Surveys with small optical telescopes

odern astrophysics owes its existence to small-telescope surveys dating back to the 18th century, for example Flamsteed (1725). In the 19th century, Argelander’s survey based on visual observations with small telescopes and meridian circles culminated in the 1859 publication of the Bonner Durchmusterung (BD), a catalogue of northern hemisphere stars brighter than ninth magnitude, with accompanying charts (Batten 1991). The BD catalogue was later extended to the southern hemisphere by the Córdoba Durchmusterung (CD; 1892 onwards) prepared using Argelander’s method, and the Cape Photographic Durchmusterung (CPD; 1885onwards) based on photographic plates