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1a. |
DUBHE, POLARIS
ALIOTH, SCHEDAR |
1b. |
ACHERNAR, ACRUX
CANOPUS, PEACOCK
RIGEL KENT. |
2. |
1 DAY LESS 10 MIN
1º PER DAY, 30º OR
1/12 OF 0 PER MONTH |
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3000 300 |
x 2 = 20 HOURS. |
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GHA. ALEMMA 52º... |
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What does this stuff mean? |
Curiously, the readable stuff on Steed's cuff isn't all just meaningless gobbledygook. Based on the
visible answers, we can infer that the corresponding questions have something to do with, of all things,
celestial navigation. Steed's cuff is shown at left, with the readable portion transcribed below it.
And now, here's what it all means:
1a. Dubhe is Ursae
Majoris, the brightest star in the Big Dipper. It's the star on the upper right of the
ladle. Polaris is Ursae
Minoris, the brightest star in the Little Dipper, the North Star. Alioth is
Ursae Majoris, the first star in the handle of the Big Dipper away from the ladle.
Schedar is Cassiopeiæ, the
brightest star in Cassiopeia. It's the bottom of the second "V" described in the "W" of the
constellation. All of these stars are relatively close together in the northern sky.
1b. Achernar is Eridani,
the brightest star in Eridanus the River; Acrux is
Crux, the brightest star of the Southern Cross; Canopus is
Carinæ, in the constellation Argo Navis, the ship of the Argonauts. "Carina" is the Keel of
the ship—the constellation was subdivided into three parts for convenience (the other two
parts are Puppis, the Stern, and Vela, the Sail). The Peacock is the English name for
the constellation Pavo. These stars are all southern stars and not visible from England.
Rigel refers to ß Orionis, Orion's left knee (on the lower right as we look at
him), but Rigil Kentaurus refers to our old friend Centauri. Both are navigational
stars. The Centaur, a southern constellation, is not visible from England, but in keeping
with the other stars, this may be the one to which Steed's cuff refers, especially since the
word "Kent" (presumably an abbreviation for "Kentaurus") appears after "Rigel"—but if so,
then "Rigil" is misspelled. So much for master minds. Alternatively, Kent is the name of a
southeastern county in England, but what that has to do with anything is anybody's guess.
2. The three dot symbol ()
is mathematical shorthand for "therefore" in a proof. Although the math itself is
straightforward, in the context of celestial navigation it makes little sense: a degree of
rotation of the Earth (i.e, as the stars move a degree westward) takes four minutes of time, so
ten minutes of time can't be equal to one celestial degree of east-west arc. Ten minutes of time
is equivalent to 2½ degrees of arc.
GHA stands for "Greenwich Hour Angle" and is the measurement in degrees, minutes, and
tenths of minutes of arc of a star's "longitude" at any given time west of the Greenwich
meridian (0 degrees longitude). It is used solely by navigators; astronomers use "right
ascension," which is the same thing, only east of the Greenwich meridian. Alemma has no
meaning, but "lemma" is a step in a mathematical proof, and "analemma" is the figure 8 described
by the position of the sun at sunrise during a calendar year, which is often seen on the sides
of globes.
"" stands for Aries, but
in astronomy and celestial navigation, it refers to the point in the sky where the sun
crosses the equator on the Vernal Equinox, called the "first point of Aries" (so-called
because when the Babylonians first started to chart it, it occurred in that constellation,
even though it has moved considerably since then due to the precession of the Equinox). It
is used to compute the GHA of a star. The GHA of the first point of Aries is listed in the
Nautical Almanac for every minute of the year. By adding the SHA (Sidereal Hour Angle) of a
star (its angular distance westward from Aries) to Aries' GHA, you get the star's GHA. It
also corresponds to the waist of the figure 8 of the solar analemma. However, the symbol
could also be a lower case gamma ().
—James Warren |