Perseids

Information about Perseids

The Perseids (pÃ»r'sē-ĭdz, or ['pʰɝsijɪdz] in IPA) are a prolific meteor shower^[1] associated with the comet Swift-Tuttle. The Perseids are so called because the point they appear to come from, called the radiant, lies in the constellation Perseus. Meteor showers occur when Earth moves through a meteor stream. The stream in this case is called the Perseid cloud and it stretches along the orbit of the Comet Swift-Tuttle. The cloud consists of particles ejected by the comet as it passed by the Sun. Most of the dust in the cloud today is approximately a thousand years old. However, there is also a relatively young filament of dust in the stream that boiled off the comet in 1862. The approximate rate of meteors originating from this filament is much higher than normal.

A Perseid (possibly 2) and Milky way

Observation

The famous Perseid meteor shower has been observed for about 2000 years, with the first known information on these meteors coming from the Far East. In early Europe, the Perseids came to be known as the "tears of St. Lawrence."

The shower is visible from mid-July each year, with the greatest activity between August 8 and 14, peaking about August 12. During the peak, the rate of meteors reaches 60 or more per hour. They can be seen all across the sky, but because of the path of Swift-Tuttle's orbit, Perseids are mostly visible in the northern hemisphere.

To experience the shower in its full, one should observe in the dark of a clear moonless night, from a point far outside any large cities, where stars are not dimmed by light pollution. The Perseids have a broad peak, so the shower is visible for several nights. On any given night, activity starts slowly in the evening but picks up by 11 p.m., when the radiant gets reasonably high in the sky. The meteor rate increases steadily through the night as the radiant rises higher, peaking just before the sky starts to get light, roughly 1Â½ to 2 hours before sunrise.

2007

The Perseid meteor shower peaks on the new-Moon night of Sunday–Monday, August 12–August 13 and can be seen from any place in the northern hemisphere. The Perseid meteors appear to stream away from their radiant near the border of Perseus and Cassiopeia.

The meteor rate, for an observer at a dark-sky site in the northern temperate latitudes, increases to roughly 30 per hour in the predawn hours on Saturday, 45 per hour on Sunday morning, and 80 per hour before the sky starts to get light on Monday morning.

Notes

1. ^ In Greek mythology, the Perseids, who claimed Perseus for progenitor, were a dynasty at Argos.

METEOR (Metric for Evaluation of Translation with Explicit ORdering) is a metric for the evaluation of machine translation output. The metric is based on the harmonic mean of unigram precision and recall, with recall weighted higher than precision.
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A meteor shower, some of which are known as a "meteor storm" or "meteor outburst", is a celestial event where a group of meteors are observed to radiate from one point in the sky. These meteors are small fragments of cosmic debris entering Earth's atmosphere at extremely high speed.
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comet is a small body in the solar system that orbits the Sun and (at least occasionally) exhibits a coma (or atmosphere) and/or a tail — both primarily from the effects of solar radiation upon the comet's nucleus, which itself is a minor body composed of rock, dust, and
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109P/Swift-Tuttle
Discovery
Discovered by: Lewis Swift
Horace Parnell Tuttle
Discovery date: July 16, 1862
Alternate designations: 1737 N1; 1737 II; 1862 O1;
1862 III; 1992 S2; 1992 XXVIII
Orbital characteristics ^A
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The radiant or apparent radiant of a meteor shower is the point in the sky that (to a planetary observer) meteors appear to originate from. The Perseids, for example, are meteors which appear to come from a point within the constellation of Perseus.
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constellation of Orion is the area outlined in the dashed yellow line. Orion contains a striking and well-known star pattern that has the form of a hunter.]] A constellation is any one of the 88 areas into which the sky — or the celestial sphere — is divided.
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Perseus

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List of stars in Perseus
Abbreviation: Per
Genitive: Persei
Symbology: Perseus
Right ascension: 3 h
Declination: +45
Area: 615 sq. deg.
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EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001. Their greatest hit, their debut single "time after time", peaked at #13 in the Oricon singles chart.
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The Sun

Observation data
Mean distance
from Earth 1.49610¹¹ m
(8.31 min at light speed)
Visual brightness (V) −26.74^m ^[1]
Absolute magnitude 4.
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Saint Lawrence (c. 225 – 258) (Latin: Laurentius - "laurelled") was one of the seven deacons of ancient Rome who were martyred under the persecution of Roman Emperor Valerian in the year 258.

History

St.
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LÃªre).

1806 - Santiago de Liniers re-takes the city of Buenos Aires after the first British invasion.

1833 - Chicago was founded.

1851 - Isaac Singer granted a patent for his sewing machine.

1877 - Asaph Hall discovers Deimos.
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Northern Hemisphere or northern hemisphere^[1] is the half of a planet that is north of the equator—the word hemisphere literally means 'half ball'. It is also that half of the celestial sphere north of the celestial equator.
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Light pollution is excess or obtrusive light created by humans. Among other effects, it disrupts ecosystems, can cause adverse health effects, obscures the stars for city dwellers, interferes with astronomical observatories, and wastes energy.
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LÃªre).

1806 - Santiago de Liniers re-takes the city of Buenos Aires after the first British invasion.

1833 - Chicago was founded.

1851 - Isaac Singer granted a patent for his sewing machine.

1877 - Asaph Hall discovers Deimos.
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August 13 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.

Events

3114 BC - According to the Lounsbury correlation, the Maya calendar starts.

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Cassiopeia

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List of stars in Cassiopeia
Abbreviation: Cas
Genitive: Cassiopeiae
Symbology: the Seated Queen
Right ascension: 1 h
Declination: +60
Area: 598 sq. deg.
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Table of meteor showers

Name Dates Peak dates ZHR Rating
Quadrantids Jan 1-Jan 5 Jan 3 15:20 +49 41 120 Strong
Gamma Velids Jan 1-Jan 15 Jan 5 08:20 -47 35 2 Weak
Alpha Crucids Jan 6-Jan 28 Jan 15 12:48 -63 50 3 Weak
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Greek mythology is the body of stories belonging to the Ancient Greeks concerning their gods and heroes, the nature of the world and the origins and significance of their own cult and ritual practices.
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Perseus, Perseos, or Perseas (Greek: Περσεύς, Περσέως, Περσέας
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