NUMBER@1 -RRB- / NUMBER@2 NUMBER@3 NUMBER@4 In astronomy , an epoch is a specific moment in time for which celestial coordinates or orbital elements are specified , and from which other orbital parametrics are thereafter calculated in order to predict future position .

In astronomy , an epoch -LRB- or sometimes epochal moment -RRB- is a moment in time for which the position or the orbital elements of a celestial body are specified .
