Editing Tritos

{{Short description|Eclipse cycle}}
{{no footnotes|date=October 2024}}
[[File:Tritos saros lunar series 1000-2500.png|220px|thumb|A graph of lunar eclipses, grouped by their [[Saros cycle]] and Tritos cycle]]

The '''tritos''' is an [[eclipse cycle]] of 3,986.628 days (about 10 years, 11 months).
It corresponds to:
*135 [[synodic month]]s 
*146.50144 [[draconic month]]s
*11.50144 eclipse years (23 [[eclipse season]]s)
*144.68135 [[anomalistic month]]s.

The length of the tritos is equal to the length of the [[inex]] minus the length of the [[saros (astronomy)|saros]] eclipse cycles.  Therefore, eclipses that occur 1 tritos apart (i.e. both eclipses belong to the same tritos series), belong to two different saros series with series numbers that differ by one.

The [[pre-Columbian]] [[Maya civilization|Maya]] used a calculation in their own observations of eclipse cycles in which a period of three tritoses (or tritoi) was approximated by 11960 days, based on 46 periods of their [[tzolkin|tzolk'in]] calendar (i.e. 46 × 260 days). The number of ''anomalistic months'' in a tritos (144.68), having a fraction near {{frac|2|3}}, means every third eclipse is in nearly the same position in the elliptical orbit, so eclipses will have similar timing and total versus annular quality.

Solar and lunar eclipse event dates will repeat on this cycle for about 700 years.

== Example solar Tritos series ==
{{Solar Tritos series 2002 June 10}}

== Example lunar Tritos series ==
{{July 2000 lunar eclipse Tritos series}}

== See also ==
* [[Eclipse cycle]]
* [[Inex]] - related series

== References ==
* Mathematical Astronomy Morsels, Jean Meeus, Willmann-Bell, Inc., 1997 (Chapter 9, p.&nbsp;51, Table 9.A Some eclipse Periodicities)

[[Category:Eclipses]]