Key to Catalog of Lunar Eclipse Saros Series

Five Millennium Canon of Lunar Eclipses [Espenak and Meeus]

Introduction

Each line in the tables of the lunar eclipse catalog corresponds to a single lunar eclipse and provides concise parameters to characterize the eclipse. The calendar date and Dynamical Time of the instant of greatest eclipse[1] are given along with the adopted value of ΔT. The lunation number (since 2000 Jan 06) and the Saros series are listed along with the eclipse type (N=Penumbral, P=Partial, or T=Total). The quincena solar eclipse parameter identifies the type of solar eclipse that precedes and/or succeeds a lunar eclipse. Gamma is the distance from the Moon's center to the axis of Earth's shadow cones at greatest eclipse, while the penumbral and umbral eclipse magnitudes are defined as the fraction of the Moon's diameter immersed in each shadow at that instant. The duration of the penumbral, partial, and total eclipse phases are given in minutes. Finally, the geographic latitude and longitude are given for the location where the Moon lies in the zenith at greatest eclipse. A more detailed description of each field in the tables appears in the Key below.

The data presented in the catalog were previously published in the Five Millennium Canon of Lunar Eclipses: -1999 to +3000.


Footnotes

[1] Greatest eclipse is defined as the instant when the center of the Moon passes closest to the axis of Earth's umbral shadow.


Key to Catalog of Lunar Eclipses

Column     Heading     Definition/Description
          
   1       Catalog     Sequential number of the eclipse in the catalog links to
           Number      the figure published in the 
                       Five Millennium Canon of Lunar Eclipses: -1999 to +3000. 

   2      Calendar     Calendar Date at instant of Greatest Eclipse. 
            Date       Gregorian Calendar is used for dates after 1582 Oct 15.  
                       Julian Calendar is used for dates before 1582 Oct 04.   

   3         TD of     Dynamical Time (TD) of Greatest Eclipse, the instant 
           Greatest    when the distance between the center of the Moon and the 
           Eclipse     axis or EarthÕs umbral shadow cone reaches a minimum.

   4         ΔT        Delta T (ΔT) is the arithmetic difference between 
                       Dynamical Time and Universal Time. It is a measure of 
                       the accumulated clock error due to the variable 
                       rotation period of Earth.

   5        Luna       Lunation Number is the number of synodic months since 
             Num       New Moon of 2000 Jan 06. The Brown Lunation Number 
                       can be determined by adding 953.

   6        Saros      Saros series number of eclipse.
             Num       (Each eclipse in a Saros is separated by an interval
                        of 18 years 11.3 days.)

   7        Ecl.       Eclipse Type where:
            Type         N  = Penumbral Lunar Eclipse.
                         P  = Partial Lunar Eclipse (in umbra).
                         T  = Total Lunar Eclipse (in umbra).

                       Second character in Eclipse Type:
                         "m" = Middle eclipse of Saros series.
                         "+" = Central total eclipse 
                               (Moon's center passes north of shadow axis).
                         "-" = Central total eclipse 
                               (Moon's center passes south of shadow axis).
                         "x" = Total penumbral lunar eclipse.
                         "b" = Saros series begins (first penumbral eclipse in series).
                         "e" = Saros series ends (last penumbral eclipse in series).
                         
   8         QSE       Quincena Solar Eclipse Parameter identifies the type of 
                       solar eclipse that precedes and/or succeeds a lunar eclipse.
                       
                       Solar eclipse types:
                       p = partial solar eclipse (MoonÕs penumbral shadow traverses Earth).
                       a = annular solar eclipse (MoonÕs antumbral shadow traverses Earth).
                       t = total solar eclipse (MoonÕs umbral shadow traverses Earth).
                       h = hybrid solar eclipse (MoonÕs umbral and antumbral shadows 
                           traverse different parts of Earth; 
                           also known as an annular-total eclipse).
                         
   9        Gamma      Distance from the center of the shadow cone axis 
                       to the center of the Moon  (in units of Earth's equatorial radii) 
                       at the instant of greatest eclipse.

  10        Pen.       Penumbral magnitude is the fraction of the Moon's diameter
            Mag.       immersed in the penumbra at the instant of greatest eclipse.
                       (equal to the distance measured from the edge of the penumbral 
                       shadow to the edge of the Moon deepest in the penumbra).

  11        Umb.       Umbral magnitude is the fraction of the Moon's diameter
            Mag.       immersed in the umbra at the instant of greatest eclipse.
                       (equal to the distance measured from the edge of the umbral 
                       shadow to the edge of the Moon deepest in the umbra).
                       
  12   Eclipse Phase   Duration of penumbral phase of a lunar eclipse; equal to
         Duration      the time interval between first and last contact of the Moon 
            Pen.       with the penumbral shadow (= P4 - P1).
            
  13   Eclipse Phase   Duration of parial phase of a lunar eclipse; equal to
         Duration      the time interval between first and last contact of the Moon 
            Par.       with the umbral shadow (= U4 - U1).
            
  14   Eclipse Phase   Duration of total phase of a lunar eclipse; equal to
         Duration      the time interval between second and third contact of the Moon 
            Tot.       with the umbral shadow (= U3 - U2).
                    


Eclipse Predictions

The coordinates of the Sun used in these predictions are based on the VSOP87 theory [Bretagnon and Francou, 1988]. The Moon's coordinates are based on the ELP-2000/82 theory [Chapront-Touze and Chapront, 1983]. For more information, see: Solar and Lunar Ephemerides. The revised value used for the Moon's secular acceleration is n-dot = -25.858 arc-sec/cy*cy, as deduced from the Apollo lunar laser ranging experiment (Chapront, Chapront-Touze, and Francou, 2002).

The largest uncertainty in the eclipse predictions is caused by fluctuations in Earth's rotation due primarily to tidal friction of the Moon. The resultant drift in apparent clock time is expressed as ΔT and is determined as follows:

  1. pre-1950's: ΔT calculated from empirical fits to historical records derived by Morrison and Stephenson (2004)
  2. 1955-present: ΔT obtained from published observations
  3. future: ΔT is extrapolated from current values weighted by the long term trend from tidal effects

A series of polynomial expressions have been derived to simplify the evaluation of ΔT for any time from -1999 to +3000. The uncertainty in ΔT over this period can be estimated from scatter in the measurements.


Acknowledgments

Special thanks to Jean Meeus for providing the Besselian elements used in the lunar eclipse predictions.

All eclipse calculations are by Fred Espenak, and he assumes full responsibility for their accuracy. Some of the information presented on this web site is based on data originally published in Five Millennium Canon of Lunar Eclipses: -1999 to +3000 and Five Millennium Catalog of Lunar Eclipses: -1999 to +3000.

Permission is freely granted to reproduce this data when accompanied by an acknowledgment:

"Eclipse Predictions by Fred Espenak and Jean Meeus (NASA's GSFC)"


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2009 Sep 29