Sky & Telescope - March 2020 - 29

WILLY POG ÁN Y

that Lacaille invented contains a star
brighter than 3rd magnitude, and
precious few even reach 4th magnitude. He reserved all the bright stars to
glorify the constellations invented by
the Dutch. He even appended 1.7-magnitude Miaplacidus (Beta Carinae) to
Greater Argo, when he could easily have
used it for purposes of his own had he
desired to do so.
Bayer had done a rather haphazard
job with the far-southern sky, based
on unreliable sources, so Lacaille also
re-lettered the far-southern constellations. If you see a Greek letter for
a star south of declination -30°, it
almost certainly comes from Lacaille
rather than Bayer. When he came to
Greater Argo Navis, Lacaille understandably ran out of letters. Even in this article, which mentions only a few selected
bright stars, we have used about half the Greek alphabet.
Bayer's practice after running out of Greek letters was to
continue with lowercase Roman letters. But Lacaille was
greedy; he noted that Greater Argo contains more than
160 stars readily visible to the unaided eye, and contrary to
Bayer's practice, he insisted on giving letters to each. So he
subdivided his Navire (French for ship) into "la Pouppe, le
Corps & la Voilure," meaning the Poop, the Body, and the
Sails. Then he ran through the Roman alphabet, both lower
case and upper, for each subdivision.
Incidentally, Carina can mean both a ship's keel and its
entire structure; Lacaille's use of "Corps" makes it clear that
he meant the latter. So it's more accurate to translate Carina
as the Hull than the more usual Keel.
I think that Lacaille was showing off. Sure, he saw a lot
more stars in Argo than Ptolemy had, but he had the beneﬁt
of a telescope. And it's dramatically much easier to see a faint
object without optical aid if you have a telescope handy to
reassure you that it's not an optical illusion.
You can see the results in the table at the bottom of
page 28. Canopus, being one of the 24 truly splendid stars,
rates a Greek letter as the Alpha star "du Navire" (of the
Ship). Four entries later we have the G star of "Pouppe du
Navire," the Poop of the Ship.
Things change a little in the Latin version of 1763. Now
each one of the stars has a constellation listed, not just the
ones that have letters. That means that unlike both Ptolemy
and Bayer, Lacaille had completely tiled the sky with constellations, leaving no gaps between them. But in both the
French and Latin versions, Lacaille never uses the terms Poop,
Hull, and Sail without also saying "of the Ship." And letterless
stars are assigned to Argo, not to its subdivisions.
Nomenclature changes yet again in the 1847 catalog. Now
"of the Ship" has been dropped, and Puppis, Carina, and Vela
are treated as full-ﬂedged constellations. To drive the point

THE VOYAGE
OF THE ARGO
The constellation that Ptolemy
called Argo Navis was associated with several different ships in
ancient history, but most GrecoRoman authors agreed that it was
Jason's Argo. The Argonauts who
sailed aboard it included Hercules,
Castor, Pollux, Orpheus, and all
the other great heroes alive at that
time. They sailed to Colchis, in
what is now the country Georgia,
to retrieve the fleece of the golden
ram that ended up in the sky as
the constellation Aries. The painting above by Willy Pogány is from Padraic Colum's
children's book The Golden Fleece and the Heroes
Who Lived Before Achilles, still in print almost a century after first publication.
The most memorable character in the Argo legend
is the sorceress Medea, daughter of King Aeëtes,
owner of the Golden Fleece. She betrays her father for
love of Jason, who in turn betrays Medea after they
return home to Greece. In one version of the story Jason loses everything that he owns and dies when the
prow of the rotting Argo falls on him as he sits under it
contemplating his past glory.

home, letterless stars are assigned to the components, not to
Argo itself. But the Greek-letter stars are still "of Argo."
Affairs remained much like that for the next 80 years;
both Argo Navis and its constituent parts coexisted uneasily, with different authors using different terminology. And
ﬁnally, in 1928, the International Astronomical Union
decided to extirpate Argo and rename Canopus from Alpha
Argus to Alpha Carinae.
Ironically, Lacaille's Roman letters have been forgotten,
while the subdivisions that he introduced to make Roman
lettering feasible ended up cannibalizing their parent constellations. Things would probably have turned out very differently if he had used numbers rather than letters to denote
Argo's naked-eye stars.

¢ Contributing Editor TONY FLANDERS had his last complete
view of Greater Argo a few hours after watching a total solar
eclipse from Argentina on July 2, 2019.
FURTHER READING: My favorite resource for constellation
history is Ian Ridpath's superb book and website Star Tales
(ianridpath.com/startales/contents.htm).
sk yandtelescope.org * MARCH 2 02 0

http://www.ianridpath.com/startales/contents.htm http://www.skyandtelescope.org

Sky & Telescope - March 2020

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