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J/other/JHA/47.294      Ilkhanid star table (1232)             (Mozaffari, 2016)

A medieval bright star table: the non-Ptolemaic star table in the Ilkhani Zij. Mozaffari S.M. <Journal for the History of Astronomy, 47, 294-316 (2016)> =2016JHA....47..294M (SIMBAD/NED BibCode)
ADC_Keywords: Historical catalog ; Positional data Keywords: Maragha observatory - Ilkhani zij - Islamic astronomy - medieval astronomy - star table - Ptolemy - Almagest Abstract: The Ilkhani zij compiled by Nasir al-Din al-Tusi and his colleagues in the first period of the astronomical activities (the 1260s and early 1270s) in the Maragha observatory includes a star table collecting important observations of Islamic astronomers from the early ninth century through the third quarter of the thirteenth century, including the Mumtahan astronomers, Ibn al-A'lam, Ibn Yunus, as well as the Maragha astronomers themselves. This table gives the ecliptical coordinates of 18 bright stars in comparison with Ptolemy's corresponding values. This medieval bright star table is especially interesting for two reasons: first, it provides reliable evidence for the examination of the accuracy of the observations made and the instruments employed (notably, an armillary sphere) in the Maragha observatory. Second, it facilitates a comparative study of the accuracy of stellar observations in medieval Middle Eastern astronomy in the period in question. We have obtained the result that the Maragha astronomers observed more accurate star longitudes than did their predecessors, while for the latitudes, all Islamic observers appear to have gained about the same degree of accuracy. We also discuss two delicate matters raised by this table: first, the problem of the use of the two different values for the rate of precession by the Maragha astronomers in order to convert earlier star longitudes to the epoch of the Ilkhani zij (1°/66 years for Ptolemy's longitudes and 1°/70 years for those measured by their Islamic predecessors); second, the change in the star latitudes essentially related to the various values measured by Ptolemy and the Islamic astronomers represented side-by-side in it. Finally, we briefly discuss a small celestial globe designed by the son of Mu'ayyad al-Din al-'Urdi, the instrument-maker of the Maragha observatory. Description: We present machine-readable version of the bright star table of the Ilkhanid astronomical table (1232). It contains the ecliptic coordinates of the 16 stars from this historical table, their modern identification with Bayer designation, and the modern coordinates computed on the basis of the Bright Star Catalogue for the time. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file margha01.dat 38 16 The Ilkhani bright star table
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) J/A+A/544/A31 : Star catalogues of Ptolemaios, Ulugh Beg (Verbunt+, 2012) Byte-by-byte Description of file: margha01.dat
Bytes Format Units Label Explanations
1- 2 I2 --- IZ [1/16] Sequence number in the non-Ptolemaic star table in the Ilkhani zij 4- 10 A7 --- Name Bayer designation and abbreviation of constellation name 12- 14 I3 deg Elono.d [0/360] Degrees of the ecliptic longitude as given in the non-Ptolemaic star table in the Ilkhani zij (1) 16- 17 I2 arcmin Elono.m [0/59] Minutes of the ecliptic longitude as given in the non-Ptolemaic star table in the Ilkhani zij (1) 19 A1 --- Elato.- [±] Sign of ecliptic latitude as latitude as given in the non-Ptolemaic star table in the Ilkhani zij (1) 20- 21 I2 deg Elato.d [0/90] Degrees of the ecliptic latitude as given in the non-Ptolemaic star table in the Ilkhani zij (1) 23- 24 I2 arcmin Elato.m [0/59] Minutes of the ecliptic longitude as given in the non-Ptolemaic star table in the Ilkhani zij (1) 26- 28 I3 deg Elon.d [0/360] Degrees of the ecliptic longitude as computed from the bright star catalogue for 18 January 1232 AD 30- 31 I2 arcmin Elon.m [0/59] Minutes of the ecliptic longitude as computed from the bright star catalogue for 18 January 1232 AD 33 A1 --- Elat.- [±] Sign of ecliptic latitude as computed from the bright star catalogue for 18 January 1232 AD 34- 35 I2 deg Elat.d [0/90] Degrees of the ecliptic latitude as computed from the bright star catalogue for 18 January 1232 AD 37- 38 I2 arcmin Elat.m [0/59] Minutes of the ecliptic latitude as computed from the bright star catalogue for 18 January 1232 AD
Note (1): The variants given for the ecliptic coordinates in the preserved manuscripts of the Ilkhani zij are presented on page 298 of the paper.
Acknowledgements: S. Mohammad Mozaffari, mozaffari(at)riaam.ac.ir
(End) S.M. Mozaffari [RIAAM, IRAN], Patricia Vannier [CDS] 09-Nov-2017
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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