J/A+A/649/A112 The star catalogue of Wilhelm IV (Verbunt+, 2021)
The star catalogue of Wilhelm IV, Landgraf von Hessen-Kassel.
Accuracy of the catalogue and of the measurements.
Verbunt F., Schrimpf A.
<Astron. Astrophys. 649, A112 (2021)>
=2021A&A...649A.112V 2021A&A...649A.112V (SIMBAD/NED BibCode)
ADC_Keywords: Historical catalog ; Positional data
Keywords: astrometry - history and philosophy of astronomy
Abstract:
We analyse a manuscript star catalogue by Wilhem IV, Landgraf von
Hessen-Kassel from 1586. From measurements of altitudes and of angles
between stars, given in the catalogue, we find that the measurement
accuracy averages 26 arcsec for eight fundamental stars, compared to
49 arcsec of the measurements by Brahe. The computation in converting
altitudes to declinations and angles between stars to celestial
position is very accurate, with errors negligible with respect to the
measurement errors. Due to an offset in the position of the vernal
equinox the positional error of the catalogue is slightly worse than
that of Brahe's catalogue, but when correction is made for the offset
-- which was known to 17th century astronomers -- the catalogue is
more accurate than that of Brahe. We provide machine-readable Tables
of the catalogue.
Description:
We present a Machine-readable version of the star catalogue of Wilhelm
IV (1586). In addition to the data from the Historical catalogue, 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.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
wilhiv.dat 171 387 Positions in Star Catalogue of Wilhelm IV
(WilhelmIV, table 5)
wilhivdi.dat 73 500 Angular distances in the Star Catalogue
(WilhelmIV-Dist, table 6)
wilhival.dat 30 378 Altitudes in Star the Catalogue
(WilhelmIV-Alt, table 7)
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See also:
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
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: wilhiv.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- W Sequence number in Wilhelm IV Catalogue
6- 7 I2 --- C Sequence number of constellation
9- 11 A3 --- Con Abbreviation of constellation name
13- 14 I2 --- i Sequence number of star in constellation
17- 19 I3 deg RAd ? Degrees of right ascension (1)
21- 22 I2 arcmin RAm ? Arcminutes of right ascension (1)
24- 25 I2 arcsec RAs ? Arcseconds of right ascension (1)
28- 29 I2 deg DEd ? Degrees of declination (2)
31- 32 I2 arcmin DEm ? Arcminutes of declination (2)
34- 35 I2 arcsec DEs ? Arcseconds of declination (2)
37 A1 --- DE- [MS] sign of declination (2)
40- 41 I2 30deg Elon.Z [1/12] Zodiakal sign of ecliptic longitude (3)
43- 44 I2 deg Elon.d Degrees of ecliptic longitude (3)
46- 47 I2 min Elon.m Minutes of ecliptic longitude (3)
49- 50 I2 sec Elon.s Seconds of ecliptic longitude (3)
53- 54 I2 deg Elat.d Degrees of ecliptic latitude (4)
56- 57 I2 arcmin Elat.m Arcminutes of ecliptic latitude (4)
59- 60 I2 arcsec Elat.s Arcseconds of ecliptic latitude (4)
62 A1 --- Elat.- [SM] Sign of ecliptic latitude (4)
65 I1 mag VW Magnitude as given by Wilhelm IV
67- 72 I6 --- HIP ?=0 Hipparcos number of identification
75 I1 --- I Flag indicating quality of identification (5)
77- 80 F4.1 --- Vmag Magnitude of Hipparcos identification
82- 87 F6.1 arcmin DRA Difference in right ascension: Wilhelm IV-HIP
89- 94 F6.1 arcmin DDE Difference in declination: Wilhem IV-HIP
96-101 F6.1 arcmin Deltac Angle between corrected Wilhelm IV and HIP
103-108 F6.1 arcmin Dlon Difference in longitude: Wilhelm IV-HIP
110-115 F6.1 arcmin Dlat Difference in latitude: Wilhem IV-HIPPARCOS
117-122 F6.1 arcmin Delta Uncorrected offset between Wilhelm IV and HIP
124-171 A48 --- Descr Name or description of star
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Note (1): The right ascension in degrees is given by
ra = RAd + RAm/60 + RAs/3600
Note (2): The declination in degrees is given by
dec = ±(DEd + DEm/60 + DEs/3600); ± for DE-=S/M
Note (3): The ecliptic longitude in degrees is given by
lambda=(Elon.z-1)30+Elon.d+Elon.m/60+Elon.s/3600
Note (4): the ecliptic latitude is given by
beta = ±(Elat.d+Elat.m/60+Elat.s/3600); ± for Elat.- = S/M
Note (5): Flag indicating quality of identification as follows:
1 = secure identification with nearest star
2 = secure identification, even though not nearest star
3 = identified with merger of stars
6 = double entry
9 = nebulous
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Byte-by-byte Description of file: wilhivdi.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- W Sequence number in Wilhelm IV Catalogue
5- 7 I3 --- WR Sequence number of reference star
9 I1 --- F [0/2] Flag for repeat entry (1)
12- 13 I2 deg phi.d Degrees of angle between
star and reference star (2)
15- 16 I2 arcmin phi.m Arcminutes of angle between
star and reference star (2)
18- 19 I2 arcsec phi.s Arcseconds of angle between
star and reference star (2)
21- 25 F5.1 arcmin dphi Difference catalogue angle and HIP value,
phi - phi_HIP
28- 59 A32 --- Refer Name or description of reference star
61- 66 I6 --- HIP ?=0 HIPPARCOS number of entry
68- 73 I6 --- HIPr HIPPARCOS number of reference star
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Note (1): Flag for repeat entry as follows:
0 = not repeated or reverse repeated entry
1 = repeated entry
2 = reverse repeated entry: W and ER switched
Note (2): The angle between star and reference star in degrees is given by
ra = phi.d + phi.m/60 + phi.s/3600
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Byte-by-byte Description of file: wilhival.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- W Sequence number in Wilhelm IV Catalogue
5 I1 --- F [0/1] flag for repeated entry (1)
8- 9 I2 deg h.d Degrees of altitude (2)
11- 12 I2 arcmin h.m Arcminutes of altitude (2)
14- 15 I2 arcsec h.s Arcseconds of altitude (2)
17 A1 --- U [SIM] flag indicating nature of altitude (3)
19- 23 F5.1 arcmin dh Difference altitude with altitude from HIP,
h - h_HIP
25- 30 I6 --- HIP ?=0 HIPPARCOS number of entry
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Note (1): Flag for repeated entry as follows:
0 = not repeated entry
1 = repeated entry
Note (2): Altitude in degrees is h.d+h.m/60+h.s/3600
Note (3): Flag indicating nature of altitude as follows:
S = northern superior meridional passage
I = northern inferior meridional passage
M = southern meridional passage
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Acknowledgements:
Frank Verbunt, f.verbunt(at)astro.ru.nl
IMAPP, Radboud University Nijmegen, Netherlands
(End) Frank Verbunt [IMAPP, Netherlands], Patricia Vannier [CDS] 05-Mar-2021