Construction of the Integrated Catalogue

The first step in constructing the integrated catalogue was to review each of the volumes of the Yale Zone Catalogues to determine which information was common to most volumes. These data were then extracted from the machine-readable versions and rewritten in a common format, with the addition of a running number for those zones that did not already have one and the number of the Yale volume and part. Data provided in many catalogues that were omitted included the precession terms, which are now easily computed when needed, and whether spectral or both spectral and central images were measured. Since the integrated version is in position order without regard to the declination zone, a code was added to indicate the particular catalogue that was used for the AG number. If the same star is listed in two overlapping zones, both entries are included. The duplication should be obvious from the data.

Because the original transcription was done on a computer without alphanumeric capability, various codes were employed to replace letters. These were changed back to the original letter values. Cmp and 300 were inserted in the spectra and magnitude fields to denote a composite spectrum and a variable magnitude, respectively. In some volumes, blends were indicated by placement of the data and were not properly indicated in the machine-readable files; these blends are now indicated in the notes.

In addition to the detailed notes in footnotes or the back of each volume, and the symbols following the star number, many volumes contain additional information in various columns of the records. With the exceptions noted above, this information was either added to the detailed notes or indicated by a code in byte 9 (see Table ). This often required that notes be added to provide multiple information. To save typing, the same codes were used in the notes as in the basic catalogue when appropriate.

The records in each volume were sorted by Durchmusterung number and examined both for duplicate DM numbers and for DM numbers that were out of right ascension order sufficiently to indicate an error. All such records were checked against the DM catalogues, and many errors were discovered and corrected. In the cases where duplicate DM numbers were valid, letters were added so that every DM number is unique in a given volume. (It is possible, although not probable, that one zone may contain two records with the same DM number while the overlapping zone will contain only one.)

Some printed volumes contain both visual and photographic magnitudes; some contain only one or the other; and some contain a color index with either one or two magnitudes. If only a single magnitude is printed, it is used in this machine-readable version and the field for the missing magnitude is blank. If one magnitude and a color index are given, they are used to compute the missing magnitude. If both magnitudes and a color index are given in the printed version, the color index is ignored.

Trans. Astron. Obs. Yale Univ. 23 contains addenda to earlier volumes. Sections A, B, E, and F had been included on the original tapes; the spectra in sections C and D were added in this processing.

In the printed volume of Trans. Astron. Obs. Yale Univ. 32, Part II, many of the magnitudes clearly are unreasonable. Most of the stars for which this is true are variable. They have been so marked in the catalogue and the variable star name has been given in the notes. For the few stars that are not obviously variable, the magnitudes have been taken from SIMBAD.

Although an attempt has been made to make the catalogue, its related files, and this document adequate for many purposes, the introduction to each of the Yale Zone Catalogues contains a substantial amount of additional information. It is recommended that the user who wishes to understand the catalogue in greater detail refer to these introductions.