner Durchmusterung (Southern Durchmusterung)

The Southern Durchmusterung (SD, Schoenfeld 1886, Becker 1949, Schmidt 1967) is a visual survey of stars in the declination zones -02 to -23 deg, completed as an extension to Argelander's (1859-62) monumental Bonner Durchmusterung (BD). Schoenfeld's survey was carried out using the same methods as had been used for the BD. The procedure consisted of allowing the telescope to drift along the mean declination of each zone and recording the positions and magnitudes of stars crossing the transit line of each field. The goal of the survey was to extend the BD to declination -23 deg (a plan originally adopted by Argelander) with approximately the same magnitude limits, although the primary instrument was of larger aperture (159 mm) than the 78-mm telescope used for the BD. Thus, whereas the BD magnitude estimates extend to 9.4 mag with all fainter stars assigned a magnitude of 9.5, the SD magnitude estimates extend to 9.9 mag with all fainter stars assigned a magnitude of 10. The SD contains a number of stars fainter than 10.0 mag and even some as faint as 11 mag. Lists of all corrections made to the original data as a result of published corrigenda, stars deleted according to overstriking in the printed catalogs or their inclusion in lists of 'missing' stars, and stars inserted in later editions are given. No other corrections or changes have been incorporated into the original data, e.g., from more modern positions and magnitudes or from comparison with other catalogs.