What event, considered to be a birders principal meeting in South America, is held every orbital period of the Earth moving in its orbit around the sun?
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South American Bird Fair The South American Birdwatching Fair is an annual event for birdwatchers, held every year in a different country of the continent. It is described as the birder's principal meeting in South America, with people from all the world.
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Year A year is the orbital period of the Earth moving in its orbit around the Sun. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the globe, four seasons are generally recognized: "spring", "summer", "autumn" and "winter". In tropical and subtropical regions several geographical sectors do not present defined seasons; but in the seasonal tropics, the annual "wet" and "dry" seasons are recognized and tracked.
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Conjunction (astronomy) In astronomy, a conjunction occurs when two astronomical objects or spacecraft have either the same right ascension or the same ecliptic longitude, usually as observed from Earth.
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Shiva Hypothesis William Napier (astronomer) and Victor Clube in their 1979 Nature Magazine article, 'A Theory of Terrestrial Catstrophism' proposed the idea that gravitational disturbances caused by the Solar System crossing the plane of the Milky Way galaxy are enough to disturb comets in the Oort cloud surrounding the Solar System. This sends comets in towards the inner Solar System, which raises the chance of an impact. According to the hypothesis, this results in the Earth experiencing large impact events about every 30 million years (such as the Cretaceous–Paleogene extinction event).
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Equinox (disambiguation) An equinox in astronomy is the event when the Sun can be observed to be directly above the equator.
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Santa Rosa storm The Santa Rosa Storm occurs in the Southern Hemisphere up to five days earlier than or five days later than the festival of Santa Rosa of Lima, Perú, celebrated on August 30 each year.
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Orbital speed The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. It can be used to refer to either the mean orbital speed, i.e. the average speed as it completes an orbit, or the speed at a particular point in its orbit such as perihelia.
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Pass (spaceflight) A pass, in spaceflight and satellite communications, is the period in which a satellite or other spacecraft is above the local horizon and available for radio communication with a particular ground station, satellite receiver, or relay satellite (or, in some cases, for visual sighting). The beginning of a pass is termed "acquisition of signal"; the end of a pass is termed "loss of signal". The point at which a spacecraft comes closest to a ground observer is the "time of closest approach".
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South Pacific convergence zone The South Pacific Convergence Zone (SPCZ), a reverse-oriented monsoon trough, is a band of low-level convergence, cloudiness and precipitation extending from the Western Pacific Warm Pool at the maritime continent south-eastwards towards French Polynesia and as far as the Cook Islands (160W, 20S). The SPCZ is a portion of the Intertropical Convergence Zone (ITCZ) which lies in a band extending east-west near the Equator but can be more extratropical in nature, especially east of the International Date Line. It is considered the largest and most important piece of the ITCZ, and has the least dependence upon heating from a nearby landmass during the summer than any other portion of the monsoon trough. The SPCZ can affect the precipitation on Polynesian islands in the southwest Pacific Ocean, so it is important to understand how the SPCZ behaves with large-scale, global climate phenomenon, such as the ITCZ, El Niño–Southern Oscillation, and the Interdecadal Pacific oscillation (IPO), a portion of the Pacific decadal oscillation.
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Celestial pole The north and south celestial poles are the two imaginary points in the sky where the Earth's axis of rotation, indefinitely extended, intersects the celestial sphere. The north and south celestial poles appear permanently directly overhead to an observer at the Earth's North Pole and South Pole, respectively. As the Earth spins on its axis, the two celestial poles remain fixed in the sky, and all other points appear to rotate around them, completing one circuit per day (strictly, per sidereal day).
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Round (Theosophy) A round, in the esoteric cosmology of Theosophy, Anthroposophy and Rosicrucianism, is a cosmic cycle or sequence by which an evolving reincarnating being passes through the various stages of existence as the Earth, the Solar System or the Cosmos comes into and passes out of manifestation.
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Meridian circle The meridian circle is an instrument for timing of the passage of stars across the local meridian, an event known as a culmination, while at the same time measuring their angular distance from the nadir. These are special purpose telescopes mounted so as to allow pointing only in the meridian, the great circle through the north point of the horizon, the zenith, the south point of the horizon, and the nadir. Meridian telescopes rely on the rotation of the Earth to bring objects into their field of view and are mounted on a fixed, horizontal, east–west axis.
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International Halley Watch Halley's Comet, named after English astronomer Edmund Halley who first demonstrated its periodicity, returns to the vicinity of the Sun and Earth approximately every 76 years. Since comets are believed to be the most primordial objects in the solar system, their study is of great importance to planetary science. At the time of the 1986 return (technically, "apparition") of the comet, astronomical telescopes and related instrumentation were vastly more sensitive than for any previous apparition. Consequently, the International Halley Watch (IHW) was organized to stimulate, standardize, collect, and archive observations of the comet.
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Diurnal cycle A diurnal cycle is any pattern that recurs every 24 hours as a result of one full rotation of the Earth with respect to the Sun.
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Lunar Saros 153 Saros cycle series 153 for lunar eclipses occurs at the moon's descending node, repeats every 18 years 11 and 1/3 days. It contains 71 events, (48 listed before 3000).
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Earth's rotation Earth's rotation is the rotation of Planet Earth around its own axis. Earth rotates eastward, in prograde motion. As viewed from the north pole star Polaris, Earth turns counterclockwise.
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Ephemeris In astronomy and celestial navigation, an ephemeris (plural: ephemerides; from Latin "ephemeris", "diary", from Greek: εφημερίς , "ephēmeris ", "diary, journal") gives the positions of naturally occurring astronomical objects as well as artificial satellites in the sky at a given time or times. Historically, positions were given as printed tables of values, given at regular intervals of date and time. Modern ephemerides are often computed electronically from mathematical models of the motion of astronomical objects and the Earth. Even though the calculation of these tables was one of the first applications of mechanical computers, printed ephemerides are still produced, as they are useful when computational devices are not available.
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Osculating orbit In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space at a given moment in time is the gravitational Kepler orbit (i.e. ellipse or other conic) that it "would have" about its central body if perturbations were not present. That is, it is the orbit that coincides with the current orbital state vectors (position and velocity).
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September equinox The September equinox (or Southward equinox) is the moment when the Sun appears to cross the celestial equator, heading southward. Due to differences between the calendar year and the tropical year, the September equinox can occur at any time from the 21st to the 24th day of September.
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Solar eclipse of November 3, 1994 A total solar eclipse occurred on November 3, 1994. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon's apparent diameter is larger than the Sun's, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across Earth's surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. Totality was visible in Peru, northern Chile, Bolivia, northern Argentina, Paraguay including the northeastern part of its capital Asunción, Brazil and Gough Island of British overseas territory of Saint Helena, Ascension and Tristan da Cunha. The Iguazu Falls, one of the largest waterfalls systems in the world, also lies in the path of totality.
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Chunyun Chunyun (), also referred to as the Spring Festival travel season or the "Chunyun" period, is a period of travel in China with extremely high traffic load around the time of the Chinese New Year. The period usually begins 15 days before Lunar New Year's Day and lasts for around 40 days. The number of passenger journeys during the Chunyun period is projected to be hitting over 2.9 billion in 2016. It has been called the largest annual human migration in the world. Rail transport experiences the biggest challenge during the period, and myriad social problems have emerged. This phenomenon is also seen in some other East Asian countries such as Japan and South Korea.
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El Niño El Niño (] ) is the warm phase of the El Niño Southern Oscillation (commonly called ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (between approximately the International Date Line and 120°W), including off the Pacific coast of South America. El Niño Southern Oscillation refers to the cycle of warm and cold temperatures, as measured by sea surface temperature, SST, of the tropical central and eastern Pacific Ocean. El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific. The cool phase of ENSO is called "La Niña" with SST in the eastern Pacific below average and air pressures high in the eastern and low in western Pacific. The ENSO cycle, both El Niño and La Niña, cause global changes of both temperatures and rainfall.