I/108 Cape Photographic Durchmusterung (Gill+ 1895-1900)

Cape Photographic Durchmusterung (CPD)

Gill D., Kapteyn J.C.

<Cape Photographic Durchmusterung, Ann. Cape Obs. 3 (1895, Part I: zones -18 to -37 degrees); 4 (1897, Part II: zones -38 to -52 degrees); 5 (1900, Part III: zones -53 to -89 degrees)>

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.

Introduction:

The complete catalog is contained in the data file, and corrections published in all errata have been made to the data. The machine version contains 454877 records, but only 454875 stars (two stars were later deleted, but their logical records are retained in the file so that the zone counts are not different from the published catalog).

A list of corrections made to the original data as a result of errata published in the three volumes is presented in cpchg.dat. No other corrections or changes have been incorporated into the original data, e.g., from more modern positions and magnitudes or comparison with other catalogs. The original ADC document contains the total number of stars in each declination zone and the number added and deleted in each zone.

Data are present for all stars in the catalog, including some which have been deleted in the errata; these have been flagged by a "D" in byte 11 of each respective record, but the records and data have been left in the machine version in order not to change the star counts and numerical sequencing and so that the stars appear in the correct locations if the catalog is sorted by right ascension.

File Summary:

Byte-by-byte Description of file: cpd.dat

Note on suppl:

a, b, or c: star is added in the corrigenda; D: star is deleted in the corrigenda

Note on mag:

20.0 = neb; 30.0 = var

Note on RAs:

precision varies; tenths can be blank

Note on DEm:

Only bytes 27-30 are used in zones north of -86 deg; the complete field is used for many stars on the polar plate.

Byte-by-byte Description of file: cpchg.dat

History:

The data in the machine-readable "Cape Photographic Durchmusterung" were keypunched directly from the published catalogs. The northern zones (-18 to -32 degrees and -35 degrees) were punched at Case Western Reserve University under the direction of B. N. Rappaport, who initiated the work and used the data as part of a project on the production of star charts by computer. However, only zones -18 through -26 degrees and -28 degrees had been verified and checked thoroughly, and some zones had not been completed. Mr. Rappaport was contacted and volunteered to continue the project and to oversee the punching and verifying of the remaining zones and those not verified and checked at Case. These zones were processed by a commercial firm with funding provided by the National Space Science Data Center, but all systematic checking of the completed zones was carried out by Mr. Rappaport on a volunteer basis. The zones were rechecked for counts and errata corrections, and the data reformatted to the standard DM catalog structure at the ADC by the author. The individual zones were then concatenated from disk data sets to a single magnetic tape file in CPD number order from north to south. Users should note that, due to corrections inserted from the errata, the CPD stars are not strictly in right ascension order within each zone; hence, if the catalog is sorted by right ascension, e.g., for search purposes, some CPD numbers will become disordered.

Acknowledgments:

This project owes its completion to the extensive work and striving for perfection of Barry Rappaport, who supervised the punching of all data, ran numerous machine and manual checks on completed zones, and prepared the preliminary tape of the finished catalog. The quality work of the keypunchers at Case Western Reserve University and Syntronix, Sherman Oaks, California is also greatly appreciated. The encouragement and support of the NSSDC Director, James I. Vette, made the completion of this project possible.

This document is based on the original ADC document prepared by Wayne H. Warren, Jr.

References:

Argelander, F. 1859-1862, Bonner Durchmusterung des Nordlichen Himmels, Erste bis dritte sektion, Astronomischen Beobachtungen auf der Sternwarte de Koniglichen Rhein. Friedrich-Wilhelm-Universitats zu Bonn, Bands 3-5.

Gill, D. and Kapteyn, J. C. 1895-1900, Cape Photographic Durchmusterung, Ann. Cape Obs. 3 (1895, Part I: zones -18 to -37 degrees); 4 (1897, Part II: zones -38 to -52 degrees); 5 (1900, Part III: zones -53 to -89 degrees).

Kuestner, F. 1903, Bonner Durchmusterung des Nordlichen Himmels, zweite berichtigte Auflage, Bonn Universitats Sternwarte (Bonn: A. Marcus und E. Weber's Verlag).

Schoenfeld, E. 1886, Bonner Sternverzeichniss, Vierte Sektion, Astronomische Beobachtungen auf der Sternwarte der Koniglichen Rheinischen Friedrich- Wilhelms-Universitat zu Bonn 8, Part IV (Bonn: Adolph Marcus).

Thome, J. M. 1892-1932, Cordoba Durchmusterung, Resultados del Observatorio Nacional Argentino 16 (1892, Part I: -22 to -32 degrees), 17 (1894, Part II: -32 to -42 degrees), 18 (1900, Part III: -42 to -52 degrees), 21 (Part I) (1914, Part IV, -52 to -62 degrees), 21 (Part II) (1932, Part V: -62 to -90 degrees).

(End) Nancy G. Roman [NSSDC/ADC] 12-Nov-1994