File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file ident.dat 79 7732 Star identifications dists.dat 29 7732 Differences with modern positions piaref.dat 15 7698 Cross-mapping with the reference catalog pialac.dat 25 835 Cross-mapping with Lacaille's catalog piaflm.dat 21 2873 Cross-mapping with Flamsteed's catalog piahev_o.dat 21 2873 Cross-mapping with Hevelius's catalog -------------------------------------------------------------------------------- Byte-by-byte Description of file: ident.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- ZHr [0/23]? Hour part of the star designation (G1) 3 A1 --- Dot [.] Delimiter (G1) 4- 6 I3 --- ZNum ? Star number within the hour (G1) 7 A1 --- NoId [*] Asterisk if unidentified entry 8- 10 A3 --- BCon ? Bayer constellation 12- 14 A3 --- BLet ? Bayer letter 16 A1 --- BInd ? Bayer index 18- 20 A3 --- FCon ? Flamsteed constellation 22- 24 I3 --- FNum [1-141]? Flamsteed number 26- 29 I4 --- HR [1-9110]? Bright Star catalog number 30 A1 --- addHR [*] Next HR number included 31- 36 I6 --- HD [1-359083]? Henry Draper catalog number 37 A1 --- addHD [*] Next HD number included 38- 43 I6 --- HIP [1-120416]? Hipparcos catalog number 45- 50 I6 --- SAO [1-258997]? SAO catalog number 51 A1 --- addSAO [*] Next SAO number included 52- 55 A4 --- Com ? Component letter(s) 57- 61 F5.2 --- Mag ? Magnitude of match 62 A1 --- Shr [*] Asterisk if shared magnitude 63-105 A43 --- Name ? Star name of deep sky object designation -------------------------------------------------------------------------------- Byte-by-byte Description of file: dists.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- ZHr [0/23]? Hour part of the star designation (G1) 3 A1 --- Dot [.] Delimiter (G1) 4- 6 I3 --- ZNum ? Star number within the hour (G1) 7 A1 --- NoId [*] Asterisk if unidentified entry 8- 14 F7.2 arcmin dRA ? Difference in right ascension.cos(DE) (2) 16- 22 F7.2 arcmin dDE ? Difference in declination (2) 24- 29 F6.2 arcmin dist ? Distance from associated object (2) -------------------------------------------------------------------------------- Note (2): difference (HIP - Piazzi) of (SAO - Piazzi) if there is no HIP match, based on the identifications in ident.dat and positions in piazzi.dat. -------------------------------------------------------------------------------- Byte-by-byte Description of file: piaref.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- ZHr [0/23]? Hour part of the star designation (G1) 3 A1 --- Dot [.] Delimiter (G1) 4- 6 I3 --- ZNum ? Star number within the hour (G1) 8 A1 --- Status [=<>x*] status (G2) 10- 15 I6 --- RefNo ? Number in the reference catalog -------------------------------------------------------------------------------- Byte-by-byte Description of file: pialac.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- ZHr [0/23]? Hour part of the star designation (G1) 3 A1 --- Dot [.] Delimiter (G1) 4- 6 I3 --- ZNum ? Star number within the hour (G1) 8 A1 --- Status [=.) -------------------------------------------------------------------------------- Byte-by-byte Description of file: piaflm.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 2 I2 --- ZHr [0/23]? Hour part of the star designation (G1) 3 A1 --- Dot [.] Delimiter (G1) 4- 6 I3 --- ZNum ? Star number within the hour (G1) 8 A1 --- Status [= indicates that the Piazzi catalog entry includes the other catalog's entry, and more, x indicates that the Piazzi catalog entry has an identification, but no match in the other catalog, * indicates that the Piazzi catalog entry is unidentified. -------------------------------------------------------------------------------- History: * 2026-07-23: new revised edition. ================================================================================