R: Convert Equatorial Coordinate to Local Horizontal Coordinate

equatorialToLocalHorizontal {oce}

R Documentation

Convert Equatorial Coordinate to Local Horizontal Coordinate

Description

Convert from equatorial coordinates to local horizontal coordinates, i.e. azimuth and altitude. The method is taken from equations 8.5 and 8.6 of reference 1, or, equivalently, from equations 12.5 and 12.6 of reference 2.

Usage

equatorialToLocalHorizontal(
  rightAscension,
  declination,
  t,
  longitude,
  latitude
)

Arguments

`rightAscension`	right ascension, e.g. calculated with `eclipticalToEquatorial()`.
`declination`	declination, e.g. calculated with `eclipticalToEquatorial()`.
`t`	time of observation.
`longitude`	longitude of observation, positive in eastern hemisphere.
`latitude`	latitude of observation, positive in northern hemisphere.

Value

A data frame containing columns altitude (angle above horizon, in degrees) and azimuth (angle anticlockwise from south, in degrees).

Author(s)

Dan Kelley, based on formulae in references 1 and 2.

References

Meeus, Jean. Astronomical Formulas for Calculators. Second Edition. Richmond, Virginia, USA: Willmann-Bell, 1982.
Meeus, Jean. Astronomical Algorithms. Second Edition. Richmond, Virginia, USA: Willmann-Bell, 1991.