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Description
The "Cape Photographic Durchmusterung" (CPD, Gill and Kapteyn 1895-1900) is a photographic survey of southern stars in the declination range -18 deg to -90 degrees. The original goal of the work was to carry out a southern survey similar to those of the "Bonner Durchmusterung" (BD, Argelander 1859-1862, see also Kuestner 1903) and Schoenfeld (1886) and the "Cordoba Durchmusterung" (CD, Thome 1892-1932) but using photographic plates which would provide a permanent record of the sky at the epoch of observation. The summary of the positional uncertainties quoted in the third volume of the published catalog gives +/- 0.28 sec (R.A.), +/- 0.044 arcmin (Dec.) for zones -18 to -57 degrees, +/- 0.157 sec + 0.0764/cos(delta) sec (R.A.), +/- 0.056 arcmin (Dec.) for zones -58 to -85 degrees, and +/- 0.157 sec + 0.0353/cos(delta) sec (R.A.), +/- 0.0127 arcmin (Dec.) for the polar plate where, as explained in the intro- duction to the third volume, many positions were derived from rectangular coordinates (these are positions reported to 0.1 sec (R.A.) and 0.001 arcmin (Dec.) in the -86 to -89 degree zones in the catalog). The probable error of a photographic magnitude, as determined by combining results for different magnitudes and weighting proportionately according to the numbers of stars in each class of magnitude, is given as +/- 0.055 mag. From an analysis of the faint magnitude limits on the plates discussed in the third volume introduction, the catalog as a whole can be considered complete to photographic magnitude 9.2, but it is stated that it will be found practically complete, in or near the Milky Way, to magnitude 9.5.
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