http://www.skyandtelescope.com.au 39XSTILL GAZING A bust of Lacaille in his dress wig, above a carved
telescope and palms of honour, stands in a small park today in his home
HAVANG / WIKIMEDIA COMMONSvillage of Rumigny, Ardennes, France.
a plumb bob to deviate enough of a trace from vertical
to produce the odd result. Newton’s Law of Gravitation
predicted the effect, and historians have long debated why
Lacaille neglected it. Some say Lacaille, a Frenchman, may
have had an unconscious reluctance to apply the theory of
an English scientist. Others think it was just an oversight, an
easy one to make.
Before he left the Cape, Lacaille also measured Cape
Town’s longitude using Jupiter’s moons, kept tide and
weather records, and mapped the area. He collected shells,
plants, rocks and the skin of a wild donkey and shipped
them back to the King’s royal gardens in France. It’s small
wonder that Sir David Gill, the distinguished director of
the Cape Observatory from 1879 to 1907, said of Lacaille’s
time in South Africa, “This was one of the most remarkable,
successful, and useful scientific expeditions ever undertaken.”Return to France
Lacaille returned to France after a 10-month detour in
which he surveyed the islands now known as Mauritius and
Réunion in the Indian Ocean. In his journal he records his
indifference to these tropical paradises (he was “bored to
tears”) and his longing to return to France to continue his
work. He finally arrived in Paris on June 28, 1754, after an
absence of three years, eight months.
Lacaille was greeted in France as a scientific hero, a “star
returning above the horizon”. This was the long-lost Age of
Reason, when scientists were as celebrated as sports heroes
today. But the modest Lacaille would have none of it. He
refused the fanfare and trappings of fame, wishing only to
return to his quiet observatory at the Collège Mazarin.
Supported by a small pension from the Academy, Lacaille
resumed work. He produced and presented to the Academy
an engraved star map of the heavens south of the Tropic
of Capricorn, plotting naked-eye stars and his 14 odd new
constellations. Although not shown on this engraving,
Lacaille also split the enormous Argo Navis (the Ship of
the Argonauts) into three smaller constellations: Puppis,
the Stern or Poop; Vela, the Sails; and Carina, the ship’s
Body or Keel. A Latinised version of his planispheric map
was included in his Coelum Australe Stelliferum, published
posthumously. This map served as a basis for Jean Fortin’s
widely read 1776 Atlas Celeste.
In 1930, when the International Astronomical Union
settled on today’s canon of 88 constellations covering
every point on the celestial sphere, Lacaille’s collection of
machinery made the cut.
From 1756 through 1761, Lacaille precisely measured star
positions along the zodiac to provide better references points
for measuring positions of the planets and Moon. He edited
his textbooks, published his table of atmospheric refractive