Observation Of Venus

Credit: NASA/JPL-Caltech - https://photojournal.jpl.nasa.gov/figures/PIA23791_fig2.jpg

As one of the brightest objects in the sky, Venus has been a major fixture in human culture for as long as records have existed. It has been made sacred to gods of many cultures, and has been a prime inspiration for writers and poets as the morning star and evening star. Venus was the first planet to have its motions plotted across the sky, as early as the second millennium BC.

To the naked eye, Venus appears as a white point of light brighter than any other planet or star, other than the Sun.

It is possible to view Venus in the midday sky because it is so bright; moreover, when the Sun is low on the horizon, Venus is easily visible. It is important to note that as an inferior planet, it always lies within about 47° of the Sun.

Viewing Venus from Pacific Northwest can be done either right before sunrise or before sunset. The planet is really visible in the sky in the West in the evening or rise before the Sun in the East. “Although any telescope (or steadily-held binoculars) will allow the phases of Venus to be seen, the planet is a notoriously difficult one to observe, for three main reasons. Firstly, whenever the planet is visible (shortly before sunrise or after sunset) it is positioned at a low altitude (angle above the horizon) where it is immersed in haze and atmospheric turbulence, which adversely affects the quality of the image seen in the telescope. Consequently most telescopic observers prefer to view the planet in full daylight – when its altitude is much higher – taking special care to shield the Sun from view. Secondly, the planet’s brilliance – although making it a very obvious and beautiful object to the naked-eye – causes a menacing glare when seen through a telescope. Thirdly, the planet itself is permanently cloaked in thick cloud, so its surface features are never visible through telescopes. Most amateur astronomers can therefore only expect to observe its characteristic phase changes, but little else.” [1]

As one of the brightest objects in the sky, Venus has been known since prehistoric times, and as such, many ancient cultures recorded observations of the planet. A cylinder seal from the Jemdet Nasr period indicates that the ancient Sumerians already knew that the morning and evening stars were the same celestial object. The Sumerians named the planet after the goddess Inanna, who was known as Ishtar by the later Akkadians and Babylonians.[2] She had a dual role as a goddess of both love and war, thereby representing a deity that presided over birth and death.[3] 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.

Because the movements of Venus appear to be discontinuous (it disappears due to its proximity to the sun, for many days at a time, and then reappears on the other horizon), some cultures did not immediately recognize Venus as single entity; instead, they assumed it to be two separate stars on each horizon: the morning star and the evening star. The Ancient Egyptians, for example, believed Venus to be two separate bodies and knew the morning star as Tioumoutiri and the evening star as Ouaiti.[4] The Ancient Greeks called the morning star Φωσφόρος, Phosphoros, the “Bringer of Light” or Ἐωσφόρος, Eosphoros, the “Bringer of Dawn”. The evening star they called Hesperos, otherwise known as Ἓσπερος, the “star of the evening” [5]. By Hellenistic times, the ancient Greeks identified it as a single planet, [6] which they named after their goddess of love, Aphrodite (Αφροδίτη) (Phoenician Astarte),[7] a planetary name that is retained in modern Greek. Hesperos would be translated into Latin as Vesper and Phosphoros as Lucifer (“Light Bearer”).

Venus was considered the most important celestial body observed by the Maya, who called it Chac ek,[8] or Noh Ek’, “the Great Star”. The Maya monitored the movements of Venus closely and observed it in daytime. The positions of Venus and other planets were thought to influence life on Earth, so the Maya and other ancient Mesoamerican cultures timed wars and other important events based on their observations. In the Dresden Codex, the Maya included an almanac showing Venus’s full cycle, in five sets of 584 days each, after which the patterns repeated.[9] The Maya civilization developed a religious calendar, based in part upon the motions of the planet, and held the motions of Venus to determine the propitious time for events such as war. They also named it Xux Ek‘, the Wasp Star. The Maya were aware of the planet’s synodic period, and could compute it to within a hundredth part of a day.[10]

Sources And Further Reading

Check out the Planetary Bodies Category for previous and upcoming articles on the solar system planets.

[1] = http://www.nakedeyeplanets.com/venus-telescope.htm
[2] = Cooley, Jeffrey L. (2008). “Inana and Šukaletuda: A Sumerian Astral Myth”KASKAL5: 161–172. ISSN 1971-8608.
[3] = Meador, Betty De Shong (2000). Inanna, Lady of Largest Heart: Poems of the Sumerian High Priestess Enheduanna. University of Texas Press. p. 15. ISBN 978-0-292-75242-9.
[4] = Cattermole, Peter John; Moore, Patrick (1997). Atlas of Venus. Cambridge University Press. p. 9. ISBN 978-0-521-49652-0.
[5] = “Definition of Hesperus”. www.thefreedictionary.com.
[6] = Fox, William Sherwood (1916). The Mythology of All Races: Greek and Roman. Marshall Jones Company. p. 247. ISBN 978-0-8154-0073-8. Retrieved 2009-05-16.
[7] = Greene, Ellen (1999). Reading Sappho: contemporary approaches. University of California Press. p. 54. ISBN 978-0-520-20601-4.
[8] = The Book of Chumayel: The Counsel Book of the Yucatec Maya, 1539-1638. Richard Luxton. 1899. pp. 6, 194. ISBN 9780894122446.
[9] = Milbrath, Susan (1999). Star Gods of The Mayans : Astronomy in Art, Folklore, and Calendars. Austin, TX: University of Texas Press. pp. 200–204, 383. ISBN 978-0-292-79793-2.
[10] = Sharer, Robert J.; Traxler, Loa P. (2005). The Ancient Maya. Stanford University Press. ISBN 978-0-8047-4817-9.

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