get_moon: Calculate moon exposure for a given time period

In adamdsmith/nrsmisc: Miscellaneous functions for work

Description

This function calculates the proportion of the moon's face that is illuminated, and whether the moon is above horizon at a given location, for a user-specified number of hours from a provided POSIXct object. Specifically, it sums the proportion illuminated at the midpoint of every hour, conditional on the moon being above local horizon. Thus, the returned value ranges from zero (new moon or moon not above horizon) to exp_hrs (full moon above horizon for the entire time from datetime to datetime + exp_hrs).

Usage

get_moon(datetime, lon, lat, exp_hrs = 6)

Arguments

datetime	POSIXct vector of datetimes from which moon exposure should be calculated
lon	numeric scalar of position longitude (decimal degrees; WGS84)
lat	numeric scalar of position latitude (decimal degrees; WGS84)
exp_hrs	integer of number of hours post-datetime to calculate exposure

Examples

get_moon(as.POSIXct(Sys.time()), -83, 34, 12)
# For fun, plot daily moon exposure for next lunar cycle
next_cycle <- as.POSIXct(seq.Date(Sys.Date(), by = 1, length.out = 28))
plot(next_cycle, get_moon(next_cycle, -83, 34, 24))

adamdsmith/nrsmisc documentation built on Aug. 13, 2019, 2:14 p.m.