lat               212 ext/date/lib/astro.c int timelib_astro_rise_set_altitude(timelib_time *t_loc, double lon, double lat, double altit, int upper_limb, double *h_rise, double *h_set, timelib_sll *ts_rise, timelib_sll *ts_set, timelib_sll *ts_transit)
lat               266 ext/date/lib/astro.c 		cost = (sind(altit) - sind(lat) * sind(sdec)) / (cosd(lat) * cosd(sdec));
lat                29 ext/date/lib/astro.h #define day_length(year,month,day,lon,lat)  \
lat                30 ext/date/lib/astro.h         __daylen__( year, month, day, lon, lat, -35.0/60.0, 1 )
lat                35 ext/date/lib/astro.h #define day_civil_twilight_length(year,month,day,lon,lat)  \
lat                36 ext/date/lib/astro.h         __daylen__( year, month, day, lon, lat, -6.0, 0 )
lat                41 ext/date/lib/astro.h #define day_nautical_twilight_length(year,month,day,lon,lat)  \
lat                42 ext/date/lib/astro.h         __daylen__( year, month, day, lon, lat, -12.0, 0 )
lat                47 ext/date/lib/astro.h #define day_astronomical_twilight_length(year,month,day,lon,lat)  \
lat                48 ext/date/lib/astro.h         __daylen__( year, month, day, lon, lat, -18.0, 0 )
lat                55 ext/date/lib/astro.h #define timelib_astro_sun_rise_set(ts,lon,lat,hrise,hset,rise,set)  \
lat                56 ext/date/lib/astro.h         timelib_astro_rise_set_altitude( ts, lon, lat, -35.0/60.0, 1, hrise, hset, rise, set )
lat                61 ext/date/lib/astro.h #define civil_twilight(ts,lon,lat,start,end)  \
lat                62 ext/date/lib/astro.h         timelib_astro_rise_set_altitude( ts, lon, lat, -6.0, 0, start, end )
lat                67 ext/date/lib/astro.h #define nautical_twilight(ts,lon,lat,start,end)  \
lat                68 ext/date/lib/astro.h         timelib_astro_rise_set_altitude( ts, lon, lat, -12.0, 0, start, end )
lat                73 ext/date/lib/astro.h #define astronomical_twilight(ts,lon,lat,start,end)  \
lat                74 ext/date/lib/astro.h         timelib_astro_rise_set_altitude( ts, lon, lat, -18.0, 0, start, end )
lat               157 ext/date/lib/timelib.h int timelib_astro_rise_set_altitude(timelib_time *time, double lon, double lat, double altit, int upper_limb, double *h_rise, double *h_set, timelib_sll *ts_rise, timelib_sll *ts_set, timelib_sll *ts_transit);