Being part of the Southern
Cross, the jewel box can’t be missed when searching the area. This remarkable
and beautiful open cluster is located at just about 1 arc degree southeast from
Mimosa (β Cru).
The
sky was clear; the constellation was ±25° above the horizon. The full moon was
setting. Even in those good conditions, the only stars visible with the naked
eye in this region of the sky were α Cen and β Cen and the four forming the Southern
Cross (mostly stars of 1st and 2nd magnitude).
In
the 20mm erecting eyepiece, it appears as a bright group of stars forming a
triangle which reminds me of the Hyades shape.
The
image with the 10mm eyepiece is much more extraordinary: the six stars forming the triangle stand out,
appearing like a group of precious stones, just like Sir John Herschel described
them in the XIX century, deserving the name he gave them. Beside the right side
of the triangle’s base (in the image at 9-10 hours from the inverted triangle’s
center), there is a very fine group of stars, unresolved with the binoculars
that make the region seem to glow with a haze surrounded by some stars above 10
magnitude.
The
jewel box was first catalogued as a star with the Greek letter K (kappa) in the Bayer’s catalogue and
was posteriorly discovered as an apparently nebulous object consisting of many
stars by Nicolas Louis de Lacaille during 1751-1752. About 80 years later, it was
named by Sir John Hershel as the Jewel Box and even though
the whole
cluster is also known as the Kappa Crucis cluster, its second brightest star
(left side of the inverted triangle’s base in the sketch) received the
nomenclature of K Cru. Forming a
triangle with K Cru stars, there are HIP62918 supergiant red star and HIP62913,
which is a double star (HIP HIP62913 A and HIP62913 B). I saw this double star,
forming a obtuse triangle with HIP62918.
Enjoy
this marvelous creation of God!
Excelente logro artístico,e interesante nota histórica de su descubrimiento,saludos,César.
ReplyDeleteMuchas gracias por sus comentarios y por visitarme señor Cesar. Muchos saludos desde China.
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