AMNH: Scientists Recover Nova First Spotted 600 Years Ago

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AMNH: Scientists Recover Nova First Spotted 600 Years Ago

Post by bystander » Thu Aug 31, 2017 5:48 pm

Scientists Recover Nova First Spotted 600 Years Ago by Korean Astrologers
American Museum of Natural History | 2017 Aug 30

On a cold March night in Seoul almost 600 years ago, Korean astrologers spotted a bright new star in the tail of the constellation Scorpius. It was seen for just 14 days before fading from view. From these ancient records, modern astronomers determined that what the Royal Imperial Astrologers saw was a nova explosion, but they had been unable to find the binary star system that caused it—until now. A new study published today by the journal Nature pinpoints the location of the old nova, which now undergoes smaller-scale “dwarf nova” eruptions. The work supports that idea that novae go through a very long-term life cycle after erupting, fading to obscurity for thousands of years, and then building back up to become full-fledged novae once more.

“This is the first nova that’s ever been recovered with certainty based on the Chinese, Korean, and Japanese records of almost 2,500 years,” said the study’s lead author Michael Shara, a curator in the American Museum of Natural History’s Department of Astrophysics.

A nova is a colossal hydrogen bomb produced in a binary system where a star like our Sun is being cannibalized by a white dwarf—a dead star. It takes about 100,000 years for the white dwarf to build up a critical layer of hydrogen that it steals from the sun-like star, and when it does, it blows the envelope off, producing a burst of light that makes the star up to 300,000 times brighter than the sun for anywhere from a few days to a few months.

For years, Shara has tried to pinpoint the location of the binary star that produced the nova eruption in 1437, along with Durham University’s Richard Stephenson, a historian of ancient Asian astronomical records, and Liverpool John Moores University astrophysicist Mike Bode. Recently, they expanded the search field and found the ejected shell of the classical nova. They confirmed the finding with another kind of historical record: a photographic plate from 1923 taken at the Harvard Observatory station in Peru and now available online as part of the Digitizing a Sky Century at Harvard (DASCH) project. ...

Proper-motion age dating of the progeny of Nova Scorpii AD 1437 - M. M. Shara et al Nova Scorpius 1437 A.D. is now a dwarf nova, age-dated by its proper motion - M. M. Shara et al
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Malmö Motto: Mångfald, Möten, Möjligheter

Post by neufer » Fri Sep 01, 2017 6:23 pm wrote:

April 23, 1437: Malmö in Denmark (now Sweden) receives its current coat of arms.

:arrow: Malmö Motto: Mångfald, Möten, Möjligheter
(Eng.: Diversity, Meetings, Possibilities) wrote:
<<Zīj-i Sultānī (Persian: زیجِ سلطانی‎‎) is a Zij astronomical table and star catalogue that was published in 1438-1439 by Ulugh Beg (الغ‌ بیگ) (March 22, 1394 in Sultaniyeh, Persia – October 27, 1449 Samarkand). It was the joint product of the work of a group of Muslim astronomers working under the patronage of Ulugh Beg at Samarkand's Ulugh Beg Observatory.

The Zij-i-Sultani is generally considered the most accurate and extensive star catalogue up to its time, surpassing its predecessors, including Ptolemy's work, Abd al-Rahman al-Sufi's Book of Fixed Stars, and the Maragheh observatory's Zij-i Ilkhani. It was not surpassed until the work of Taqi al-Din and Tycho Brahe in the 16th century.

The serious errors which Ulugh Beg found in previous Zij star catalogues induced him to redetermine the positions of 992 fixed stars, to which he added 27 stars from al-Sufi's Book of Fixed Stars (964), which were too far south for observation from Samarkand. This catalogue, one of the most original of the Middle Ages, was edited by Thomas Hyde at Oxford in 1665 under the title Tabulae longitudinis et latitudinis stellarum fixarum ex observatione Ulugbeighi, by G. Sharpe in 1767, and in 1843 by Francis 'Baily's beads' Baily in vol. xiii. of the Memoirs of the Royal Astronomical Society.

In 1437, Ulugh Beg determined the length of the sidereal year as 365d 6h 10m 8s (an error +58s). In his measurements over many years he used a 50 m high gnomon. This value was improved by 28s, 88 years later in 1525 by Nicolaus Copernicus (1473-1543), who appealed to the estimation of Thabit ibn Qurra (826-901), which was accurate to +2s. However, Ulugh Beg later measured another more precise value as 365d 5h 49m 15s, which has an error of +25s, making it more accurate than Copernicus' estimate which had an error of +30s. Ulugh Beg also determined the Earth's axial tilt as 23.5047 degrees.>> wrote: <<The Ulugh Beg Observatory is an observatory in Samarkand, Uzbekistan. Built in the 1420s by the Timurid astronomer Ulugh Beg, it is considered by scholars to have been one of the finest observatories in the Islamic world. Some of the famous Islamic astronomers who worked at the observatory include Al-Kashi, Ali Qushji, and Ulugh Beg himself. The observatory was destroyed in 1449 and rediscovered in 1908.

While working at the excavation site, Vyatkin found one of the most important astronomical instruments used at the observatory: a large arch that had been used to determine midday. A trench of about 2 metres wide was dug in a hill along the line of the Meridian and in it was placed the arc of the instrument. Today, there is a circular base showing the outline of the original structure and the doorway leads to the remaining underground section of the Fakhrī sextant that is now roofed over. The sextant was 11 metres long and once rose to the top of the surrounding 3 storey structure although it was kept underground to protect it from earthquakes. Calibrated along its length, it was the world's largest 90 degree quadrant at the time, with a radius of 40.4 metres. The radius of the meridian arc was according to a trusted middle age Turkish astronomer approximately 50 metres and was said to be the same height as the dome of the Hagia Sofia mosque in Istanbul. It was used for the observation of the Sun, Moon and other celestial bodies, and along with other sophisticated equipment such as an armillary and an astrolabe, the astronomers working in Samarkand could determine noon every day according to the meridional height of the Sun, distance from the zenith and declination.>>
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Re: AMNH: Scientists Recover Nova First Spotted 600 Years Ago

Post by Ann » Fri Sep 01, 2017 7:20 pm

I feel I should comment... It was very interesting to read about Ulugh Beg, the man with the tremendous gnomon and wonderfully accurate observations of the Sun, the stars and the Earth itself (its axial tilt and the length of its year). And to think that Malmö, my city, got its coat of arms during his lifetime.
Malmö in 1588.
Back then it was often called Elbogen.
The Elbow of Mamö (right) and the hippopotamus of Copenhagen (left).
The Bridge of Öresund stretches between them, reaching the man-made
island of Pepparholm and diving below Öresund as it turns into a tunnel.
Öresundsbron, 10 april 2004.

But Malmö itself is older than Ulugh Beg. There is a letter from 1275 granting the tradesmen of Malmö the status of cives, inhabitants of a city.

Malmö was named Elbogen by German merchants of the Hanseatic League who thought that the coastline of Malmö looked like an elbow.

Last edited by Ann on Sat Sep 02, 2017 6:00 am, edited 1 time in total.
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Malmö, Malmö, if you're able, get Elbogen off the table!

Post by neufer » Fri Sep 01, 2017 11:26 pm

Ann wrote:
Malmö was named Elbogen by German merchants of the Hanseatic League who thought that the coastline of Malmö looked like an elbow. wrote:
elbow (n.) "bend of the arm," c. 1200, elbowe, from a contraction of Old English elnboga "elbow," from Proto-Germanic *elino-bugon, literally "bend of the forearm" (source also of Middle Dutch ellenboghe, Dutch elleboog, Old High German elinbogo, German Ellenboge, Old Norse ölnbogi). wrote:
<<This game can be played throughout the meal, and everyone is at risk! Every time someone spots someone with their elbows on the table, they chant the verse:

[list]Mable, Mable, if you're able,
Get your elbows off the table!
This is not a horse's stable
But a first-class dining table!

(Note: you can substitute the name of the accused instead of "Mable".)

The girl so named must stand up and her accuser must ask her to do some silly thing before she can sit back down again. Examples include reciting a nursery rhyme, clucking like a chicken, pouring new drinks for everyone at the table, etc. Just make sure that the requested action is not embarrassing for the child. Lots of fun!>>
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