"Uranometria" is a star chart published by Johann Bayer (1572-1625) in 1603. A star chart of the southern sky is also included, but the star chart contains only magnitude of brightness and no location information. The number of stars is listed at the end of the North, Zodiac, and South charts, and the total number of stars drawn is usually the sum of them, 1706. However, following the number of stars in the south, there is "Haesuperioribus adiunetae numerum circiter 1725. (These are the upper parts connected therewith, the number of about 1725.)", And the total number including the stars in the north is 1725. Can be interpreted.
"Uranometria" is a star chart that summarizes the observation results of the position of stars created by 1600, but so far, there is no document that identifies the stars drawn in each star map. Based on the Linda Hall Library's Uranometria, the author identified the stars by reading their positions on the 49 charts below (although the charts on plates 42 and 43 are the same). In each chart, the "Uranometria" stars are drawn in red circles, the identified star positions are drawn in green circles, undrawn stars of grade 6.2 and above are drawn in blue circles, and nebulae are drawn in yellow. The center of the red and green circle is connected by a line, but a star with a long line has a large error. The Bayer code on the chart is the identification information for modern star catalogs and may differ from "Uranometria". The brightness of "Uranometria" is also a value judged by the author.
The total number of stars drawn on each chart was about 3570, and the number excluding duplicates was 1728. Therefore, the star catalog owned by Bayer contained the above 1725 stars. Also, if you look at the stars drawn on each chart, you can see that Bayer does not draw all the stars within the drawing range of the chart, but selects and draws them. For example, in the lower right corner of 12 Auriga, there is the Pleiades cluster, but it is not drawn.
(Note) Regarding the number of stars drawn in "Uranometria", the northern part of the chart (Triangulum (No.21)), the zodiac (Pisces (No.33)), and the southern part (Antarctic constellation (No.49)) )) At the end of the chart, there are 700 (699) stars, 445 stars, and 561 stars, respectively. The total is 1706 (1705) stars. The number of stars from 1st to 6th magnitude is 1380. These stars are numbered by the Bayer code, with the exception of the South Star (about 120). J. D. Warner (1979) p.18 states that Bayer sets the number of stars to "1706 + 325", which is incorrect because 325 stars are unnumbered star on the outer edge of the constellation. (1705=1380+325)I. Ridpath (2018) p.33 also assumes that the number of stars exceeds 2,000, but it is a similar error.
Catalogue of stars in "Uranometria"(1603) by Johann Bayer
References
I. Ridpath 「Star Tales (2nd edition)」Lutterworth Press (2018)
J. D. Warner 「The Sky Explored」Theatrum Orbis Terrarum (1979)
Star catalog for identification and reference formula for precession calculation
Myers J.R., Sande C.B., Miller A.C., Warren Jr. W.H., Tracewell D.A.
「SKY2000 Master Catalog, Version 5」A&A516,A26 (2006)
D. Hoffleit & W.H. Warren 「The Bright Star Catalogue, 5th rev.」 (1991)
J.Meeus 「Astronomical Algorithms (2nd Ver.)」Willmann-Bell inc. (1998)
