equinoxes and solstices
Astronomical Algorithms - Second Edition - Jean Meeus
Chapter 27 : Equinoxes and Solstices
| Y (Table 27.A/27.B)= |
Y |
| |
|
| JDE0 March = |
JDE0 March |
| JDE0 June = |
JDE0 June |
| JDE0 September = |
JDE0 September |
| JDE0 December = |
JDE0 December |
| |
|
| T March = |
T March |
| T June = |
T June |
| T September = |
T September |
| T December = |
T December |
| |
|
| delta lambda March = |
delta lambda March |
| delta lambda June = |
delta lambda June |
| delta lambda September = |
delta lambda September |
| delta lambda December = |
delta lambda December |
| |
|
| S March = |
S March |
| S June = |
S June |
| S September = |
S September |
| S December = |
S December |
| |
|
| JDE March = |
JDE March |
| JDE June = |
JDE June |
| JDE September = |
JDE September |
| JDE December = |
JDE December |
| |
|
| Method 1 = Simplified method as in example 27.a |
| March Equinox date/time TD = |
March Equinox date/time TD |
| June Solstice date/time TD = |
June Solstice date/time TD |
| September Equinox date/time TD = |
September Equinox date/time TD |
| December Solstice date/time TD = |
December Solstice date/time TD |
| |
|
| Method 2 = More accurate method (partly VSOP87) as in example 27.b |
| March equinox date/time TD = |
March equinox date/time TD |
| June solstice date/time TD = |
June solstice date/time TD |
| September equinox date/time TD = |
September equinox date/time TD |
| December solstice date/time TD = |
December solstice date/time TD |
| |
|
| Determining Delta T (UT = TD - Delta T) |
| |
|
| Delta T in seconds for the given year = |
Delta T |
| |
|
| Method 1 = simplified method as in example 27.a |
| March Equinox date/time UT = |
March Equinox date/time UT |
| June Solstice date/time UT = |
June Solstice date/time UT |
| September Equinox date/time UT = |
September Equinox date/time UT |
| December Solstice date/time UT = |
December Solstice date/time UT |
| |
|
| Method 2 = More accurate method (partly VSOP87) as in example 27.b |
| March equinox date/time UT= |
March equinox date/time UT |
| June solstice date/time UT = |
June solstice date/time UT |
| September equinox date/time UT = |
September equinox date/time UT |
| December solstice date/time UT = |
December solstice date/time UT |
Remarks
Delta T based on the Five Millenium Canon of Lunar Eclipses (Espenak and Meeus)
Delta T = TD - UT or UT = TD - Delta T
TD = Dynamical Time
UT = Universal Time = Greenwich Civil Time
