|
Lyrids
The April Lyrids are a meteor shower lasting from about April 15 to April 29 each year. The Radiant (meteor shower), radiant of the meteor shower is located near the constellations Lyra and Hercules (constellation), Hercules, near the bright star Vega. The peak of the shower is typically around April 22–23 each year. The source of the meteor shower are particles of dust shed by the Long period comet, long-period Comet C/1861 G1 Thatcher. The April Lyrids are the strongest annual shower of meteors from debris of a long-period comet, mainly because as far as other intermediate long-period comets go (200–10,000 years), this one has a relatively short orbital period of about 415 years. The Lyrids have been observed and reported since 687 BC; no other modern shower has been recorded as far back in time. The shower usually peaks around April 22 and the morning of April 23. Counts typically range from 5 to 20 meteors per hour, averaging around 10. As a result of light pollution, ob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C/1861 G1 (Thatcher)
Comet C/1861 G1 (Thatcher) is a long-period comet with roughly a 422-year orbit that is expected to return around 2283. It was discovered by A. E. Thatcher. It is responsible for the April Lyrid meteor shower. Carl Wilhelm Baeker also independently found this comet. The comet passed about from the Earth on 5 May 1861 and last came to perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ... (closest approach to the Sun) on 3 June 1861. C/1861 G1 is listed as a long-period "non-periodic comet" because it has not yet been observed at two perihelion passages. When it is seen to come back around 2283, it should receive the P/ designation. The comet is the parent body of the April Lyrids meteor shower. See also * C/1861 J1 – Great comet of 1861 * 153P/Ikeya–Zhang – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lyra
, from ; pronounced: ) is a small constellation. It is one of the 48 listed by the 2nd century astronomer Ptolemy, and is one of the modern 88 constellations recognized by the International Astronomical Union. Lyra was often represented on star maps as a vulture or an eagle carrying a lyre, and hence is sometimes referred to as Vultur Cadens or Aquila Cadens ("Falling Vulture" or "Falling Eagle"), respectively. Beginning at the north, Lyra is bordered by Draco, Hercules, Vulpecula, and Cygnus. Lyra is nearly overhead in temperate northern latitudes shortly after midnight at the start of summer. From the equator to about the 40th parallel south it is visible low in the northern sky during the same (thus winter) months. Vega, Lyra's brightest star, is one of the brightest stars in the night sky, and forms a corner of the famed Summer Triangle asterism. Beta Lyrae is the prototype of a class of binary stars known as Beta Lyrae variables. These binary stars are so close to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C/1861 G1
Comet C/1861 G1 (Thatcher) is a long-period comet with roughly a 422-year orbit that is expected to return around 2283. It was discovered by A. E. Thatcher. It is responsible for the April Lyrid meteor shower. Carl Wilhelm Baeker also independently found this comet. The comet passed about from the Earth on 5 May 1861 and last came to perihelion (closest approach to the Sun) on 3 June 1861. C/1861 G1 is listed as a long-period "non-periodic comet" because it has not yet been observed at two perihelion passages. When it is seen to come back around 2283, it should receive the P/ designation. The comet is the parent body of the April Lyrids meteor shower. See also * C/1861 J1 The Great Comet of 1861, formally designated C/1861 J1 and 1861 II, is a long-period comet that was visible to the naked eye for approximately 3 months. It was categorized as a great comet—one of the eight greatest comets of the 19th century ... – Great comet of 1861 * 153P/Ikeya–Zhang – pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteor Shower
A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so almost all of them disintegrate and never hit the Earth's surface. Very intense or unusual meteor showers are known as meteor outbursts and meteor storms, which produce at least 1,000 meteors an hour, most notably from the Leonids. The Meteor Data Centre lists over 900 suspected meteor showers of which about 100 are well established. Several organizations point to viewing opportunities on the Internet. NASA maintains a daily map of active meteor showers. Historical developments A meteor shower in August 1583 was recorded in the Timbuktu manuscripts.Abraham, Curtis"Stars of the Sahara" ''New Scientist'', issue 2617,15 August 2007, page 39–41 I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Longitude
Solar longitude, commonly abbreviated as Ls (pronounced ''ell sub ess''), is the longitude of the Sun as seen from a given body, i.e. the position of the Sun on the celestial sphere along the orbital plane of that body. It is also an effective measure of the position of the Earth (or any other Sun-orbiting body) in its orbit around the Sun, usually taken as zero at the moment of the vernal equinox. Since it is based on how far the Earth has moved in its orbit since the equinox, it is a measure of what time of the tropical year (the year of seasons) the planet is in, but without the inaccuracies of a calendar date, which is perturbed by leap years and calendar imperfections. Its independence from a calendar also allows it to be used to tell the time of year on other planets, such as Mars. Solar longitude does not increase linearly with time, the deviation being larger the greater the eccentricity of the orbit. For instance, here are the dates for multiples of 90° solar longitude on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zuo Zhuan
The ''Zuo Zhuan'' ( zh, t=左傳, w=Tso Chuan; ), often translated as ''The Zuo Tradition'' or as ''The Commentary of Zuo'', is an ancient Chinese narrative history traditionally regarded as a commentary on the ancient Chinese chronicle the '' Spring and Autumn Annals''. It comprises 30 chapters covering the period from 722 to 468BC, and focuses mainly on political, diplomatic, and military affairs from that era. For many centuries, the ''Zuo Zhuan'' was the primary text through which educated Chinese learned their ancient history. The ''Zuo Zhuan'' does not simply explain the wording of the ''Spring and Autumn Annals'', but rather expounds upon its historical background with rich and lively accounts of the history and culture of the Spring and Autumn period (771476 BC). The ''Zuo Zhuan'' is the source of more Chinese sayings and idioms than any other classical work, and its concise, flowing style served as a paragon of elegant Classical Chinese. Its tendency toward thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Meteor Organization
The International Meteor Organization (IMO) was formally founded in 1988 from predecessor gatherings over many years. IMO has several hundred members and was created in response to an ever-growing need for international cooperation on amateur and professional meteor work. The collection of meteor observations by several methods from all around the world ensures the comprehensive study of meteor showers and their relation to comets and interplanetary dust. IMO publishes a bimonthly journal called ''WGN''WGN = "werkgroepnieuws" (Dutch language), in English as "workgroup news". WGN was initially a circular before it became a journal. and holds an annual International Meteor Conference (IMC) in September.IMO website. See also *American Meteor Society The American Meteor Society, Ltd. (AMS) is a non-profit scientific organization established to encourage and support the research activities of both amateur and professional astronomers who are interested in the field of meteor astrono ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Meteor Society
The American Meteor Society, Ltd. (AMS) is a non-profit scientific organization established to encourage and support the research activities of both amateur and professional astronomers who are interested in the field of meteor astronomy. Its affiliates observe, monitor, collect data on, study, and report on meteors, meteor showers, meteoric fireballs, and related meteoric phenomena. The society publishes observations and scientific interpretations quarterly in '' Meteor Trails, The Journal of American Meteor Society''. Once per year they give the '' American Meteor Society Award'' to a person who has contributed to research on meteors. They also provide an annual research grant to a student of SUNY-Geneseo who has contributed to meteor research or to the AMS. History The society was founded in 1911 by Charles P. Olivier of the Leander McCormick Observatory. The initial enrollment was fifteen members. These were recruited by Olivier by letter. The first paper based on the obs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Washington Post
''The Washington Post'', locally known as ''The'' ''Post'' and, informally, ''WaPo'' or ''WP'', is an American daily newspaper published in Washington, D.C., the national capital. It is the most widely circulated newspaper in the Washington metropolitan area and has a national audience. As of 2023, the ''Post'' had 130,000 print subscribers and 2.5 million digital subscribers, both of which were the List of newspapers in the United States, third-largest among U.S. newspapers after ''The New York Times'' and ''The Wall Street Journal''. The ''Post'' was founded in 1877. In its early years, it went through several owners and struggled both financially and editorially. In 1933, financier Eugene Meyer (financier), Eugene Meyer purchased it out of bankruptcy and revived its health and reputation; this work was continued by his successors Katharine Graham, Katharine and Phil Graham, Meyer's daughter and son-in-law, respectively, who bought out several rival publications. The ''Post ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zenithal Hourly Rate
In astronomy, the zenithal hourly rate (ZHR) of a meteor shower is the number of meteors a single observer would see in an hour of peak activity if the radiant was at the zenith, assuming the seeing conditions are perfect (when and where stars with apparent magnitudes up to 6.5 are visible to the naked eye). The rate that can effectively be seen is nearly always lower and decreases the closer the radiant is to the horizon. Calculation The formula to calculate the ZHR is: ZHR = \cfrac where \overline = \cfrac represents the hourly rate of the observer. N is the number of meteors observed, and Teff is the effective observation time of the observer. Example: If the observer detected 12 meteors in 15 minutes, their hourly rate was 48 (12 divided by 0.25 hours). F = \cfrac This represents the field of view The field of view (FOV) is the angle, angular extent of the observable world that is visual perception, seen at any given moment. In the case of optical instrume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
