Archaeological and Early Historical Contexts
This section is intended to
convey a general idea of the current history of eclipse knowledge.
Astronomical data concerned with the cosmic objects which move along
the ecliptic, the sun, moon, and the visible planets, is known from
prehistoric cultures. The most remote eclipse record is likely a
Rg-Veda description of a solar eclipse observed by Atri about 3,928
B.C. Before inventing paper, the Chinese kept records on bones and
shells. Li Shu wrote about astronomy around 2,650 B.C. and observatory
buildings are known by 2,300 B.C. Inscribed bones and tortoise shells
from the Shang dynasty reference solar eclipses. From the Chou dynasty
and the Warring States period, over 40 solar eclipse observations are
recorded from 720 BC onward, the earliest recorded series.
"... the Spring and Autumn Annals records as many as
36 eclipses of the Sun. This series of observations, which
commences with the event of Feb 22 in 720 BC, is the earliest from any
part of the world ... prove to be in exact accord with those of
eclipses listed in modern tables." Stephenson (1997:221-223)
In Anyang, five recorded solar eclipses
between 1,161 BCE and 1,226 BCE are known. Based on a Chinese
inscription, astronomers from NASA's Jet Propulsion Laboratory (JPL)
fixed the exact date and path of a solar eclipse in the year 1,302 B.C.
to determine delta T, a measure of the slowing of the earth’s rotation.
They concluded the length of each day was 0.0047 seconds shorter in
An early Mesopotamian record
of a total solar eclipse at Ugarit is from May 3, 1,375 B.C. Clay
tablets with astronomical observations survive from Mesopotamian
civilizations. Babylonian astronomical records on tablets dating from
1,700 B.C. report the motions of Mercury, Venus, and the Moon. Later
records include a total solar eclipse on July 31, 1,063 B.C. and the
well-documented Nineveh eclipse of June 15, 763 BC, recorded by the
Assyrians. Diodorus of Sicily suggests ziggurats were the observation
platforms. Continuous usage and layered rebuilding of ziggurats dates
to the dawn of civilization.
Babylonian civil calendar was regulated by a Metonic cycle. The oldest
record of the 223 moon Saros interval is Mesopotamian. The
historical astronomy of Mesopotamia evidences, around 400 B.C., the
celestial zodiac of 12 signs of 30 degrees each, a lunisolar calendar,
a lunar synodic (full moon cycle) value of 29.530592644 days (as a
fraction), knowledge of the Metonic and Saros eclipse cycles, eclipse
record keeping, and use of arithmetical progressions for accurate
achievements evidence a long history of observations and the most
advanced astronomy documented for the time. A great number of
Mesopotamian astronomical texts from the last three centuries B.C.
include evidence of sexagesimal place value notation, eclipse records,
and the use of zero.
the most accurate and reliable data from the whole of the
pre-telescopic period." Stephenson (1997:456)
Astronomy also flourished in
the Middle East and India during Europe's Dark Age. The 500 A.D. Indian book on astronomy, The Àryabhatiya of Àryabhata,
precise sidereal ratio of the readily-observed earth
lunar orbits. Àryabhata provided
geometrical methods for calculating
by the Anikythera mechanism, a
sophisticated mechanism dating from the 2nd century B.C and
discovered near Crete in 1,900 by sponge
divers. The mechanism's dials include a Metonic cycle calendar and a Saros eclipse-prediction dial
with prediction glyphs. A Greek text by
Archimedes on astronomical mechanisms has
not survived. Homer's
The Odyssey reports the 1,178 B.C. solar
eclipse, "... the Sun has perished out of heaven, and an evil mist
hovers over all."
May 28, 585 B.C. total eclipse predicted by
Thales in Asia Minor is the beginning of the Greek Classical Period. Greek historical documents evidence the role of Egyptian and Mesopotamian astronomy in Greek science. Ptolemy's Almagest included
Babylonian observations of six solar eclipses, the earliest eclipse
dating to 721 B.C. The Almagest also includes Egyptian
sidereal observations of the moon and employs a Callippic calendar to
Greek astronomer Meton and his associate Euctemon instituted a
19-year-eclipse calendar in Athens on the summer solstice of 432 B.C. Callippus' calendar cycle began
astronomically in 330 B.C. on a start date
when summer solstice and the lunar month beginning nearly coincided.
at 1:44 A.M. U.T. while solstice
was close to midnight, less than two hours earlier. Geminus reports
Callippus corrected the 19-year cycle, deducting one day every four
Metonic periods. Apparently, Callippus knew of the one day difference
between days per orbit and days per year every 4 Metonic cycles. This
infers Callippus observed the Metonic cycle against sidereal reference.
Aristarchus (Aristarchos) of Samos proposed a heliocentric solar system
in 297 B.C. In the second century B.C. Hipparchos understood the
elliptic orbit of the moon and precession of the equator.
"... the god
visits the island every nineteen years, the period in which the return
of the stars to the same place in the heavens is accomplished."
Diodorus Siculus "the Greeks [who] use
the nineteen-year cycle ...
are not cheated of the truth." Diodorus Siculus
365.25636 days per orbit = 27,759.48 days
76 * 365.24248 days per year = 27,758.43 days
Greek records indicate an
Egyptian practice of sidereal astronomy. Diodorus noted ancient
Egyptian astronomers predicted solar eclipses. Thales, who brought
Egyptian land surveying rules to the Greeks—the basis of Euclidian
geometry, predicted the total solar eclipse on May 28, 585 B.C.
According to historical documents, the Greeks had not predicted a solar
eclipse prior to Thales predicting the eclipse near Miletus in Asia
Minor. Thales studied mathematical and astronomical knowledge in Egypt
before predicting the Miletus eclipse. Unfortunately, burning the Great
Library in Alexandria destroyed untold Egyptian history.
of the first period
according to Callippus, on Elaphebolion 15, which is Tybi 5, as the
third hour was beginning, the moon overtook Spica with the middle of
the part of its rim that points towards the equinoctial rising, and
Spica traversed it, cutting off exactly one third of its diameter on
the north side."
The libraries in the
Americas were also burned. Surviving Maya writing provides the best
evidence of astronomy in pre-Hispanic America. Mayan symbols of the sun
and the moon are unequivocally known. The 405 lunation eclipse cycle of
11,960 days is known from the Dresden Codex (810 nodal periods = 879
synodic periods or 1.0 : 1.000 010). From Copan Stelae 3 and A, the
Metonic eclipse cycle is reported as 6,940 days, equaling 19 solar
years and 235 moons. A sequence of bar and dot numerators in the
Fejérváry Codex, pages 15 to 22, totaling 6,940 days, one
Metonic cycle, was the first notice of this cycle in iconographic
texts. The Metonic cycle also appears in the histories of Tilantongo
and the Mixteca.
Knowledge of the eclipse cycle is
evidenced in the House of the Sun at Palenque, dedicated in A.D. 692.
The Palenque ratio is 81 moons to 2,392 days. Maya mathematics employed
large integers instead of decimal notation. The 81 to 2392 ratio
expresses a value of 29.530864 days per lunar cycle, 0.00028 days less
than the present cosmic period. Longer Maya astronomical count intervals accurately equating solar
and lunar orbits indicate early astronomical understandings.
Evidence of lunar dates begin at A.D. 357 in an inscription from
Uaxactun, bearing a Long Count date of 18.104.22.168.0. A vase from Uaxactun
places the origin of a lunar calendar prior to A.D. 42.
In the Dresden Codex
the Saros cycle was recognized. The most important codex is the Dresden
with its eclipse series table. Eclipse prediction infers a certain
level of knowledge, including the length of the lunar month, the
interval between lunar nodes and the ecliptic limit for solar eclipses.
Evidence of eclipse prediction infers this knowledge existed. About 200 lunar observations are known in Maya