|
|
||||||||||||||||||||||||||||||||||||||||
|
|
|
|||||||||||||||||||||||||||||||||||||||
![]() |
|
|||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||
![]() |
|
|||||||||||||||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||||||||||||||||
|
One of the constellations introduced by the
French astronomer Nicolas Louis de Lacaille following his
mapping of the southern skies in 1751–52. On his 1756
planisphere he called it l’Equerre et la Regle and
depicted it as a draughtsman’s set-square and rule,
placed next to the compasses (le Compas, now known as Circinus)
and the southern triangle (Triangulum Australe), an earlier
invention of Keyser and de Houtman which Lacaille visualized as
a builder’s level. On the 1763 edition of the planisphere
the name of the constellation was Latinized and shortened to
Norma, meaning set square, although others continued to call it
Norma et Regula, as did Bode on his atlas of 1801.
In his widely quoted book Star Names, Their Lore and Meaning, the historian R. H. Allen called this
constellation “the Level and Square”. Allen said
that the French edition of Flamsteed’s star atlas (i.e.
the Atlas Céleste of Jean Fortin) showed it as Niveau, the level,
but a glance at that atlas shows he is wrong. The alternative name
“level” was actually applied to the southern
triangle, Triangulum Australe. Allen seemingly misread the
French map and transferred the name to the wrong constellation,
in a reprise of the way in which star names were misapplied
through misreadings of maps down the ages. Allen’s error
has caused confusion ever since.
Norma, shown under the name Norma et Regula in the Uranographia of Johann Bode. “Rule and Square” is an old English pub name.
The brightest stars of Norma are of only
fourth magnitude and none have names. Because of changes in the
constellation’s boundaries since Lacaille’s time,
Norma no longer has stars labelled Alpha or Beta. The stars
that Lacaille designated Alpha and Beta Normae are now part of
Scorpius where they are known as N and H Scorpii respectively.
For a modern chart of this region, click here. Incidentally,
Norma shares this distinction with Puppis and Vela, both of
which lack stars labelled Alpha and Beta because they were once
part of the much larger constellation Argo Navis; when Argo was
split into three by Lacaille, the stars Alpha and Beta ended up
in the third subdivision, Carina.
© Ian Ridpath. All rights reserved
|
|
|||||||||||||||||||||||||||||||||||||||
|
|
|
|
|
|
|
|
|
| ||||||||||||||||||||||||||||||||