View source for Category:88 IAU-Constellations

[[File:IAU logo.svg|alt=IAU Logo|thumb]]

== History ==

Over the course of the decade of the 1920s, the IAU officially defined the borders of the constellations as lines of constant right ascension and declination (for the equator and equinox of [https://en.wikipedia.org/wiki/Epoch_(astronomy)#Besselian_years B1875.0]). This definition is used as international standard in research papers.

However, there is no single date of the definition but there are actually some very important dates:

# 1922 The international standardization of 89 Latin constellation names:
## in nominative and genitive forms and their three-letter-abbreviations. 
## the defunct constellation Argo (Arg) was also included for historical reasons.
# 1925 Delporte's presentation of his definition of border lines. 
# 1928 the acceptance of Delporte's suggestion. 
# 1930 publication of Delporte's delineation of the constellation boundaries<ref>Eugène Joseph Delporte, ''Délimitation scientifique des constellations (tables et cartes)'' (Cambridge: Cambridge University Press, 1930) [[https://historiadelaastronomia.wordpress.com/wp-content/uploads/2023/05/delporte.pdf online link]].</ref> with an accompanying celestial atlas.<ref>Eugène Joseph Delporte, ''Atlas céleste'' (Cambridge: Cambridge Unibversity Press, 1930) -- reprinted in 2013 by Cambridge University Press.</ref>

The [[IAU-Constellations Origins|origins of these constellations]] are diverse.

== Constellation from a given position ==

Algorithms for determining the IAU constellation from a given celestial position were published by Roman<ref>Nancy G. Roman, "Identification of a Constellation from a Position", ''Publications of the Astronomical Society of the Pacific'', '''99''' (1987), 695-699 [[https://ui.adsabs.harvard.edu/abs/1987PASP...99..695R/abstract ADS link] / [https://www.jstor.org/stable/40678983 JSTOR link]].</ref> and Glaschke.<ref>Patrick Glaschke, "Fast Determination of Constellation Membership", eprint arXiv:1008.3966 (2010) [[https://ui.adsabs.harvard.edu/abs/2010arXiv1008.3966G/abstract ADS link]].</ref>

== Constellation areas ==

Following Delporte's publication of the IAU constellation boundaries independent computations of the constellation areas, expressed in square degrees (deg<sup>2</sup>), were published in 1934 by Levin<ref>Arthur Everard Levin, "Areas of the Constellations", ''Astronomical Association Handbook for 1935'' (London: Astronomical Association, 1934), pp.&nbsp;34-35 [[https://webspace.science.uu.nl/~gent0113/downloads/wgsn/levin_1934.pdf online link]] -- reprinted in the ''Handbook of the British Astronomical Association for 1972'' (London: British Astronomical Association, 1971), pp.&nbsp;65-66.</ref> and in 1937 by Brocchi.<ref>Dalmero Francis Brocchi, "Constellations", ''Popular Astronomy: A Review of Astronomy and Allied Sciences'', '''45''' (1937), 130-134 [[https://ui.adsabs.harvard.edu/abs/1937PA.....45..130B/abstract ADS link]].</ref> Both authors give the constellation areas to the nearest 0.001 deg<sup>2</sup> but occasionally differ by one unit in the last significant place.<ref>Online data appear to be based on Levin's computations.</ref>

== Weblinks ==
* Ian Ridpath [http://www.ianridpath.com/constellations1.html Constellations Andromeda–Indus]
* Ian Ridpath [http://www.ianridpath.com/constellations2.html Constellations Lacerta–Vulpecula]
* Ian Ridpath [http://www.ianridpath.com/boundaries.html Constellation boundaries]
* Ian Ridpath [http://www.ianridpath.com/iaulist1.html The IAU list of constellations]
* Ian Ridpath [http://www.ianridpath.com/iaulist2.html The IAU list of four-letter constellaiton abbreviations]

== References ==

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