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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] OFFTOPIC: the dangers of shortsightedness
Warning: only philosophically on topic, no ObXML content inside.
The naming of stars is a difficult matter, not one of your everyday
holiday games. The sky is divided into 88 arbitrary areas of varying
size called constellations, and ordinary stars are named in order of
brightness by a Greek letter followed by the name of the constellation
(in Latin, traditionally in the genitive case). Thus Alpha Centauri is
the brightest star in the constellation of the Centaur, and Tau Ceti is
the 19th brightest star in the constellation of the Whale.
From the 25th brightest star on, numbers are used. This system is fairly
simple and rational, since stars are naturally going to be discovered
in order from brightest to dimmest, as telescopes become more powerful.
Stars which are, for any reason, of variable brightness don't fit neatly
into the rank order. If the star already had an ordinary name before
its variability was noticed, it keeps it. Otherwise, variable stars are
given Latin-letter names in order of discovery, followed again by the
name of the constellation, thus: R, S, T, U, V, W, X, Y, Z. S Doradus,
for example, one of the most luminous (and bizarre) stars known, is the
second variable star discovered in the constellation of the Dolphin.
(The reason for beginning with R seems to be forgotten.) All was well.
But some constellations were found to contain more than nine variable
stars.
No problem: astronomers went to two Latin letters for the 10th star
onwards, thus: RR, RS, ... RZ, SR, SS, ..., SZ, TR, ... ZZ. All was
well.
But some constellations were found to contain more than 90 variable stars.
No problem: astronomers wrapped around the Latin alphabet, thus:
AA, AB, ... AZ, ..., BA, ... QZ, omitting the letter J (most of this
system was invented in Germany, which was still on Fraktur at the time).
All was well.
But some constellations were found to contain more than 334 variable
stars.
Two-letter sequences beginning with R-Z had already been been used at
an earlier stage, so RA, ... RQ, SA, ..., SQ, ... ZQ were rejected.
Instead the final stage of nomenclature became (at very long last)
V335, V336, .... Which could and should have been done in the first
place instead of the fourth place.
Caveat nomenclator.
--
John Cowan <jcowan@r...>
http://www.reutershealth.com http://www.ccil.org/~cowan
Yakka foob mog. Grug pubbawup zink wattoom gazork. Chumble spuzz.
-- Calvin, giving Newton's First Law "in his own words"
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