equatorialToLocalHorizontal: Convert Equatorial Coordinate to Local Horizontal Coordinate

In oce: Analysis of Oceanographic Data

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.

See Also

Other things related to astronomy: angle2hms(), eclipticalToEquatorial(), julianCenturyAnomaly(), julianDay(), moonAngle(), siderealTime(), sunAngle(), sunDeclinationRightAscension()

oce documentation built on Sept. 11, 2024, 7:09 p.m.