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J/A+A/544/A31       Star catalogues of Ptolemaios, Ulugh Beg    (Verbunt+, 2012)

The star catalogues of Ptolemaios and Ulugh Beg. Verbunt, F., van Gent, R.H. <Astron. Astrophys. 544, A31 (2012)> =2012A&A...544A..31V
ADC_Keywords: Historical catalog ; Positional data Keywords: astrometry - history and philosophy of astronomy Abstract: In late antiquity and throughout the middle ages, the positions of stars on the celestial sphere were obtained from the star catalogue of Ptolemaios. A catalogue based on new measurements appeared in 1437, with positions by Ulugh Beg, and magnitudes from the 10th-century astronomer al-Sufi. We provide machine-readable versions of these two star catalogues, based on the editions by Toomer (1998) and Knobel (1917), and determine their accuracies by comparison with the modern Hipparcos Catalogue. The magnitudes in the catalogues correlate well with modern visual magnitudes; the indication `faint' by Ptolemaios is found to correspond to his magnitudes 5 and 6. Gaussian fits to the error distributions in longitude/latitude give widths sigma ∼27-arcmin/23-arcmin in the range |Δλ,Δβ|<50-arcmin for Ptolemaios and σ∼22-arcmin/18-arcmin in Ulugh Beg. Fits to the range |Δλ,Δβ<100-arcmin gives 10-15 per cent larger widths, showing that the error distributions are broader than gaussians. The fraction of stars with positions wrong by more than 150-arcmin is about 2 per cent for Ptolemaios and 0.1 percent in Ulugh Beg; the numbers of unidentified stars are 1 in Ptolemaios and 3 in Ulugh Beg. These numbers testify to the excellent quality of both star catalogues (as edited by Toomer and Knobel). Description: We present Machine-readable versions of the star catalogues of Ptolemaios (137) and Ulugh Beg (1437). In addition to the data from the historical catalogues, the machine-readable version contains the modern identification with a Hipparcos star and the latter's magnitude, and based on this identification the positional accuracy. For Ulugh Beg's catalogue we also give cross references to the catalogue of Ptolemaios. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file ptolema.dat 78 1028 Star Catalogue of Ptolemaios (137) ulughbeg.dat 88 1018 Star Catalogue of Ulugh Beg (1437)
See also: V/61 : Almagest (Ptolemy's Star Catalog) J/A+A/516/A28 : Star catalogue of Tycho Brahe (1627) (Verbunt+, 2010) J/A+A/516/A29 : Star catalogue of Hevelius (1690) (Verbunt+, 2010) J/A+A/530/A93 : de Houtman, Kepler and Halley star catalogs (Verbunt+ 2011) Byte-by-byte Description of file: ptolema.dat
Bytes Format Units Label Explanations
1- 4 I4 --- P [1/1028] Sequence number in Ptolemaios Catalogue 6- 7 I2 --- C [1/48] Constellation sequence number 9- 12 A4 --- cst Abbreviation of constellation name 14- 15 I2 --- N [1/45] Sequence number of star in constellation 16 A1 --- f_N [a] 'a' for star outside the constellation figure 19- 20 I2 30deg Elon.Z [1/12] Zodiacal sign of longitude (1) 22- 23 I2 deg Elon.d [0/30] Longitude (degrees) (1) 25- 26 I2 arcmin Elon.m [0/59] Longitude (arcmin) (1) 29- 30 I2 deg Elat.d [0/90] Ecliptic latitude (degrees) (2) 32- 33 I2 arcmin Elat.m [0/60] Ecliptic latitude (arcmin) (2) 35 A1 --- Elat.- [AB] Sign of latitude (2) 38 I1 --- VP [1/9] Magnitude as given by Ptolemaios (3) 39 A1 --- q_VP [bf] brighter/fainter qualifier by Ptolemaios (G1) 41- 46 I6 --- HIP ?=0 Hipparcos number of identification 48 I1 --- I [1/6] Quality of identification flag (G2) 50 I1 --- T [0/3] Comparison flag with Toomer (4) 52- 55 F4.1 mag Vmag Johnson V magnitude (from Hipparcos) 57- 62 F6.1 arcmin Dl Difference in longitude (Hipparcos-Ptolemaios) 64- 69 F6.1 arcmin Db Difference in latitude (Hipparcos-Ptolemaios) 71- 76 F6.1 arcmin dist Distance Δ between Ptolemaios and Hipparcos positions 78 A1 --- Flag [*] Flag for annotation in article
Note (1): The longitude is given by Elon =(Elon.Z-1)*30+Elon.d+Elon.m/60 (assumed Equinox=-128, corresponding to Hipparchos observations) Note (2): The latitude is given by Elat=Elat.d+Elat.m/60 for boreal stars ('B' in Elat.-); the sign of the latitude is changed for austral stars ('A' in Elat.-). Note (3): Special values: 7=faint, 9=nebulous Note (4): Comparison flag with Toomer as follows: 1 = same identification in Toomer 2 = identification in Toomer is one of two plausible identifications 3 = identification in Toomer is incompatible with ours
Byte-by-byte Description of file: ulughbeg.dat
Bytes Format Units Label Explanations
1- 4 I4 --- U [1/1018] Sequence number in Ulugh Beg Catalogue 5 A1 --- n_U [c] 'c' when the position is derived from Ptolemaios via al-Sufi 7- 10 I4 --- P Corresponding sequence number of in Ptolemaios 13- 14 I2 --- C Sequence number of constellation 16- 19 A4 --- cst Abbreviation of constellation name 21- 22 I2 --- N Sequence number of star in constellation 23 A1 --- n_N [a] 'a' for star outside the constellation figure 26- 27 I2 30deg Elon.Z [0/11] Zodiacal sign (1) 29- 30 I2 deg Elon.d Degrees of longitude (1) 32- 33 I2 arcmin Elon.m Minutes of longitude (1) 37- 38 I2 deg Elat.d Degrees of ecliptic latitude (2) 40- 41 I2 arcmin Elat.m Arcminutes of ecliptic latitude (2) 43 A1 --- Elat.- Sign of latitude (2) 46 I1 --- VU Magnitude as given by Ulugh Beg (3) 47 A1 --- q_VU [bf] brighter/fainter qualifier by Ulugh Beg (G1) 49- 54 I6 --- HIP ?=0 Hipparcos number of identification 56 I1 --- I Flag indicating quality of identification (G2) 58 I1 --- K [0/3] Comparison flag with Knobel (4) 60 I1 --- I-P [0/3] Comparison flag with Ptolemaios (5) 62- 65 F4.1 mag Vmag Johnson V magnitude (from Hipparcos) 67- 72 F6.1 arcmin Dl Difference in longitude (Hipparcos-UlughBeg) 74- 79 F6.1 arcmin Db Difference in latitude (Hipparcos-UlughBeg) 81- 86 F6.1 arcmin dist Distance {Dleta} between UlughBeg and Hipparcos positions 88 A1 --- Flag [*] Flag for annotation in article
Note (1): The longitude is given by Elon =(Elon.Z)*30+Elon.d+Elon.m/60 (Equinox=1437) Note (2): The latitude is given by Elat=Elat.d+Elat.m/60 for boreal stars ('B' in Elat.-); the sign of the latitude is changed for austral stars ('A' in Elat.-). Note (3): Special values: 8=not seen, 9=nebulous Note (4): Comparison flag with Knobel as follows: 0 = unidentified in Knobel 1 = same identification in Knobel as ours 2 = identification in Knobel is one of two plausible identifications 3 = identification in Knobel is incompatible with ours Note (5): Comparison flag with Ptolemaios as follows: 0 = corresponding star in Ptolemaios is unidentified 1 = corresponding star in Ptolemaios has same identification 2 = corresponding star in Ptolemaios has alternative identification 3 = corresponding star in Ptolemaios has different identification
Global notes: Note (G1): Qualifier as follows: f = somewhat fainter b = somewhat brighter Note (G2): Quality of identification flag as follows: 1 = secure identification with nearest star 2 = secure identification, even though not nearest star 3 = probable identification 4 = possible identification 5 = not identified 6 = repeated entry
Acknowledgements: Frank Verbunt, Dept.Astrophysics Radboud University Nijmegen F.Verbunt(at)astro.ru.nl
(End) Frank Verbunt [Radboud Univ. Nijmegen], Patricia Vannier [CDS] 05-Jun-2012
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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