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Dorado was introduced by Johann Bayer in 1603 in his epoch-making
star atlas, Uranometria.
Dorado, "The Goldfish", is also known as "The
Swordfish". While the Bayer stars are not
very bright, there are several objects of interest in the constellation,
notably the Large Magellanic Cloud and the Tarantula Nebula.
Double stars:
While Dorado has its share of binaries, they are quite dim and not
particularly interesting. The one exception might be h3796.
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h3796 is a multiple group found in the vicinity of NGC 2070 (see
below for this deep sky object).
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The principal star is nine-magnitude while most of the other dozen or so
companions are in the 12-14 magnitude category.
AB: 9, 10; PA 213º, separation 0.5".
A full listing of the other companions' position angles and separations is given in Burnham (p.833).
Variable stars:
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Alpha Doradus is an alpha-CV type variable: 3.26-3.3 every 2d
23m.
Beta Doradus is a cepheid: 3.46-4.08 every 9d20m.
Gamma Doradus is an EW type variable: 4.23-4.27.
R Doradus is a semi-regular variable, 4.8 to 6.6 about every 338
days.
Deep Sky Objects:
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NGC 2070, the Tarantula Nebula, is a gaseous section of the
Large Magellanic Cloud. The nebula is so bright it goes by the name
30 Doradus. Dozens of supergiant stars are clustered at its
centre, furnishing the nebula's light. With a diameter of about a
thousand light years, if the Tarantula Nebula were moved to Orion - at
the same distance as the Orion Nebula - then it would entirely fill the
constellation of Orion.
The Large Magellanic Cloud is a miniature galaxy about 200,000
light years away, a satellite of the Milky Way. It has perhaps a tenth
of the mass of our own Milky Way Galaxy, with roughly 10,000 million
stars (or ten billion if you wish).
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A printed version of this web site ["The Constellations
Pocket Guide"] is available, covering all 88 constellations and their graphics.
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