Sky & Telescope - February 2023 - 27

omission, since accurate maps of the southern sky would be
essential to ships navigating in the far southern oceans.
Charting the Southern Sky
Plancius began filling in this celestial void in 1589 when he
added a constellation he called Crux (south of Eridanus)
and another designated Triangulus Antarcticus (near the
south celestial pole). Sailors and explorers such as Andrea
Corsali, Amerigo Vespucci, and Francisco de Medina had
previously reported the stars in these groupings - but they
lacked accurate coordinates. Plancius folded them into
new constellations, which he placed in distinctly different
locations than our current Crux and Triangulum Australe.
In 1592, Plancius added two more southern constellations:
Columba, the Dove, and Polophilax, the Guardian of the
Pole. Columba is the first truly non-Ptolemaic constellation
to have survived. (German cartographer Caspar Vopel introduced
Coma Berenices and Antinous in 1536, but Ptolemy
had previously described these, though he didn't treat them
as separate constellations.)
Plancius set about improving knowledge of the southern
sky by training several Dutch sailors and navigators, including
Pieter Dirkszoon Keyser and Frederick de Houtman.
Tasked with making accurate celestial observations during
their voyages, Keyser and de Houtman provided coordinates
for more than 120 southern stars. Based on their efforts,
in 1598 Plancius collaborated with a local cartographer to
produce a celestial globe that included a whole new southern
menagerie. He retained Columba and introduced 12 new
figures: Apis, Apus, Chamaeleon, Dorado, Grus, Hydrus,
Indus, Pavo, Phoenix, Tucana, Triangulum Australe, and
Volans. To these, Plancius also added Crux, today's familiar
Southern Cross - Ptolemy's asterism south of Centaurus.
Apis (the Bee) quickly morphed into Musca (the Fly). This
Musca appeared as early as 1603 on a globe designed by
Dutch cartographer Willem Janszoon Blaeu and has survived
to the present. Apis, however, did reappear from time to time,
including on German astronomer Johann Gabriel Doppelmayr's
planisphere of 1741, where the constellation was
labeled " Musca Apis. " As we'll see later, Plancius introduced
another bee, this time in the Northern Hemisphere.
These new figures were apparently intended to honor discoveries
by recent explorers. Some historians seem unsure as
to whether it was Keyser, de Houtman, or Plancius who bundled
these stars into constellations. But Plancius did include
drawings of a toucan, a bird of paradise, and a chameleon on
a terrestrial map dated 1594, which strongly argues in favor of
the idea that their celestial counterparts were his creations.
Regardless of their origins, Bayer embraced these new
constellations in Uranometria, his highly influential celestial
atlas of 1603. Largely as a result of Bayer's exclusion, celestial
cartographers quickly abandoned Polophilax, Triangulus
Antarcticus, and the version of Crux south of Eridanus. Of
the 17 constellations Plancius introduced prior to 1600,
fourteen are still in use today. It appears that following this
Plancius Constellations
Constellation
Apes (Northern Musca)
Apis (Southern Musca)
Apus
Camelopardalis
Cancer Minor
Chamaeleon
Columba
Crux (below Centaurus)
Crux (south of Eridanus)
Dorado
Gallus
Grus
Hydrus
Indus
Jordanus Fluvius
Monoceros
Pavo
Phoenix
Polophilax
Sagitta Australis
Tigris Fluvius
Triangulum Antarcticus
Triangulum Australe
Tucana
Volans
Original Source
1612 globe
1598 globe
1598 globe
1612 globe
1612 globe
1598 globe
1592 map
1598 globe
1589 globe
1598 globe
1612 globe
1598 globe
1598 globe
1598 globe
1612 globe
1612 globe
1598 globe
1598 globe
1592 map
1612 globe
1612 globe
1589 globe
1598 globe
1598 globe
1598 globe
Status
Last appearance 1899
Adopted by IAU
Adopted by IAU
Adopted by IAU
Last appearance 1660
Adopted by IAU
Adopted by IAU
Adopted by IAU
Last appearance 1607
Adopted by IAU
Last appearance 1660
Adopted by IAU
Adopted by IAU
Adopted by IAU
Last appearance 1730
Adopted by IAU
Adopted by IAU
Adopted by IAU
Last appearance 1607
Last appearance 1660
Last appearance 1730
Last appearance 1607
Adopted by IAU
Adopted by IAU
Adopted by IAU
burst of activity, Plancius took a break from cartography. But
he wasn't quite finished.
Constellations of 1612
In 1612, Plancius, in collaboration with Flemish globe-maker
Pieter van den Keere, produced a celestial globe on which he
introduced eight new constellations. Many of these filled gaps
in the northern sky. They included Apes (a bee, the northern
counterpart to his Apis from 1598), Camelopardalis, Cancer
Minor, Gallus (a rooster surrounded by Monoceros, Canis
Major, and Argo Navis), Jordanus Fluvius (the Jordan River),
Monoceros (the Unicorn), Sagitta Australis (the Southern
Arrow), and Tigris Fluvius (the Tigris River).
Two of these new constellations, Camelopardalis (the
Giraffe) and Monoceros, were immediately popular and
appeared on just about every subsequent celestial chart and
are included in the IAU's official list. The other six didn't
survive, but most managed to persist for decades. Although
they're not familiar to today's stargazers, 17th-century
astronomers knew them well. Let's trace them out.
sk yand tele scope .o r g * FEBRUARY 2023 27
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Sky & Telescope - February 2023

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