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SOLAR and LUNAR ECLIPSES : Part 3



EARLY HISTORY of
SOLAR and LUNAR ECLIPSES


Understanding the nature of observed eclipses was once fraught with the combination of superstition, fear and seemingly possible bad omens augured down on humankind from the immortal gods. The early ancient astronomers were unable to correctly interpret the real causes of the eclipse, let alone predict them.

Thales of Miletus (c.624-546 B.C.), an early Greek philosopher was first to be accredited to be able to roughly predict any observed solar or lunar eclipse. His best prediction was a total solar eclipse, as was told by the historian Herodutus of Halicarnassus (c.484-525 B.C.), was importantly instrumental in finally ending the six year war at the Battle of Halys (28 May 584 BCE.) between the Asia Minor Lydians and the invading middle-eastern Median Empire (Medes.) (Some sources say 585 BC., but the date and protracted path is given in the Five Millennium Canon of Solar Eclipses.) It seems that both sides saw the eclipse in the late afternoon as a bad omen, and they laid down their arms as to not anger either sides gods. Immediately after the battle an armistice was declared and a new treaty was enacted. From this solar eclipse this battle is one of the first historical dates we currently know with some certainty, as past eclipses be easily dated into the ancient distant past. The story may also be anecdotal for other reasons not passed down to us in the present day.

Later in about 455 B.C., the Greek philosopher, Anaxagoras of Clazomenæ (c.500-429BC.) certainly knew the correct explanation, because he realised that the round shape of the lunar eclipse shadow was the spherical shape of the Earth projected into space. By 150 BC., the Father of Astronomy astronomer, Hipparchus of Rhodes (Hipparchos) (c.190-120 BC.) had first correctly describe the nature and causes of all types of eclipses.

Others may have understood this fully, or only partly, but unfortunately most of these earliest records have been either destroyed or are now lost to us forever.

The oldest known written solar eclipse, at least with any certainty, was made from the city of Ugarit in Mesopotamia on 3rd May 1375 BC. The oldest recorded lunar eclipse we have at the moment was in 1136 B.C., just before the time of the Trojan Wars between isolated states of Greece and Asia Minor.

Various solar eclipses were often recorded in the ancient literature. These can be divided into several different types, as first employed by Robert R. Newton in 1969. (Geophys., J.RAS., 14, pg.505-539 (1968)) Such eclipses are importance as they can set precise dates for the ancient historical events that occurred around some important period or war. Historical astronomers have made detailed studies of the ancient records, sometimes called archeoastronomy, for precisely this reason. Sadly we know very little about the circumstances of these early eclipses because of the poorly presented and often nondescript text that has been passed down to us.


Magical eclipses have been purely fabricated to meet some significant event or war in history. An example was the solar eclipse of 2nd October 480 BC., when the march of the Persia king Xerxes on Boeotia in Greece was suddenly turned back because of the occurrence of an eclipse, though some have interpreted this as the reason for the beginning of the invasion of Greece. Another was the solar eclipse reported by the poet Archilochus of Paros (680-645 BC.) that presumably occurred on 6th April 648 BC., over the Aegean island of Thasos near the Macedonian coast.

Assimilated eclipses are ones thought to have been date shifted purposely by the author to meet certain political events or wars of particular significance. We think that some of the famous battles were staged around the time of some eclipse, whose only reason was to frighten off the opposing side. Both the Greeks and Romans may have used this idea to their own advantages. Probably, the most famous example was during Alexander the Great in his final Battle of Issus against the Persian army on 26th September 331 BC. Fighting in this battle was the morning after a total lunar eclipse. Alexander claimed to his men that it meant good fortune. The Persians shrank in fear and terror, interpreting this as a sign of a coming defeat. Historians have often said that this may have been the story created after the battle to show that the gods were actually on the side of the Greeks.

Literary eclipses are ones that are pure fiction, created solely for the prestige of the author. An example is the presumed observed eclipse was during 71 AD. in Italy. It never happened!


SAROS and PREDICTING ECLIPSES

True eclipses are ones that occur on the dates that can be pre-calculated. An example was the solar eclipse that occurred in Thebes on 13th July 364 B.C. The main significance of this eclipse was that it changed the mind of king Alexander of Pheræ, so that he decided to attack the city of Thessaly — in the northern Greece independent state of Thiazole. (However, R. Newton has recently stated some doubt in this eclipse, as five other eclipses are also possible.)

One of the first means of predicting eclipses was the discovery of the Saros Cycle or Saros, which was discovered, by unknown means, by the Greeks and Chaldaeans. In the 5th Century BC, the Greek astronomer Anaxagoras announced that he could predict eclipses using the Saros Cycle, but the Athenians at the time considered this blasphemous against the gods and rejected the whole idea out of hand. He was later proven to be right. Yet some historians currently believe the ancient discovery of the Saros might be just coincidence.

Today, the Saros refers to the period between successive eclipses whose predictable pattern recurs in periods of about 6585.32 days or 18 years 10 days and 8 hours, and corresponds to exactly 223 successive lunar orbits or so-called lunations. We know that the Saros is caused by the lunar inclination to the ecliptic — the plane that the planets follow. When the lunar position crosses the elliptical plane, it varies or precesses during every Saros, and eventually after the period returns to the same starting point when it again crossed the ecliptic. In addition, eclipses are related to the eclipse year, based on the draconic month of the Moon, when the Sun coincides to the Moons ascending node. Successive eclipses each Saros cycle occurs one-third further around the Earths circumference, adding the eight extra hours, and therefore, once every 54 years 31 days, another similar eclipse will roughly occur near the same place of the previous eclipse.

Example of the Saros Solar Eclipses

ECLIPSES in SAROS
No.139
Eclipse
Date
Duration
Totality
Location
18th March 1988 03m 36s Indonesia, Northern Pacific
29th March 2006 04m 07s Africa, Western Europe
08th April 2024 04m 28s Mexico, Southern North America
20th April 2042 04m 51s China, Japan, S.E. Asia
30th April 2060 05m 15s Northern Africa, Turkey
11th May 2078 05m 40s Mexico, Southern North America
22nd May 2096 06m 06s Indonesia, Northern Pacific
03rd June 2114 06m 32s Northern Africa, Turkey

Details of a Saros


ECLIPSES in SAROS
No.139
Place In Saros Date Eclipse
Type
Duration Location
First Eclipse 17th May 1501 Partial -- North Pole
First Eclipse 17th May 1627 Hybrid 00m 00s North
Longest Eclipse 11th August 2186 Total 07m 29s N.South America
Last Eclipse 16th July 2601 Hybrid 00m 35s South
Last Eclipse 03rd July 2763 Partial -- South Pole
Within Saros 139, there are;
In all there are 71 Eclipses, being;
6 Partial, 0 Annular, 43 Total and 12 Hybrid
Saros 139 lasts over 1262.11 years
Reference : Fred Espanak Eclipse Web Site


Important Disclaimer

The user applying this data for any purpose forgoes any liability against the author. None of the information should be used for either legal or medical purposes. Although the data is accurate as possible some errors might be present. The onus of its use is placed solely with the user.


Last Update : 26th November 2012

Southern Astronomical Delights © (2012)

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