calendar_change: Solar astronomy using Meeus' algorithm

Description

The exact julian day computation is adapted from ode::julianDay() and tested againts test cases in Redas and Andreas (2008, table A4.1) for validity up to year 4712 BC.

Usage

calendar_change
julian_day(time)
julian_day_fast(time)
julian_century(time)
geom_mean_lon_sun(x)
geom_mean_anom_sun(x)
eccent_earth_orbit(x)
sun_eq_of_ctr(x, anom)
sun_rad_vector(eccent, anom)
sun_app_lon(x, lon)
mean_obliq_eclip(x)
obliq_corr(x, eclip)
sun_rt_ascen(app.lon, obliq.corr)
sun_decline(app.lon, obliq.corr)
var_y(obliq.corr)
eq_of_time(mean.lon, eccent.earth, anom.mean, var.y)
ha_sunrise(lat, decline, nag = 0)
solar_noon(lon, eq.of.time)
sunrise(noon, ha.sunrise)
sunset(noon, ha.sunrise)
sunlight_duration(ha.sunrise, unit.out = "hours")
solar_datetime(time, lat, lon, eq.of.time)
solar_tod(time, lat, lon, eq.of.time)
hour_angle(solar.time)
zenith_angle(lat, hour.angle, decline)
elevation_angle(lat, hour.angle, decline)
atm_refraction_approx(elevation.angle)
azimuth_angle(lat, hour.angle, zenith.angle, decline)

Value

datetime

numeric

Format

An object of class POSIXct (inherits from POSIXt) of length 1.

Arguments

time: dateTime
x: numeric Julian century
anom: numeric Solar anomaly in degrees
eccent: numeric Eccentricity of Earth orbit
eclip: numeric Ecliptic
app.lon, obliq.corr, mean.lon, nag, decline: numeric Angles in degrees
lat, lon: numeric Geographic coordinates in degrees
eq.of.time, ha.sunrise, noon: numeric
zenith.angle, elevation.angle, hour.angle: numeric Angles in degrees

Details

Low level functions based on NOAA's Excel worksheet