As an example, orbital elements, especially osculating aspects for slight planets, are routinely presented with reference to 2 dates: to start with, relative to a new epoch for all of The weather: but several of the details are depending on a chosen coordinate method, then it is actually typical to specify the coordinate process of a regular epoch

Epoch as opposed to equinoxDate-references for coordinate systemsEpochs and intervals of validityChanging the regular equinox and epochSpecifying an epoch or equinoxBesselian yearsJulian yrs and J2000Epoch on the daySee alsoReferencesNotesCitationsSourcesFurther readingExternal back linksAstronomical portions may be laid out in any of numerous ways