libnova  v 0.16.0


void ln_get_earth_helio_coords (double JD, struct ln_helio_posn *position)
 Calculate Earth's heliocentric coordinates. More...
double ln_get_earth_solar_dist (double JD)
 Calculate the distance between Earth and the Sun. More...
void ln_get_earth_rect_helio (double JD, struct ln_rect_posn *position)
 Calculate the Earths rectangular heliocentric coordinates. More...
void ln_get_earth_centre_dist (float height, double latitude, double *p_sin_o, double *p_cos_o)
 Calculate Earth globe centre distance. More...

Detailed Description

Functions relating to the planet Earth.

All angles are expressed in degrees.

Function Documentation

void ln_get_earth_centre_dist ( float  height,
double  latitude,
double *  p_sin_o,
double *  p_cos_o 

Calculate Earth globe centre distance.

heightHeight above sea level in metres.
latitudelatitude in degrees.
p_sin_oPointer to hold p_sin_o
p_cos_oPointer to hold p_cos_o

Calculate the quantities "p sin o" and "p cos o" needed in calculations for diurnal parallaxes, eclipses and occultations given the observers height in metres above sea level and there latitude in degrees.

References ln_deg_to_rad().

void ln_get_earth_helio_coords ( double  JD,
struct ln_helio_posn position 

Calculate Earth's heliocentric coordinates.

JDJulian day
positionPointer to store heliocentric position

Calculate Earths heliocentric (referred to the centre of the Sun) coordinates for given julian day. Longitude and Latitude are in degrees, whilst radius vector is in AU.

References ln_helio_posn::B, ln_helio_posn::L, ln_rad_to_deg(), ln_range_degrees(), ln_vsop87_to_fk5(), and ln_helio_posn::R.

Referenced by ln_get_earth_rect_helio(), ln_get_earth_solar_dist(), ln_get_ell_geo_rect_posn(), ln_get_heliocentric_time_diff(), ln_get_hyp_geo_rect_posn(), ln_get_jupiter_earth_dist(), ln_get_mars_earth_dist(), ln_get_mercury_earth_dist(), ln_get_neptune_earth_dist(), ln_get_par_geo_rect_posn(), ln_get_pluto_earth_dist(), ln_get_saturn_earth_dist(), ln_get_solar_geo_coords(), ln_get_solar_geom_coords(), ln_get_uranus_earth_dist(), and ln_get_venus_earth_dist().

void ln_get_earth_rect_helio ( double  JD,
struct ln_rect_posn position 

Calculate the Earths rectangular heliocentric coordinates.

JDJulian day.
positionpointer to return position

Calculate the Earths rectangular heliocentric coordinates for the given Julian day. Coordinates are in AU.

References ln_get_earth_helio_coords(), and ln_get_rect_from_helio().

void ln_get_earth_solar_dist ( double  JD)