moonsun (version 0.1.3)

rst: Rise, Transit and Set of specific coordinate points

Description

Compute Time of Rise, Transit and Set, and also azimuths of Rise and Set, for given positions, expressed in LOCAL SIDEREAL TIME.

Usage

rst(x, phi = getOption("latitude"))
sun.rst(jday = jd(), phi = getOption("latitude"))
moon.rst(jday = jd(), phi = getOption("latitude"))
"plot"(x, annotate = TRUE, ...)

Arguments

x

an object of class eqc

jday

Julian Day Number

phi

observer's latitude (default taken from options)

annotate

should the plot be annotated (set FALSE for large periods)

...

additional arguments passed to plot()

Value

An object of class "rst". If all values are -Inf, the object never rises above horizon. If rise and set are Inf, the object is always above horizon and only transit time is computed.

Details

The computed time is expressed as LOCAL SIDEREAL TIME (thus, longitude is not needed). If you want to convert it to local time, use as.lt().

The rst() function does not consider any motion of the object, so it shows some inaccuracy for Sun and very significant inaccuracy (even an hour) for the Moon. sun.rst() and moon.rst() function are designed for calculating the better rise, transit and set times of Sun and Moon by stepwise approximation.

Examples

options(latitude=51,longitude=22)
data(bright)
rst(bright)
as.lt(rst(bright))
as.lt(rst(planets()))
as.lt(moon.rst(jd(length=30)))