Quando a Lua vem perdendo sua luminosidade
Com um abraço estrelado,
Messier 45Open Cluster M45 , type 'c', in Taurus
|Right Ascension||03 : 47.0 (h:m)|
|Declination||+24 : 07 (deg:m)|
|Visual Brightness||1.6 (mag)|
|Apparent Dimension||110.0 (arc min)|
Known pre-historically. Mentioned by Homer about 750 B.C., by biblical Amos about 750 B.C., and by Hesiod about 700 B.C.
The Pleiades, also known as Messier 45 (M45), are among those objects which are known since the earliest times. At least 6 member stars are visible to the naked eye, while under moderate conditions this number increases to 9, and under clear dark skies jumps up to more than a dozen (Vehrenberg, in his Atlas of Deep Sky Splendors, mentions that in 1579, well before the invention of the telescope, astronomer Moestlin has correctly drawn 11 Pleiades stars, while Kepler quotes observations of up to 14).
According to Kenneth Glyn Jones, the earliest known references to this cluster are mentionings by Homer in his Ilias (about 750 B.C.) and his Odyssey (about 720 B.C.), and by Hesiod, about 700 B.C.. According to Burnham, they were seen in connection to the agricultural seasons of that time. Also, and the Bible has three references to the Pleiades (the Hebrew "Kiymah"): Job 9:7-9, Job 38:31-33, and Amos 5:8; the prophet Amos is believed to have given his message in 750 B.C. or 749 B.C., while there is no consent on the dating of the book of Job: Some believe it was written about 1,000 B.C. (the regency of Kings David and Solomon in old Israel) or earlier (Moses, about 13th to 16th century B.C.), others give reasons that it may have been created as late as the 3rd to 5th century B.C.. The present author [hf] does not know if the cluster is mentioned in one of the earlier Assyrian or Sumerian sources.
The Pleiades also carry the name "Seven Sisters"; according to Greek mythology, seven daughters and their parents. Their Japanese name is "Subaru", which was taken to christen the car of same name. The Persian name is "Soraya", after which the former Iranian empress was named. Old European (e.g., English and German) names indicate they were once compared to a "Hen with Chicks". Other cultures tell more and other lore of this naked-eye star cluster. Ancient Greek astronomers Eudoxus of Knidos (c. 403-350 BC) and Aratos of Phainomena (c. 270 BC) listed them as an own constellation: The Clusterers. This is also referred to by Admiral Smyth in his Bedford Catalog.
Burnham points out that the name "Pleiades" may be derived from either the Greek word for "to sail", or the word "pleios" meaning "full" or "many". The present author prefers the view that the name may be derived from the mythological mother, Pleione, which is also the name of one of the brighter stars.
On March 4, 1769, Charles Messier included the Pleiades as No. 45 in his first list of nebulae and star clusters, published 1771
The Pleiades nebulae are blue-colored, which indicates that they are reflection nebulae, reflecting the light of the bright stars situated near (or within) them.
The cluster is a great object in binoculars and rich-field telescopes, showing more than 100 stars in a field about 1 1/5 degrees in diameter. In telescopes, it is frequently even too large to be seen in one lowest magnification field of view.
As the Pleiades are situated close to the ecliptic (4 degrees off), occultations of the cluster by the Moon occur quite frequently: .........................Also, planets come close to the Pleiades cluster (Venus, Mars, and Mercury even occasionally pass through) to give a conspicuous spectacle.
As mentioned in the description for the Orion Nebula M42, it is a bit unusual that Messier added the Pleiades (together with the Orion Nebula M42/M43 and the Praesepe cluster M44) to his catalog, and will perhaps stay subject to speculation.
LEIA MAIS, MUITO MAIS
em uma área de um grau de diâmetro
e facilmente visível a olho nu.
seis das quais podem ser vistas a olho nu e uma invisível ou “perdida”.
e foram levadas para o céu
para escaparem do Gigante Orion que as importunava.
para o texto explicativo acima acerca esta belíssima imagem
realizada por Babak Tafreshi)
e por isso escondeu-se
por ser a única filha que não foi casada com um deus.
em função de sua dor pela destruição de Ilium,
que foi fundada por seu filho Dardanos.
Astronomy Picture of the Day
|Autor||NASA, ESA, AURA/Caltech, Palomar Observatory|
The science team consists of: D. Soderblom and E. Nelan (STScI), F. Benedict and B. Arthur (U. Texas), and B. Jones (Lick Obs.)