astro_search_sun_longitude

Searches for the time when the Sun reaches a specified apparent ecliptic
longitude as seen from the center of the Earth.

Provides access to the 'Astronomy Engine' C library
(<https://github.com/cosinekitty/astronomy>) by Don Cross. The library
calculates positions of the Sun, Moon, and planets, and predicts
astronomical events such as rise/set times, lunar phases, equinoxes,
solstices, eclipses, and transits. It is based on the 'VSOP87' planetary
model and is accurate to within approximately one arcminute. This package
bundles the single-file C source so that other R packages can link against
it via 'LinkingTo' without shipping their own copy.

Mitchell O'Hara-Wild

astronomyengine

R Bindings to the 'Astronomy Engine' C Library

Don Cross

astro_search_sun_longitude function

<dl><dt>target_lon</dt>
<dd>Numeric. The desired ecliptic longitude in degrees,
relative to the true equinox of date. Must be in the range [0, 360).
Conventional values: 0 = March equinox, 90 = June solstice,
180 = September equinox, 270 = December solstice.</dd>
<dt>start_time</dt>
<dd>POSIXct. The date and time for starting the search.</dd>
<dt>limit_days</dt>
<dd>Numeric. The number of days to search forward from
<code>start_time</code>. Recommended range: 1 to 10 days.</dd></dl>

Arguments

Search for Sun longitude — astro_search_sun_longitude

<dl>

<dt>target_lon</dt>
<dd>Numeric. The desired ecliptic longitude in degrees,
relative to the true equinox of date. Must be in the range [0, 360).
Conventional values: 0 = March equinox, 90 = June solstice,
180 = September equinox, 270 = December solstice.</dd>


<dt>start_time</dt>
<dd>POSIXct. The date and time for starting the search.</dd>


<dt>limit_days</dt>
<dd>Numeric. The number of days to search forward from
<code>start_time</code>. Recommended range: 1 to 10 days.</dd>

</dl>

astro_search_sun_longitude: Search for Sun longitude

Description

Usage

Value

Arguments

Details

Examples