day_in_synodic_cycle {emoji} | R Documentation |
This uses the approximation described in the
lunar phase wikipedia page, i.e.
the number of days since 1900/01/01
modulo the length of
a synodic month (29.530588853
days)
day_in_synodic_cycle(date)
date |
a date |
day_in_synodic_cycle(Sys.Date())