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historical observation venus
Venus is the most well-known
astronomical feature in Earth's morning and evening
sky (other than the Sun and Moon), and has been
known from the past. One of the oldest surviving
astronomical documents, from the Babylonian library
of Ashurbanipal around 1600 BC, is a 21-year record
of the appearances of Venus (which the early Babylonians
called Nindaranna). The ancient Sumerians and
Babylonians called Venus Dil-bat or Dil-i-pat;
in Akkadia it was the special star of the mother-god
Ishtar; and in Chinese it is Jin-xing (??), the
planet of the metal element.
In India, Venus is called Shukra Graha (the planet
Shukra) which is named after a powerful saint
Shukra. The word 'Shukra' also associated with
semen, or generation.Venus as a brilliant "Evening
Star" next to crescent moon.Venus was considered
as the most important celestial body observed
by the Maya, who called it Chak ek, "the
Great Star", possibly more important even
than the Sun.
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The Mayans monitored the
activities of Venus intimately and observed
it in daytime. The positions of Venus and
other planets were thought to influence
life on Earth, so Maya and other ancient
Mesoamerican cultures timed wars and other
important events based on their observations.
In the Dresden Codex, the Maya included
an manual showing Venus's full cycle, in
five sets of 584 days each (approximately
eight years), after which the patterns repeated
(since Venus has a synodic period of 583.92
days). |
At the half-full phase Venus
is at greatest elongation — east of the
Sun when an evening star and west of the Sun as
a morning star. The precise angle the planet makes
with the Sun at this point in time varies approximately
from 45.0° to 47.8° depending on whether
Earth and Venus are at perihelion or aphelion.
This range is much lesser than that of Mercury
because Venus's orbit is far less eccentric than
Mercury's.
Early Greeks thought that the evening and morning
appearances of Venus represented two disparate
objects, calling it Hesperus when it appeared
in the western evening sky and Phosphorus when
it appeared in the eastern morning sky. They finally
came to distinguish that both objects were the
same planet; Pythagoras is given glory for this
insight. In the 4th century BC, Heraclides Ponticus
proposed that both Venus and Mercury orbited the
Sun rather than Earth.
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