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.

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).

References

  1. Meeus, Jean, 1982. Astronomical formulae for Calculators. Willmann-Bell. Richmond VA, USA. 201 pages.

  2. Meeus, Jean, 1991. Astronomical algorithms. Willmann-Bell, Richmond VA, USA. 429 pages.

See also