This constellation, tucked awkwardly between Ophiuchus and Aquila and overlapped by the tail of Serpens, was originated in 1777 by Martin Poczobut, director of the Royal Observatory at Vilna (now Vilnius, Lithuania). He invented it to honour his king, Stanisław August Poniatowski, who was monarch of both Poland and Lithuania. King Stanisław was a noted patron of the arts and sciences, and the bull was a feature of his family’s coat of arms.
Poczobut published a catalogue of 16 component stars in Cahiers des observations astronomiques faites à l’observatoire royal de Vilna en 1773 (published 1777); this list was reprinted for wider consumption by Johann Bode in his Astronomisches Jahrbuch for 1785. The constellation was first depicted in 1778 as le Taureau Royal de Poniatowski in a revised reprint of Jean Fortin’s Atlas Céleste. The name was later Latinized to Taurus Poniatovii by Bode on his Uranographia of 1801 (see illustration below).
The head of the bull incorporated five stars that Ptolemy had listed in his Almagest as lying outside Ophiuchus. Four of these, along with some fainter neighbours, form a V-shaped group between the right shoulder of Ophiuchus and the tail of Serpens. This group reminded Poczobut of the Hyades cluster that outlines the face of Taurus the bull in the zodiac. The fifth Ptolemaic star, which we now know as 72 Ophiuchi, lay on the bull’s right horn and was the brightest star of the constellation, magnitude 3.7.
Poczobut did not realize it, but his short-lived creation contained the faint red dwarf known as Barnard’s Star, the second-closest star to the Sun. It lies near the present-day 66 Ophiuchi. The stars of Taurus Poniatovii are now part of Ophiuchus and Serpens Caput.
Taurus Poniatovii, lying above the tail of Serpens, the serpent, pictured in the Uranographia of Johann Bode (1801). The face of the bull is marked by a V-shaped group of stars that resembles the Hyades cluster in Taurus, the zodiacal bull.
© Ian Ridpath. All rights reserved