Find the next planetary apsis in a series

Given an aphelion event, this function finds the next perihelion event, and vice versa. This requires an apsis event obtained from a call to search_planet_apsis() or a previous call to next_planet_apsis().

Usage

next_planet_apsis(body, apsis)

Arguments

body

Integer constant identifying the planet. Use astro_body["PLANET_NAME"] where PLANET_NAME is one of: "MERCURY", "VENUS", "EARTH", "MARS", "JUPITER", "SATURN", "URANUS", "NEPTUNE", or "PLUTO". Must match the body passed into the call that produced the apsis parameter. Not allowed to be "SUN" or "MOON".

apsis

An apsis event (a list) obtained from a call to search_planet_apsis() or next_planet_apsis().

Value

A list with the same structure as returned by search_planet_apsis():

kind

An integer flag: 0 for perihelion, 1 for aphelion.

time

A POSIXct value representing the date and time of the next planetary apsis.

dist_au

The distance from the planet to the Sun in astronomical units.

dist_km

The distance from the planet to the Sun in kilometers.

See also

search_planet_apsis()

Examples

# Find successive apsis events for Mars
start <- as.POSIXct("2025-01-01", tz = "UTC")
apsis1 <- search_planet_apsis(astro_body["MARS"], start)
apsis2 <- next_planet_apsis(astro_body["MARS"], apsis1)
apsis3 <- next_planet_apsis(astro_body["MARS"], apsis2)