Eclipses

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LUNAR ECLIPSES on Earth,
1001 BC to AD 2500
revised November 2003

Please send comments to Felix Verbelen

The presented datafile list includes all lunar eclipses visible on Earth during the period 1001 BC to AD 2500.

Several excellent catalogues of lunar eclipses already exist, for example [1], but these use Ephemeris Time (or Terrestrial Time).
Our list is based on Universal Time andthere for tends to be directly usable for historical research.

Calendar
Up till October 4th 1582, dates are according to the Julian calendar.
After that date we used the Gregorian calendar.
Years before AD 1 are given according to the astronomical notation.
This means that year 1 is preceded by year 0, which is preceded by year -1.
So, year 1 = AD 1, year 0 = 1 BC, year -1 = 2 BC, and soon.

Time indications
All times are expressed in Universal Time (UT).
In a number of countries UT is still referred to as GMT (Greenwich Meridian Time).

In order to derive the local mean solar time for some location on Earth, a correction has to be applied to the given times.
If the geographical longitude of the observer's location is taken positive for longitudes West of Greenwich andnegative East of Greenwich, the correction to be applied equals:

     correction (hours) = - geographical longitude (degrees) / 15

For a number of major Mesoamerican locations corrections are tabulated hereafter:

| |
|Location |correction |
| |(hours and minutes) |
|CHICHEN ITZA|- 5 h 54 m |
|CHOLULA |- 6 h 33 m |
|COPAN |- 5 h 57 m |
|LA VENTA |- 6 h 16 m |
|MONTE ALBAN |- 6 h 27 m |
|PALENQUE |- 6 h 08 m |
|PIEDRAS NEGRAS|- 6 h 05 m |
|QUIRIGUA |- 5 h 56 m |
|TENOCHTITLAN |- 6 h 36 m |
|TEOTIHUACAN |- 6 h 35 m |
|TIKAL |- 5 h 59 m |
|TULA |- 6 h 37 m |
|UXMAL |- 5h 59 m |
|YAXCHILAN |- 6 h 04m |

These corrections have to be added to the tabulated times in order to obtain the mean local time at the considered location.

Example:
     According to our list, a total lunar eclipse was at maximum on June 18, 1201 AD at 2 h 47 m UT.     At that moment the local mean solar time at Tikal was

          2 h 47 m - 5 h 59 m (+ 24 h) = 20 h 48 m (of the previous day)

     To obtain a list of the lunar eclipses that were actually visible in the Mesoamerican region during     the period AD 1 to AD 1600 see our datafile of Lunar Eclipses in Mesoamerica.

Method of calculation - Delta T
For the calculations of the eclipses we started from the classical theories [2 to 8], not taking intoaccount small periodical variations in the solar and lunar orbits.
To take into account the general deceleration of the Earth's rotation and long-term periodic irregularities of this rotation, this means to convert Terrestrial Time (TT) to Universal Time (UT), several equations have been proposed, among others by Spencer Jones [8], L.V.Morrison and F.R. Stephenson [9], F.R.Stephenson and L.V.Morrison [10], F.R.Stephenson and M.A. Houlden [11], and F.R.Stephenson [12].

We used the following equations   [11] :

     till AD 948:
     DeltaT = 1830 - 405*E+46.5*E^2
     where E = Julian centuries since AD 948

     after AD 948:
     DeltaT = 22.5 t^2
     where t = Julian centuries since AD 1850

The uncertainties with respect to the Earth's rotation do not affect the accuracy...
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