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Marcus Vizualizare profil forumist	27 Jan 2004, 08:30 PM Mesaj #1
forumistul sahist - cel mai pasionat forumist Grup: Moderator Mesaje: 3.308 Inscris: 26 January 04 Din: Bucuresti / Braila Forumist Nr.: 1.995	Am hotarat sa deschid acest topic pt cei interesati de astronomie si care vor sa afle mai multe despre aceasta stiinta atat de putin luata in serios de multi romani in ziua de azi. Cu ajutorul dumneavoastra, vom afla impreuna cunostintele de baza ale acestei stiinte atat de frumoase si...exacte. Mesajul meu este acela de a va indemna sa cunoasteti date (cel putin minimale), un scurt istoric al astronomiei, legile care stau la baza astronomiei, s.a. Cei interesati sunt bine veniti. -------------------- * * * Nu lãsa visele sã piarã, pentru cã dacã visele mor, viaþa nu este decât o pasãre cu aripi rupte care nu mai poate sã zboare! (Langston Hughes) * * * Turneul de Sah HanuAncutei 2012

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dead-cat

5 May 2004, 01:39 PM

Mesaj #2

Domnitor

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http://news.independent.co.uk/world/scienc...sp?story=517627

QUOTE

[...]
In 1959, the chart was dated by the science historian Joseph Needham to about AD940, but it was later re-evaluated by a Chinese scholar who dated it to between AD705 and AD710.

Two French academics now believe the star chart is even older and may have been drawn as early as the start of the Tang period, AD618.

Jean-Marc Bonnet-Bidaud of the French Atomic Energy Agency and Françoise Praderie of the Observatoire de Paris also believe that the Dunhuang manuscript is a copy of a much older map that has since been lost to antiquity.

In a description for the British Library's exhibition on the Silk Road, which opens on Friday, the scientists say: "The overall quality of the document clearly demonstrates a mature technique so the chart was probably produced as a copy of an earlier existing document."

M. Bonnet-Bidaud said: "Curiously, the information in the texts accompanying the charts is extremely similar in style and content to the notations given in [a] much earlier astronomical text, the Yue Ling or 'Monthly Ordinances', dated approximately 300BC.
[...]

QUOTE

[...]
One of the technical problems of producing a complete star chart of the sky is the difficulty of converting the three-dimensional sphere of space into a two-dimensional plan, M. Bonnet-Bidaud said. "A freehand drawing based on direct vision will be highly distorted since the eyes see only a limited portion of the sky at a time," he said.

One possibility is that the early Chinese astronomers used a method of projecting the sky onto a cylinder using a Mercator-like projection system - the traditional way of making a two-dimensional map of the spherical Earth by sacrificing accuracy at the poles for the sake of accuracy nearer the equator.

Mme Praderie said it is likely that the stars nearer to the poles were drawn separately to overcome the distortions that would otherwise be introduced using such a projection method. "The composition of the chart and its presentation are modern," she said. "They are similar to our modern geographical maps of the Earth."

The origin and use of the star chart remains a mystery, although it is likely to have had a military purpose or perhaps to have been a guide to travellers, Mme Praderie said. It was almost certainly used for uranomancy, the divination of events by consulting the heavens, which is supported by texts on cloud divination preceding the star charts, she said.

"The long-tradition in China of searching the sky for celestial omens has, therefore, led to an early and unsurpassed precision in star catalogues," she said.

QUOTE

Intocmirea unei asemenea harti in sec 7 i.e.n. a ramas un mister pentru astronomi.

originea si scopul hartii sunt un mister, dar nu pt. astronomi ci pentru istorici. obiectele notate nu sunt invizibile pt. ochiul liber ci greu vizibile. ca si Andromeda de altfel.

articolul sustine ca harta (cea presupus originala, nu cea gasita) e datata aprox. 300 BC.

--------------------

Black holes are where God divided by zero.

Mesaje in acest topic

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dead-cat http://news.independent.co.uk/world/scienc...sp?st... 5 May 2004, 01:39 PM

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Catalin QUOTE Dar Einstein a observat (nu stiu cum) ca di... 16 May 2004, 02:14 PM

dead-cat QUOTE Current physics (called quantum field theor... 16 May 2004, 03:33 PM

Catalin Dead-cat, chiar in link-urile tale (link-ul 2 mai ... 16 May 2004, 05:12 PM

dead-cat indeed, dar nu e o speculatie "neserioasa... 16 May 2004, 05:16 PM

Catalin QUOTE indeed, dar nu e o speculatie "neserio... 16 May 2004, 05:27 PM

dead-cat QUOTE Heh, apropos de tahioni, tu esti nou pe-aic... 16 May 2004, 08:41 PM

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Marcus Constelatia Perseidelor 13 Aug 2004, 05:31 PM

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