swexcel

Full native API interfaces

Generated from reviewed contracts and the pinned header. SW_SWE_* are worksheet functions. SW_CMD_* are VBA commands; the current-file query is VBA-only in intended use. Pass input vectors as a row/column range or VBA array. Every worksheet function accepts optional options (a two-column key/value array) and detail (TRUE for labeled diagnostics). Configuration commands affect direct native VBA callers; worksheet calls reapply their explicit options.

Units and error conventions follow the upstream programming manual.

Functions

SW_SWE_AZALT

Native: void swe_azalt(double tjd_ut, int32 calc_flag, double *geopos, double atpress, double attemp, double *xin, double *xaz);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
calc_flag	in	1	coordinate/refraction mode code
geopos	in	3	degrees east; degrees north; metres above sea level
atpress	in	1	hPa (0 estimates pressure)
attemp	in	1	degrees Celsius
xin	in	3	coordinates selected by calc_flag, degrees; optional radius
xaz	out	3	azimuth from south toward west; true altitude; apparent altitude, degrees

Output xaz indices:

• 0: azimuth south through west degrees
• 1: true altitude degrees
• 2: apparent altitude degrees

Example inputs in parameter order: [2451545.0, 0, [13.405, 52.52, 34.0], 1013.25, 15.0, [280.0, 1.0, 1.0]].

SW_SWE_AZALT_REV

Native: void swe_azalt_rev(double tjd_ut, int32 calc_flag, double *geopos, double *xin, double *xout);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
calc_flag	in	1	coordinate/refraction mode code
geopos	in	3	degrees east; degrees north; metres above sea level
xin	in	2	coordinates selected by calc_flag, degrees; optional radius
xout	out	2	longitude/right ascension; latitude/declination, degrees

Example inputs in parameter order: [2451545.0, 0, [13.405, 52.52, 34.0], [90.0, 15.0]].

SW_SWE_CALC

Native: int32 swe_calc(double tjd, int ipl, int32 iflag, double *xx, char *serr);

Family: Positions. Return handling: flags.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd	in	1	Julian day TT or explicitly named input time scale
ipl	in	1	Swiss body ID
iflag	in	1	Swiss flag bit mask
xx	out	6	coordinate units selected by flags: degrees/radians or AU, followed by per-day speeds
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 0, 258].

SW_SWE_CALC_PCTR

Native: int32 swe_calc_pctr(double tjd, int32 ipl, int32 iplctr, int32 iflag, double *xxret, char *serr);

Family: Positions. Return handling: flags.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd	in	1	Julian day TT or explicitly named input time scale
ipl	in	1	Swiss body ID
iplctr	in	1	Swiss centre body ID
iflag	in	1	Swiss flag bit mask
xxret	out	6	coordinate units selected by flags: degrees/radians or AU, followed by per-day speeds
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 0, 4, 258].

SW_SWE_CALC_UT

Native: int32 swe_calc_ut(double tjd_ut, int32 ipl, int32 iflag, double *xx, char *serr);

Family: Positions. Return handling: flags.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
ipl	in	1	Swiss body ID
iflag	in	1	Swiss flag bit mask
xx	out	6	coordinate units selected by flags: degrees/radians or AU, followed by per-day speeds
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 0, 258].

SW_CMD_CLOSE

Native: void swe_close(void);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

| Argument | Direction | Capacity | Units | | — | — | —: | — |

Example inputs in parameter order: [].

SW_SWE_COTRANS

Native: void swe_cotrans(double *xpo, double *xpn, double eps);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
xpo	in	3	longitude/latitude degrees; radius; optional matching daily speeds
xpn	out	3	longitude/latitude degrees; radius; optional matching daily speeds
eps	in	1	degrees

Example inputs in parameter order: [[280.0, 1.0, 1.0], 23.4392911].

SW_SWE_COTRANS_SP

Native: void swe_cotrans_sp(double *xpo, double *xpn, double eps);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
xpo	in	6	longitude/latitude degrees; radius; optional matching daily speeds
xpn	out	6	longitude/latitude degrees; radius; optional matching daily speeds
eps	in	1	degrees

Example inputs in parameter order: [[280.0, 1.0, 1.0, 1.0, 0.0, 0.0], 23.4392911].

SW_SWE_CS2DEGSTR

Native: char * swe_cs2degstr(CSEC t, char *a);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
t	in	1	centiseconds (1/360000 degree)
a	out	256	formatted text

Example inputs in parameter order: [1234567].

SW_SWE_CS2LONLATSTR

Native: char * swe_cs2lonlatstr(CSEC t, char pchar, char mchar, char *s);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
t	in	1	centiseconds (1/360000 degree)
pchar	in	1	positive hemisphere character
mchar	in	1	negative hemisphere character
s	out	256	formatted text

Example inputs in parameter order: [1234567, "N", "S"].

SW_SWE_CS2TIMESTR

Native: char * swe_cs2timestr(CSEC t, int sep, AS_BOOL suppressZero, char *a);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
t	in	1	centiseconds (1/360000 degree)
sep	in	1	separator character code
suppressZero	in	1	C boolean 0 or 1
a	out	256	formatted text

Example inputs in parameter order: [1234567, 58, 0].

SW_SWE_CSNORM

Native: centisec swe_csnorm(centisec p);

Family: Utilities. Return handling: signed.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
p	in	1	centiseconds (1/360000 degree)

Example inputs in parameter order: [-360000].

SW_SWE_CSROUNDSEC

Native: centisec swe_csroundsec(centisec x);

Family: Utilities. Return handling: signed.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
x	in	1	centiseconds (1/360000 degree)

Example inputs in parameter order: [1234567].

SW_SWE_D2L

Native: int32 swe_d2l(double x);

Family: Utilities. Return handling: signed.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
x	in	1	degrees

Example inputs in parameter order: [12.345].

SW_SWE_DATE_CONVERSION

Native: int swe_date_conversion(int y, int m, int d, double utime, char c, double *tjd);

Family: Time. Return handling: status.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
y	in	1	astronomical year
m	in	1	month 1..12
d	in	1	day of month
utime	in	1	decimal hours
c	in	1	g Gregorian or j Julian
tjd	out	1	Julian day TT or explicitly named input time scale

Example inputs in parameter order: [2000, 1, 1, 12.0, "g"].

SW_SWE_DAY_OF_WEEK

Native: int swe_day_of_week(double jd);

Family: Time. Return handling: signed.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
jd	in	1	Julian day TT or explicitly named input time scale

Example inputs in parameter order: [2451545.0].

SW_SWE_DEG_MIDP

Native: double swe_deg_midp(double x1, double x0);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
x1	in	1	degrees
x0	in	1	degrees

Example inputs in parameter order: [350.0, 10.0].

SW_SWE_DEGNORM

Native: double swe_degnorm(double x);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
x	in	1	degrees

Example inputs in parameter order: [12.345].

SW_SWE_DELTAT

Native: double swe_deltat(double tjd);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd	in	1	Julian day TT or explicitly named input time scale

Example inputs in parameter order: [2451545.0].

SW_SWE_DELTAT_EX

Native: double swe_deltat_ex(double tjd, int32 iflag, char *serr);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd	in	1	Julian day TT or explicitly named input time scale
iflag	in	1	Swiss flag bit mask
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 258].

SW_SWE_DIFCS2N

Native: centisec swe_difcs2n(centisec p1, centisec p2);

Family: Utilities. Return handling: signed.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
p1	in	1	centiseconds (1/360000 degree)
p2	in	1	centiseconds (1/360000 degree)

Example inputs in parameter order: [129600000, 360000].

SW_SWE_DIFCSN

Native: centisec swe_difcsn(centisec p1, centisec p2);

Family: Utilities. Return handling: signed.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
p1	in	1	centiseconds (1/360000 degree)
p2	in	1	centiseconds (1/360000 degree)

Example inputs in parameter order: [129600000, 360000].

SW_SWE_DIFDEG2N

Native: double swe_difdeg2n(double p1, double p2);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
p1	in	1	degrees
p2	in	1	degrees

Example inputs in parameter order: [350.0, 10.0].

SW_SWE_DIFDEGN

Native: double swe_difdegn(double p1, double p2);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
p1	in	1	degrees
p2	in	1	degrees

Example inputs in parameter order: [350.0, 10.0].

SW_SWE_DIFRAD2N

Native: double swe_difrad2n(double p1, double p2);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
p1	in	1	radians
p2	in	1	radians

Example inputs in parameter order: [3.0, -3.0].

SW_SWE_FIXSTAR

Native: int32 swe_fixstar(char *star, double tjd, int32 iflag, double *xx, char *serr);

Family: Stars. Return handling: flags.

Data: sefstars.txt; selected planetary ephemeris for apparent corrections.

Argument	Direction	Capacity	Units
star	inout	256	star name or catalog index; canonical name is returned
tjd	in	1	Julian day TT or explicitly named input time scale
iflag	in	1	Swiss flag bit mask
xx	out	6	coordinate units selected by flags: degrees/radians or AU, followed by per-day speeds
serr	out	256	diagnostic text

Example inputs in parameter order: ["Spica", 2451545.0, 258].

SW_SWE_FIXSTAR2

Native: int32 swe_fixstar2(char *star, double tjd, int32 iflag, double *xx, char *serr);

Family: Stars. Return handling: flags.

Data: sefstars.txt; selected planetary ephemeris for apparent corrections.

Argument	Direction	Capacity	Units
star	inout	256	star name or catalog index; canonical name is returned
tjd	in	1	Julian day TT or explicitly named input time scale
iflag	in	1	Swiss flag bit mask
xx	out	6	coordinate units selected by flags: degrees/radians or AU, followed by per-day speeds
serr	out	256	diagnostic text

Example inputs in parameter order: ["Spica", 2451545.0, 258].

SW_SWE_FIXSTAR2_MAG

Native: int32 swe_fixstar2_mag(char *star, double *mag, char *serr);

Family: Stars. Return handling: status.

Data: sefstars.txt; selected planetary ephemeris for apparent corrections.

Argument	Direction	Capacity	Units
star	inout	256	star name or catalog index; canonical name is returned
mag	out	1	astronomical magnitude
serr	out	256	diagnostic text

Example inputs in parameter order: ["Spica"].

SW_SWE_FIXSTAR2_UT

Native: int32 swe_fixstar2_ut(char *star, double tjd_ut, int32 iflag, double *xx, char *serr);

Family: Stars. Return handling: flags.

Data: sefstars.txt; selected planetary ephemeris for apparent corrections.

Argument	Direction	Capacity	Units
star	inout	256	star name or catalog index; canonical name is returned
tjd_ut	in	1	Julian day UT1
iflag	in	1	Swiss flag bit mask
xx	out	6	coordinate units selected by flags: degrees/radians or AU, followed by per-day speeds
serr	out	256	diagnostic text

Example inputs in parameter order: ["Spica", 2451545.0, 258].

SW_SWE_FIXSTAR_MAG

Native: int32 swe_fixstar_mag(char *star, double *mag, char *serr);

Family: Stars. Return handling: status.

Data: sefstars.txt; selected planetary ephemeris for apparent corrections.

Argument	Direction	Capacity	Units
star	inout	256	star name or catalog index; canonical name is returned
mag	out	1	astronomical magnitude
serr	out	256	diagnostic text

Example inputs in parameter order: ["Spica"].

SW_SWE_FIXSTAR_UT

Native: int32 swe_fixstar_ut(char *star, double tjd_ut, int32 iflag, double *xx, char *serr);

Family: Stars. Return handling: flags.

Data: sefstars.txt; selected planetary ephemeris for apparent corrections.

Argument	Direction	Capacity	Units
star	inout	256	star name or catalog index; canonical name is returned
tjd_ut	in	1	Julian day UT1
iflag	in	1	Swiss flag bit mask
xx	out	6	coordinate units selected by flags: degrees/radians or AU, followed by per-day speeds
serr	out	256	diagnostic text

Example inputs in parameter order: ["Spica", 2451545.0, 258].

SW_SWE_GAUQUELIN_SECTOR

Native: int32 swe_gauquelin_sector(double t_ut, int32 ipl, char *starname, int32 iflag, int32 imeth, double *geopos, double atpress, double attemp, double *dgsect, char *serr);

Family: Houses. Return handling: status.

Data: Date-based houses use obliquity/nutation; ARMC houses need no binary data; Gauquelin body calculations need the selected body files.

Argument	Direction	Capacity	Units
t_ut	in	1	Julian day UT1
ipl	in	1	Swiss body ID
starname	in	256	star name, or empty to use ipl
iflag	in	1	Swiss flag bit mask
imeth	in	1	Gauquelin method 0..5
geopos	in	3	degrees east; degrees north; metres above sea level
atpress	in	1	hPa (0 estimates pressure)
attemp	in	1	degrees Celsius
dgsect	out	1	Gauquelin sector 1..36
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 0, "", 258, 0, [13.405, 52.52, 34.0], 1013.25, 15.0].

SW_SWE_GET_ASTRO_MODELS

Native: void swe_get_astro_models(char *samod, char *sdet, int32 iflag);

Family: Utilities. Return handling: value. Upstream experimental.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
samod	in	256	experimental astronomical model/version specification
sdet	out	16384	experimental model-description text
iflag	in	1	Swiss flag bit mask

Example inputs in parameter order: ["0,0,0,0,0,0,0,0", 258].

SW_SWE_GET_AYANAMSA

Native: double swe_get_ayanamsa(double tjd_et);

Family: Positions. Return handling: value.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_et	in	1	Julian day TT or explicitly named input time scale

Example inputs in parameter order: [2451545.0].

SW_SWE_GET_AYANAMSA_EX

Native: int32 swe_get_ayanamsa_ex(double tjd_et, int32 iflag, double *daya, char *serr);

Family: Positions. Return handling: flags.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_et	in	1	Julian day TT or explicitly named input time scale
iflag	in	1	Swiss flag bit mask
daya	out	1	degrees
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 258].

SW_SWE_GET_AYANAMSA_EX_UT

Native: int32 swe_get_ayanamsa_ex_ut(double tjd_ut, int32 iflag, double *daya, char *serr);

Family: Positions. Return handling: flags.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
iflag	in	1	Swiss flag bit mask
daya	out	1	degrees
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 258].

SW_SWE_GET_AYANAMSA_NAME

Native: const char * swe_get_ayanamsa_name(int32 isidmode);

Family: Positions. Return handling: value.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
isidmode	in	1	built-in sidereal ID 0..46

Example inputs in parameter order: [1].

SW_SWE_GET_AYANAMSA_UT

Native: double swe_get_ayanamsa_ut(double tjd_ut);

Family: Positions. Return handling: value.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1

Example inputs in parameter order: [2451545.0].

SW_CMD_GET_CURRENT_FILE_DATA

Native: const char * swe_get_current_file_data(int ifno, double *tfstart, double *tfend, int *denum);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
ifno	in	1	file slot 0..4
tfstart	out	1	Julian day TT
tfend	out	1	Julian day TT
denum	out	1	JPL DE number

Example inputs in parameter order: [0].

SW_SWE_GET_LIBRARY_PATH

Native: char * swe_get_library_path(char *);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
arg1	out	256	NUL-terminated string

Example inputs in parameter order: [].

SW_SWE_GET_ORBITAL_ELEMENTS

Native: int32 swe_get_orbital_elements(double tjd_et, int32 ipl, int32 iflag, double *dret, char *serr);

Family: Positions. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_et	in	1	Julian day TT or explicitly named input time scale
ipl	in	1	Swiss body ID
iflag	in	1	Swiss flag bit mask
dret	out	50	a AU; e; inclination/node/periapsis/anomalies/longitudes degrees; daily motion degrees/day; sidereal/tropical periods years; synodic period days; perihelion epoch JD TT; perihelion/aphelion AU
serr	out	256	diagnostic text

Output dret indices:

• 0: semimajor axis AU
• 1: eccentricity
• 2: inclination degrees
• 3: ascending node degrees
• 4: argument of perihelion degrees
• 5: longitude of perihelion degrees
• 6: mean anomaly degrees
• 7: true anomaly degrees
• 8: eccentric anomaly degrees
• 9: mean longitude degrees
• 10: sidereal period tropical years
• 11: mean daily motion degrees/day
• 12: tropical period years
• 13: synodic period days
• 14: perihelion epoch JD TT
• 15: perihelion distance AU
• 16: aphelion distance AU

Example inputs in parameter order: [2451545.0, 4, 258].

SW_SWE_GET_PLANET_NAME

Native: char * swe_get_planet_name(int ipl, char *spname);

Family: Positions. Return handling: value.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
ipl	in	1	Swiss body ID
spname	out	256	body name

Example inputs in parameter order: [0].

SW_SWE_GET_TID_ACC

Native: double swe_get_tid_acc(void);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

| Argument | Direction | Capacity | Units | | — | — | —: | — |

Example inputs in parameter order: [].

SW_SWE_HELIACAL_ANGLE

Native: int32 swe_heliacal_angle(double tjdut, double *dgeo, double *datm, double *dobs, int32 helflag, double mag, double azi_obj, double azi_sun, double azi_moon, double alt_moon, double *dret, char *serr);

Family: Heliacal. Return handling: status. Upstream experimental.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjdut	in	1	Julian day UT1
dgeo	in	3	degrees east; degrees north; metres above sea level
datm	inout	4	hPa; Celsius; relative humidity percent; visibility km or extinction coefficient
dobs	inout	6	age years; Snellen ratio; binocular flag; magnification; aperture mm; transmission fraction
helflag	in	1	heliacal flag bit mask
mag	in	1	astronomical magnitude
azi_obj	in	1	azimuth degrees
azi_sun	in	1	azimuth degrees
azi_moon	in	1	azimuth degrees
alt_moon	in	1	altitude degrees
dret	out	3	optimum object altitude; minimum arcus visionis; solar altitude, degrees
serr	out	256	diagnostic text

Output dret indices:

• 0: optimum object altitude degrees
• 1: minimum arcus visionis degrees
• 2: Sun altitude degrees

Example inputs in parameter order: [2451545.0, [13.405, 52.52, 34.0], [1013.25, 15.0, 40.0, 0.0], [36.0, 1.0, 0.0, 1.0, 0.0, 0.0], 0, 0.0, 90.0, 100.0, 110.0, -10.0].

SW_SWE_HELIACAL_PHENO_UT

Native: int32 swe_heliacal_pheno_ut(double tjd_ut, double *geopos, double *datm, double *dobs, char *ObjectName, int32 TypeEvent, int32 helflag, double *darr, char *serr);

Family: Heliacal. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
geopos	in	3	degrees east; degrees north; metres above sea level
datm	inout	4	hPa; Celsius; relative humidity percent; visibility km or extinction coefficient
dobs	inout	6	age years; Snellen ratio; binocular flag; magnification; aperture mm; transmission fraction
ObjectName	in	256	planet or fixed-star name
TypeEvent	in	1	heliacal event type 1..6
helflag	in	1	heliacal flag bit mask
darr	out	50	indexed heliacal circumstances: degrees, days, magnitudes and dimensionless visibility measures; see field reference
serr	out	256	diagnostic text

Output darr indices:

• 0: object true altitude degrees
• 1: object apparent altitude degrees
• 2: geocentric altitude degrees
• 3: object azimuth degrees
• 4: Sun altitude degrees
• 5: Sun azimuth degrees
• 6: topocentric arcus visionis degrees
• 7: geocentric arcus visionis degrees
• 8: azimuth difference degrees
• 9: longitude difference degrees
• 10: extinction coefficient
• 11: minimum arcus visionis degrees
• 12: first visibility JD UT1
• 13: optimum visibility JD UT1
• 14: last visibility JD UT1
• 15: Yallop best time JD UT1
• 16: crescent width degrees
• 17: Yallop q
• 18: Yallop criterion
• 19: parallax degrees
• 20: magnitude
• 21: object rise/set JD UT1
• 22: Sun rise/set JD UT1
• 23: lag days
• 24: visibility duration days
• 25: crescent length degrees
• 26: elongation degrees
• 27: illuminated percent

Example inputs in parameter order: [2451545.0, [13.405, 52.52, 34.0], [1013.25, 15.0, 40.0, 0.0], [36.0, 1.0, 0.0, 1.0, 0.0, 0.0], "venus", 1, 0].

SW_SWE_HELIACAL_UT

Native: int32 swe_heliacal_ut(double tjdstart_ut, double *geopos, double *datm, double *dobs, char *ObjectName, int32 TypeEvent, int32 iflag, double *dret, char *serr);

Family: Heliacal. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjdstart_ut	in	1	Julian day UT1
geopos	in	3	degrees east; degrees north; metres above sea level
datm	inout	4	hPa; Celsius; relative humidity percent; visibility km or extinction coefficient
dobs	inout	6	age years; Snellen ratio; binocular flag; magnification; aperture mm; transmission fraction
ObjectName	in	256	planet or fixed-star name
TypeEvent	in	1	heliacal event type 1..6
iflag	in	1	Swiss flag bit mask
dret	out	10	Julian day UT1 beginning/optimum/end; unavailable dates are zero
serr	out	256	diagnostic text

Output dret indices:

• 0: first visibility JD UT1
• 1: optimum visibility JD UT1
• 2: last visibility JD UT1

Example inputs in parameter order: [2451545.0, [13.405, 52.52, 34.0], [1013.25, 15.0, 40.0, 0.0], [36.0, 1.0, 0.0, 1.0, 0.0, 0.0], "venus", 1, 258].

SW_SWE_HELIO_CROSS

Native: int32 swe_helio_cross(int32 ipl, double x2cross, double jd_et, int32 iflag, int32 dir, double *jd_cross, char *serr);

Family: Events. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
ipl	in	1	Swiss body ID
x2cross	in	1	target ecliptic longitude, degrees
jd_et	in	1	Julian day TT or explicitly named input time scale
iflag	in	1	Swiss flag bit mask
dir	in	1	positive forward or negative backward
jd_cross	out	1	Julian day TT or explicitly named input time scale
serr	out	256	diagnostic text

Example inputs in parameter order: [4, 0.0, 2451545.0, 258, 1].

SW_SWE_HELIO_CROSS_UT

Native: int32 swe_helio_cross_ut(int32 ipl, double x2cross, double jd_ut, int32 iflag, int32 dir, double *jd_cross, char *serr);

Family: Events. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
ipl	in	1	Swiss body ID
x2cross	in	1	target ecliptic longitude, degrees
jd_ut	in	1	Julian day UT1
iflag	in	1	Swiss flag bit mask
dir	in	1	positive forward or negative backward
jd_cross	out	1	Julian day UT1
serr	out	256	diagnostic text

Example inputs in parameter order: [4, 0.0, 2451545.0, 258, 1].

SW_SWE_HOUSE_NAME

Native: const char * swe_house_name(int hsys);

Family: Houses. Return handling: value.

Data: Date-based houses use obliquity/nutation; ARMC houses need no binary data; Gauquelin body calculations need the selected body files.

Argument	Direction	Capacity	Units
hsys	in	1	one-character house system

Example inputs in parameter order: ["P"].

SW_SWE_HOUSE_POS

Native: double swe_house_pos(double armc, double geolat, double eps, int hsys, double *xpin, char *serr);

Family: Houses. Return handling: house_position.

Data: Date-based houses use obliquity/nutation; ARMC houses need no binary data; Gauquelin body calculations need the selected body files.

Argument	Direction	Capacity	Units
armc	in	1	degrees
geolat	in	1	degrees north
eps	in	1	degrees
hsys	in	1	one-character house system
xpin	in	2	ecliptic longitude and latitude, degrees
serr	out	256	diagnostic text

Example inputs in parameter order: [280.0, 52.52, 23.4392911, "P", [280.0, 1.0]].

SW_SWE_HOUSES

Native: int swe_houses(double tjd_ut, double geolat, double geolon, int hsys, double *cusps, double *ascmc);

Family: Houses. Return handling: status.

Data: Date-based houses use obliquity/nutation; ARMC houses need no binary data; Gauquelin body calculations need the selected body files.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
geolat	in	1	degrees north
geolon	in	1	degrees east
hsys	in	1	one-character house system
cusps	out	37	degrees (radians with SEFLG_RADIANS); index 1..12 or 1..36 for G
ascmc	out	10	degrees (radians with SEFLG_RADIANS)

Output ascmc indices:

• 0: Ascendant; degrees (radians with SEFLG_RADIANS)
• 1: Midheaven; degrees (radians with SEFLG_RADIANS)
• 2: ARMC; degrees (radians with SEFLG_RADIANS)
• 3: Vertex; degrees (radians with SEFLG_RADIANS)
• 4: equatorial Ascendant; degrees (radians with SEFLG_RADIANS)
• 5: Koch co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 6: Munkasey co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 7: polar Ascendant; degrees (radians with SEFLG_RADIANS)

Example inputs in parameter order: [2451545.0, 52.52, 13.405, "P"].

SW_SWE_HOUSES_ARMC

Native: int swe_houses_armc(double armc, double geolat, double eps, int hsys, double *cusps, double *ascmc);

Family: Houses. Return handling: status.

Data: Date-based houses use obliquity/nutation; ARMC houses need no binary data; Gauquelin body calculations need the selected body files.

Argument	Direction	Capacity	Units
armc	in	1	degrees
geolat	in	1	degrees north
eps	in	1	degrees
hsys	in	1	one-character house system
cusps	out	37	degrees (radians with SEFLG_RADIANS); index 1..12 or 1..36 for G
ascmc	inout	10	degrees (radians with SEFLG_RADIANS)

Output ascmc indices:

• 0: Ascendant; degrees (radians with SEFLG_RADIANS)
• 1: Midheaven; degrees (radians with SEFLG_RADIANS)
• 2: ARMC; degrees (radians with SEFLG_RADIANS)
• 3: Vertex; degrees (radians with SEFLG_RADIANS)
• 4: equatorial Ascendant; degrees (radians with SEFLG_RADIANS)
• 5: Koch co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 6: Munkasey co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 7: polar Ascendant; degrees (radians with SEFLG_RADIANS)
• 8: reserved; degrees (radians with SEFLG_RADIANS)
• 9: Sun declination (Sunshine ARMC input); degrees (radians with SEFLG_RADIANS)

Example inputs in parameter order: [280.0, 52.52, 23.4392911, "P", [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]].

SW_SWE_HOUSES_ARMC_EX2

Native: int swe_houses_armc_ex2(double armc, double geolat, double eps, int hsys, double *cusps, double *ascmc, double *cusp_speed, double *ascmc_speed, char *serr);

Family: Houses. Return handling: status.

Data: Date-based houses use obliquity/nutation; ARMC houses need no binary data; Gauquelin body calculations need the selected body files.

Argument	Direction	Capacity	Units
armc	in	1	degrees
geolat	in	1	degrees north
eps	in	1	degrees
hsys	in	1	one-character house system
cusps	out	37	degrees (radians with SEFLG_RADIANS); index 1..12 or 1..36 for G
ascmc	inout	10	degrees (radians with SEFLG_RADIANS)
cusp_speed	out	37	degrees/day (radians/day with SEFLG_RADIANS)
ascmc_speed	out	10	degrees/day (radians/day with SEFLG_RADIANS)
serr	out	256	diagnostic text

Output ascmc indices:

• 0: Ascendant; degrees (radians with SEFLG_RADIANS)
• 1: Midheaven; degrees (radians with SEFLG_RADIANS)
• 2: ARMC; degrees (radians with SEFLG_RADIANS)
• 3: Vertex; degrees (radians with SEFLG_RADIANS)
• 4: equatorial Ascendant; degrees (radians with SEFLG_RADIANS)
• 5: Koch co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 6: Munkasey co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 7: polar Ascendant; degrees (radians with SEFLG_RADIANS)
• 8: reserved; degrees (radians with SEFLG_RADIANS)
• 9: Sun declination (Sunshine ARMC input); degrees (radians with SEFLG_RADIANS)

Output ascmc_speed indices:

• 0: Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 1: Midheaven daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 2: ARMC daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 3: Vertex daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 4: equatorial Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 5: Koch co-Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 6: Munkasey co-Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 7: polar Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)

Example inputs in parameter order: [280.0, 52.52, 23.4392911, "P", [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]].

SW_SWE_HOUSES_EX

Native: int swe_houses_ex(double tjd_ut, int32 iflag, double geolat, double geolon, int hsys, double *cusps, double *ascmc);

Family: Houses. Return handling: status.

Data: Date-based houses use obliquity/nutation; ARMC houses need no binary data; Gauquelin body calculations need the selected body files.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
iflag	in	1	Swiss flag bit mask
geolat	in	1	degrees north
geolon	in	1	degrees east
hsys	in	1	one-character house system
cusps	out	37	degrees (radians with SEFLG_RADIANS); index 1..12 or 1..36 for G
ascmc	out	10	degrees (radians with SEFLG_RADIANS)

Output ascmc indices:

• 0: Ascendant; degrees (radians with SEFLG_RADIANS)
• 1: Midheaven; degrees (radians with SEFLG_RADIANS)
• 2: ARMC; degrees (radians with SEFLG_RADIANS)
• 3: Vertex; degrees (radians with SEFLG_RADIANS)
• 4: equatorial Ascendant; degrees (radians with SEFLG_RADIANS)
• 5: Koch co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 6: Munkasey co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 7: polar Ascendant; degrees (radians with SEFLG_RADIANS)

Example inputs in parameter order: [2451545.0, 258, 52.52, 13.405, "P"].

SW_SWE_HOUSES_EX2

Native: int swe_houses_ex2(double tjd_ut, int32 iflag, double geolat, double geolon, int hsys, double *cusps, double *ascmc, double *cusp_speed, double *ascmc_speed, char *serr);

Family: Houses. Return handling: status.

Data: Date-based houses use obliquity/nutation; ARMC houses need no binary data; Gauquelin body calculations need the selected body files.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
iflag	in	1	Swiss flag bit mask
geolat	in	1	degrees north
geolon	in	1	degrees east
hsys	in	1	one-character house system
cusps	out	37	degrees (radians with SEFLG_RADIANS); index 1..12 or 1..36 for G
ascmc	out	10	degrees (radians with SEFLG_RADIANS)
cusp_speed	out	37	degrees/day (radians/day with SEFLG_RADIANS)
ascmc_speed	out	10	degrees/day (radians/day with SEFLG_RADIANS)
serr	out	256	diagnostic text

Output ascmc indices:

• 0: Ascendant; degrees (radians with SEFLG_RADIANS)
• 1: Midheaven; degrees (radians with SEFLG_RADIANS)
• 2: ARMC; degrees (radians with SEFLG_RADIANS)
• 3: Vertex; degrees (radians with SEFLG_RADIANS)
• 4: equatorial Ascendant; degrees (radians with SEFLG_RADIANS)
• 5: Koch co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 6: Munkasey co-Ascendant; degrees (radians with SEFLG_RADIANS)
• 7: polar Ascendant; degrees (radians with SEFLG_RADIANS)

Output ascmc_speed indices:

• 0: Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 1: Midheaven daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 2: ARMC daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 3: Vertex daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 4: equatorial Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 5: Koch co-Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 6: Munkasey co-Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)
• 7: polar Ascendant daily speed; degrees/day (radians/day with SEFLG_RADIANS)

Example inputs in parameter order: [2451545.0, 258, 52.52, 13.405, "P"].

SW_SWE_JDET_TO_UTC

Native: void swe_jdet_to_utc(double tjd_et, int32 gregflag, int32 *iyear, int32 *imonth, int32 *iday, int32 *ihour, int32 *imin, double *dsec);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd_et	in	1	Julian day TT or explicitly named input time scale
gregflag	in	1	0 Julian, 1 Gregorian
iyear	out	1	astronomical year
imonth	out	1	month 1..12
iday	out	1	day of month
ihour	out	1	hour 0..23
imin	out	1	minutes
dsec	out	1	seconds, leap second allowed where documented

Example inputs in parameter order: [2451545.0, 1].

SW_SWE_JDUT1_TO_UTC

Native: void swe_jdut1_to_utc(double tjd_ut, int32 gregflag, int32 *iyear, int32 *imonth, int32 *iday, int32 *ihour, int32 *imin, double *dsec);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
gregflag	in	1	0 Julian, 1 Gregorian
iyear	out	1	astronomical year
imonth	out	1	month 1..12
iday	out	1	day of month
ihour	out	1	hour 0..23
imin	out	1	minutes
dsec	out	1	seconds, leap second allowed where documented

Example inputs in parameter order: [2451545.0, 1].

SW_SWE_JULDAY

Native: double swe_julday(int year, int month, int day, double hour, int gregflag);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
year	in	1	astronomical year
month	in	1	month 1..12
day	in	1	day of month
hour	in	1	decimal hours
gregflag	in	1	0 Julian, 1 Gregorian

Example inputs in parameter order: [2000, 1, 1, 12.0, 1].

SW_SWE_LAT_TO_LMT

Native: int32 swe_lat_to_lmt(double tjd_lat, double geolon, double *tjd_lmt, char *serr);

Family: Time. Return handling: status.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd_lat	in	1	Julian day TT or explicitly named input time scale
geolon	in	1	degrees east
tjd_lmt	out	1	Julian day TT or explicitly named input time scale
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 13.405].

SW_SWE_LMT_TO_LAT

Native: int32 swe_lmt_to_lat(double tjd_lmt, double geolon, double *tjd_lat, char *serr);

Family: Time. Return handling: status.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd_lmt	in	1	Julian day TT or explicitly named input time scale
geolon	in	1	degrees east
tjd_lat	out	1	Julian day TT or explicitly named input time scale
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 13.405].

SW_SWE_LUN_ECLIPSE_HOW

Native: int32 swe_lun_eclipse_how(double tjd_ut, int32 ifl, double *geopos, double *attr, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
ifl	in	1	ephemeris flag bit mask
geopos	in	3	degrees east; degrees north; metres above sea level
attr	out	20	indexed event/phenomena attributes; see field reference
serr	out	256	diagnostic text

Output attr indices:

• 0: umbral magnitude
• 1: penumbral magnitude
• 2: reserved
• 3: reserved
• 4: Moon azimuth degrees
• 5: true altitude degrees
• 6: apparent altitude degrees
• 7: opposition distance degrees
• 8: eclipse magnitude
• 9: Saros series
• 10: Saros member

Example inputs in parameter order: [2451545.0, 2, [13.405, 52.52, 34.0]].

SW_SWE_LUN_ECLIPSE_WHEN

Native: int32 swe_lun_eclipse_when(double tjd_start, int32 ifl, int32 ifltype, double *tret, int32 backward, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_start	in	1	Julian day UT1
ifl	in	1	ephemeris flag bit mask
ifltype	in	1	event type bit mask
tret	out	10	Julian day UT1; 0 means unavailable contact
backward	in	1	0 forward, 1 backward; occultation one-try bit 32768
serr	out	256	diagnostic text

Output tret indices:

• 0: maximum JD UT1
• 1: reserved
• 2: partial begins JD UT1
• 3: partial ends JD UT1
• 4: total begins JD UT1
• 5: total ends JD UT1
• 6: penumbral begins JD UT1
• 7: penumbral ends JD UT1
• 8: moonrise JD UT1 (local only)
• 9: moonset JD UT1 (local only)

Example inputs in parameter order: [2451545.0, 2, 0, 0].

SW_SWE_LUN_ECLIPSE_WHEN_LOC

Native: int32 swe_lun_eclipse_when_loc(double tjd_start, int32 ifl, double *geopos, double *tret, double *attr, int32 backward, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_start	in	1	Julian day UT1
ifl	in	1	ephemeris flag bit mask
geopos	in	3	degrees east; degrees north; metres above sea level
tret	out	10	Julian day UT1; 0 means unavailable contact
attr	out	20	indexed event/phenomena attributes; see field reference
backward	in	1	0 forward, 1 backward; occultation one-try bit 32768
serr	out	256	diagnostic text

Output tret indices:

• 0: maximum JD UT1
• 1: reserved
• 2: partial begins JD UT1
• 3: partial ends JD UT1
• 4: total begins JD UT1
• 5: total ends JD UT1
• 6: penumbral begins JD UT1
• 7: penumbral ends JD UT1
• 8: moonrise JD UT1 (local only)
• 9: moonset JD UT1 (local only)

Output attr indices:

• 0: umbral magnitude
• 1: penumbral magnitude
• 2: reserved
• 3: reserved
• 4: Moon azimuth degrees
• 5: true altitude degrees
• 6: apparent altitude degrees
• 7: opposition distance degrees
• 8: eclipse magnitude
• 9: Saros series
• 10: Saros member

Example inputs in parameter order: [2451545.0, 2, [13.405, 52.52, 34.0], 0].

SW_SWE_LUN_OCCULT_WHEN_GLOB

Native: int32 swe_lun_occult_when_glob(double tjd_start, int32 ipl, char *starname, int32 ifl, int32 ifltype, double *tret, int32 backward, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_start	in	1	Julian day UT1
ipl	in	1	Swiss body ID
starname	in	256	star name, or empty to use ipl
ifl	in	1	ephemeris flag bit mask
ifltype	in	1	event type bit mask
tret	out	10	Julian day UT1; 0 means unavailable contact
backward	in	1	0 forward, 1 backward; occultation one-try bit 32768
serr	out	256	diagnostic text

Output tret indices:

• 0: maximum JD UT1
• 1: local apparent noon JD UT1
• 2: eclipse begins JD UT1
• 3: eclipse ends JD UT1
• 4: totality begins JD UT1
• 5: totality ends JD UT1
• 6: centre line begins JD UT1
• 7: centre line ends JD UT1
• 8: reserved unimplemented
• 9: reserved unimplemented

Example inputs in parameter order: [2451545.0, 3, "", 2, 0, 0].

SW_SWE_LUN_OCCULT_WHEN_LOC

Native: int32 swe_lun_occult_when_loc(double tjd_start, int32 ipl, char *starname, int32 ifl, double *geopos, double *tret, double *attr, int32 backward, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_start	in	1	Julian day UT1
ipl	in	1	Swiss body ID
starname	in	256	star name, or empty to use ipl
ifl	in	1	ephemeris flag bit mask
geopos	in	3	degrees east; degrees north; metres above sea level
tret	out	10	Julian day UT1; 0 means unavailable contact
attr	out	20	indexed event/phenomena attributes; see field reference
backward	in	1	0 forward, 1 backward; occultation one-try bit 32768
serr	out	256	diagnostic text

Output tret indices:

• 0: maximum JD UT1
• 1: first contact JD UT1
• 2: second contact JD UT1
• 3: third contact JD UT1
• 4: fourth contact JD UT1
• 5: sunrise JD UT1
• 6: sunset JD UT1
• 7: reserved
• 8: reserved
• 9: reserved

Output attr indices:

• 0: diameter fraction covered
• 1: Moon/object diameter ratio
• 2: disc obscuration fraction
• 3: core shadow diameter km
• 4: azimuth south through west degrees
• 5: true altitude degrees
• 6: apparent altitude degrees
• 7: Moon/object separation degrees
• 8: NASA magnitude
• 9: Saros series (-99999999 unavailable)
• 10: Saros member (-99999999 unavailable)

Example inputs in parameter order: [2451545.0, 3, "", 2, [13.405, 52.52, 34.0], 0].

SW_SWE_LUN_OCCULT_WHERE

Native: int32 swe_lun_occult_where(double tjd, int32 ipl, char *starname, int32 ifl, double *geopos, double *attr, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd	in	1	Julian day UT1
ipl	in	1	Swiss body ID
starname	in	256	star name, or empty to use ipl
ifl	in	1	ephemeris flag bit mask
geopos	out	10	degrees east; degrees north; metres above sea level
attr	out	20	indexed event/phenomena attributes; see field reference
serr	out	256	diagnostic text

Output geopos indices:

• 0: central longitude degrees east
• 1: central latitude degrees north

Output attr indices:

• 0: diameter fraction covered
• 1: Moon/object diameter ratio
• 2: disc obscuration fraction
• 3: core shadow diameter km
• 4: azimuth south through west degrees
• 5: true altitude degrees
• 6: apparent altitude degrees
• 7: Moon/object separation degrees
• 8: NASA magnitude
• 9: Saros series (-99999999 unavailable)
• 10: Saros member (-99999999 unavailable)

Example inputs in parameter order: [2451545.0, 3, "", 2].

SW_SWE_MOONCROSS

Native: double swe_mooncross(double x2cross, double jd_et, int32 flag, char *serr);

Family: Events. Return handling: crossing.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
x2cross	in	1	target ecliptic longitude, degrees
jd_et	in	1	Julian day TT or explicitly named input time scale
flag	in	1	Swiss flag bit mask
serr	out	256	diagnostic text

Example inputs in parameter order: [0.0, 2451545.0, 258].

SW_SWE_MOONCROSS_NODE

Native: double swe_mooncross_node(double jd_et, int32 flag, double *xlon, double *xlat, char *serr);

Family: Events. Return handling: crossing.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
jd_et	in	1	Julian day TT or explicitly named input time scale
flag	in	1	Swiss flag bit mask
xlon	out	1	degrees
xlat	out	1	degrees
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 258].

SW_SWE_MOONCROSS_NODE_UT

Native: double swe_mooncross_node_ut(double jd_ut, int32 flag, double *xlon, double *xlat, char *serr);

Family: Events. Return handling: crossing.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
jd_ut	in	1	Julian day UT1
flag	in	1	Swiss flag bit mask
xlon	out	1	degrees
xlat	out	1	degrees
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 258].

SW_SWE_MOONCROSS_UT

Native: double swe_mooncross_ut(double x2cross, double jd_ut, int32 flag, char *serr);

Family: Events. Return handling: crossing.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
x2cross	in	1	target ecliptic longitude, degrees
jd_ut	in	1	Julian day UT1
flag	in	1	Swiss flag bit mask
serr	out	256	diagnostic text

Example inputs in parameter order: [0.0, 2451545.0, 258].

SW_SWE_NOD_APS

Native: int32 swe_nod_aps(double tjd_et, int32 ipl, int32 iflag, int32 method, double *xnasc, double *xndsc, double *xperi, double *xaphe, char *serr);

Family: Positions. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_et	in	1	Julian day TT or explicitly named input time scale
ipl	in	1	Swiss body ID
iflag	in	1	Swiss flag bit mask
method	in	1	node/apsis method bit mask
xnasc	out	6	ascending node coordinates and speeds, selected by flags
xndsc	out	6	descending node coordinates and speeds, selected by flags
xperi	out	6	periapsis coordinates and speeds, selected by flags
xaphe	out	6	apoapsis/focal-point coordinates and speeds, selected by flags
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 0, 258, 0].

SW_SWE_NOD_APS_UT

Native: int32 swe_nod_aps_ut(double tjd_ut, int32 ipl, int32 iflag, int32 method, double *xnasc, double *xndsc, double *xperi, double *xaphe, char *serr);

Family: Positions. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
ipl	in	1	Swiss body ID
iflag	in	1	Swiss flag bit mask
method	in	1	node/apsis method bit mask
xnasc	out	6	ascending node coordinates and speeds, selected by flags
xndsc	out	6	descending node coordinates and speeds, selected by flags
xperi	out	6	periapsis coordinates and speeds, selected by flags
xaphe	out	6	apoapsis/focal-point coordinates and speeds, selected by flags
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 0, 258, 0].

SW_SWE_ORBIT_MAX_MIN_TRUE_DISTANCE

Native: int32 swe_orbit_max_min_true_distance(double tjd_et, int32 ipl, int32 iflag, double *dmax, double *dmin, double *dtrue, char *serr);

Family: Positions. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_et	in	1	Julian day TT or explicitly named input time scale
ipl	in	1	Swiss body ID
iflag	in	1	Swiss flag bit mask
dmax	out	1	AU
dmin	out	1	AU
dtrue	out	1	AU
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 0, 258].

SW_SWE_PHENO

Native: int32 swe_pheno(double tjd, int32 ipl, int32 iflag, double *attr, char *serr);

Family: Positions. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd	in	1	Julian day TT or explicitly named input time scale
ipl	in	1	Swiss body ID
iflag	in	1	Swiss flag bit mask
attr	out	20	indexed event/phenomena attributes; see field reference
serr	out	256	diagnostic text

Output attr indices:

• 0: phase angle degrees
• 1: illuminated fraction
• 2: elongation degrees
• 3: apparent diameter degrees
• 4: apparent magnitude
• 5: horizontal parallax degrees (Moon)

Example inputs in parameter order: [2451545.0, 0, 258].

SW_SWE_PHENO_UT

Native: int32 swe_pheno_ut(double tjd_ut, int32 ipl, int32 iflag, double *attr, char *serr);

Family: Positions. Return handling: status.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
ipl	in	1	Swiss body ID
iflag	in	1	Swiss flag bit mask
attr	out	20	indexed event/phenomena attributes; see field reference
serr	out	256	diagnostic text

Output attr indices:

• 0: phase angle degrees
• 1: illuminated fraction
• 2: elongation degrees
• 3: apparent diameter degrees
• 4: apparent magnitude
• 5: horizontal parallax degrees (Moon)

Example inputs in parameter order: [2451545.0, 0, 258].

SW_SWE_RAD_MIDP

Native: double swe_rad_midp(double x1, double x0);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
x1	in	1	radians
x0	in	1	radians

Example inputs in parameter order: [350.0, 10.0].

SW_SWE_RADNORM

Native: double swe_radnorm(double x);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
x	in	1	radians

Example inputs in parameter order: [12.345].

SW_SWE_REFRAC

Native: double swe_refrac(double inalt, double atpress, double attemp, int32 calc_flag);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
inalt	in	1	altitude degrees
atpress	in	1	hPa (0 estimates pressure)
attemp	in	1	degrees Celsius
calc_flag	in	1	coordinate/refraction mode code

Example inputs in parameter order: [5.0, 1013.25, 15.0, 0].

SW_SWE_REFRAC_EXTENDED

Native: double swe_refrac_extended(double inalt, double geoalt, double atpress, double attemp, double lapse_rate, int32 calc_flag, double *dret);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
inalt	in	1	altitude degrees
geoalt	in	1	metres
atpress	in	1	hPa (0 estimates pressure)
attemp	in	1	degrees Celsius
lapse_rate	in	1	kelvin/metre
calc_flag	in	1	coordinate/refraction mode code
dret	out	4	true altitude deg; apparent altitude deg; refraction deg; dip deg

Output dret indices:

• 0: true altitude degrees
• 1: apparent altitude degrees
• 2: refraction degrees
• 3: horizon dip degrees

Example inputs in parameter order: [5.0, 34.0, 1013.25, 15.0, 0.0065, 0].

SW_SWE_REVJUL

Native: void swe_revjul(double jd, int gregflag, int *jyear, int *jmon, int *jday, double *jut);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
jd	in	1	Julian day TT or explicitly named input time scale
gregflag	in	1	0 Julian, 1 Gregorian
jyear	out	1	astronomical year
jmon	out	1	month 1..12
jday	out	1	day of month
jut	out	1	decimal hours

Example inputs in parameter order: [2451545.0, 1].

SW_SWE_RISE_TRANS

Native: int32 swe_rise_trans(double tjd_ut, int32 ipl, char *starname, int32 epheflag, int32 rsmi, double *geopos, double atpress, double attemp, double *tret, char *serr);

Family: Events. Return handling: rise.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
ipl	in	1	Swiss body ID
starname	in	256	star name, or empty to use ipl
epheflag	in	1	ephemeris flag bit mask
rsmi	in	1	rise/set/transit bit mask
geopos	in	3	degrees east; degrees north; metres above sea level
atpress	in	1	hPa (0 estimates pressure)
attemp	in	1	degrees Celsius
tret	out	1	Julian day UT1; 0 means unavailable contact
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 0, "", 2, 1, [13.405, 52.52, 34.0], 1013.25, 15.0].

SW_SWE_RISE_TRANS_TRUE_HOR

Native: int32 swe_rise_trans_true_hor(double tjd_ut, int32 ipl, char *starname, int32 epheflag, int32 rsmi, double *geopos, double atpress, double attemp, double horhgt, double *tret, char *serr);

Family: Events. Return handling: rise.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
ipl	in	1	Swiss body ID
starname	in	256	star name, or empty to use ipl
epheflag	in	1	ephemeris flag bit mask
rsmi	in	1	rise/set/transit bit mask
geopos	in	3	degrees east; degrees north; metres above sea level
atpress	in	1	hPa (0 estimates pressure)
attemp	in	1	degrees Celsius
horhgt	in	1	degrees
tret	out	1	Julian day UT1; 0 means unavailable contact
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, 0, "", 2, 1, [13.405, 52.52, 34.0], 1013.25, 15.0, 0.0].

SW_CMD_SET_ASTRO_MODELS

Native: void swe_set_astro_models(char *samod, int32 iflag);

Family: Configuration. Return handling: value. Upstream experimental.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
samod	in	256	experimental astronomical model/version specification
iflag	in	1	Swiss flag bit mask

Example inputs in parameter order: ["0,0,0,0,0,0,0,0", 258].

SW_CMD_SET_DELTA_T_USERDEF

Native: void swe_set_delta_t_userdef(double dt);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
dt	in	1	days; automatic sentinel -1e-10

Example inputs in parameter order: [-1e-10].

SW_CMD_SET_EPHE_PATH

Native: void swe_set_ephe_path(const char *path);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
path	in	256	absolute directory or path list, Windows ANSI encoding

Example inputs in parameter order: ["@DATA@"].

SW_CMD_SET_INTERPOLATE_NUT

Native: void swe_set_interpolate_nut(AS_BOOL do_interpolate);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
do_interpolate	in	1	C boolean 0 or 1

Example inputs in parameter order: [0].

SW_CMD_SET_JPL_FILE

Native: void swe_set_jpl_file(const char *fname);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
fname	in	256	JPL filename relative to configured data path

Example inputs in parameter order: ["de431.eph"].

SW_CMD_SET_LAPSE_RATE

Native: void swe_set_lapse_rate(double lapse_rate);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
lapse_rate	in	1	kelvin/metre

Example inputs in parameter order: [0.0065].

SW_CMD_SET_SID_MODE

Native: void swe_set_sid_mode(int32 sid_mode, double t0, double ayan_t0);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
sid_mode	in	1	sidereal mode ID and modifier bits; 255 user defined
t0	in	1	reference Julian day TT unless sidereal modifier changes it
ayan_t0	in	1	degrees

Example inputs in parameter order: [1, 2451545.0, 24.0].

SW_CMD_SET_TID_ACC

Native: void swe_set_tid_acc(double t_acc);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
t_acc	in	1	arcseconds/century squared; automatic sentinel 999999

Example inputs in parameter order: [999999.0].

SW_CMD_SET_TOPO

Native: void swe_set_topo(double geolon, double geolat, double geoalt);

Family: Configuration. Return handling: value.

Data: Configuration/state query; supplied paths/files must exist for subsequent calculations.

Argument	Direction	Capacity	Units
geolon	in	1	degrees east
geolat	in	1	degrees north
geoalt	in	1	metres

Example inputs in parameter order: [13.405, 52.52, 34.0].

SW_SWE_SIDTIME

Native: double swe_sidtime(double tjd_ut);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1

Example inputs in parameter order: [2451545.0].

SW_SWE_SIDTIME0

Native: double swe_sidtime0(double tjd_ut, double eps, double nut);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd_ut	in	1	Julian day UT1
eps	in	1	degrees
nut	in	1	degrees

Example inputs in parameter order: [2451545.0, 23.4392911, 0.0].

SW_SWE_SOL_ECLIPSE_HOW

Native: int32 swe_sol_eclipse_how(double tjd, int32 ifl, double *geopos, double *attr, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd	in	1	Julian day UT1
ifl	in	1	ephemeris flag bit mask
geopos	in	3	degrees east; degrees north; metres above sea level
attr	out	20	indexed event/phenomena attributes; see field reference
serr	out	256	diagnostic text

Output attr indices:

• 0: diameter fraction covered
• 1: Moon/object diameter ratio
• 2: disc obscuration fraction
• 3: core shadow diameter km
• 4: azimuth south through west degrees
• 5: true altitude degrees
• 6: apparent altitude degrees
• 7: Moon/object separation degrees
• 8: NASA magnitude
• 9: Saros series (-99999999 unavailable)
• 10: Saros member (-99999999 unavailable)

Example inputs in parameter order: [2451545.0, 2, [13.405, 52.52, 34.0]].

SW_SWE_SOL_ECLIPSE_WHEN_GLOB

Native: int32 swe_sol_eclipse_when_glob(double tjd_start, int32 ifl, int32 ifltype, double *tret, int32 backward, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_start	in	1	Julian day UT1
ifl	in	1	ephemeris flag bit mask
ifltype	in	1	event type bit mask
tret	out	10	Julian day UT1; 0 means unavailable contact
backward	in	1	0 forward, 1 backward; occultation one-try bit 32768
serr	out	256	diagnostic text

Output tret indices:

• 0: maximum JD UT1
• 1: local apparent noon JD UT1
• 2: eclipse begins JD UT1
• 3: eclipse ends JD UT1
• 4: totality begins JD UT1
• 5: totality ends JD UT1
• 6: centre line begins JD UT1
• 7: centre line ends JD UT1
• 8: reserved unimplemented
• 9: reserved unimplemented

Example inputs in parameter order: [2451545.0, 2, 0, 0].

SW_SWE_SOL_ECLIPSE_WHEN_LOC

Native: int32 swe_sol_eclipse_when_loc(double tjd_start, int32 ifl, double *geopos, double *tret, double *attr, int32 backward, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd_start	in	1	Julian day UT1
ifl	in	1	ephemeris flag bit mask
geopos	in	3	degrees east; degrees north; metres above sea level
tret	out	10	Julian day UT1; 0 means unavailable contact
attr	out	20	indexed event/phenomena attributes; see field reference
backward	in	1	0 forward, 1 backward; occultation one-try bit 32768
serr	out	256	diagnostic text

Output tret indices:

• 0: maximum JD UT1
• 1: first contact JD UT1
• 2: second contact JD UT1
• 3: third contact JD UT1
• 4: fourth contact JD UT1
• 5: sunrise JD UT1
• 6: sunset JD UT1
• 7: reserved
• 8: reserved
• 9: reserved

Output attr indices:

• 0: diameter fraction covered
• 1: Moon/object diameter ratio
• 2: disc obscuration fraction
• 3: core shadow diameter km
• 4: azimuth south through west degrees
• 5: true altitude degrees
• 6: apparent altitude degrees
• 7: Moon/object separation degrees
• 8: NASA magnitude
• 9: Saros series (-99999999 unavailable)
• 10: Saros member (-99999999 unavailable)

Example inputs in parameter order: [2451545.0, 2, [13.405, 52.52, 34.0], 0].

SW_SWE_SOL_ECLIPSE_WHERE

Native: int32 swe_sol_eclipse_where(double tjd, int32 ifl, double *geopos, double *attr, char *serr);

Family: Events. Return handling: event.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjd	in	1	Julian day UT1
ifl	in	1	ephemeris flag bit mask
geopos	out	10	degrees east; degrees north; metres above sea level
attr	out	20	indexed event/phenomena attributes; see field reference
serr	out	256	diagnostic text

Output geopos indices:

• 0: central longitude degrees east
• 1: central latitude degrees north

Output attr indices:

• 0: diameter fraction covered
• 1: Moon/object diameter ratio
• 2: disc obscuration fraction
• 3: core shadow diameter km
• 4: azimuth south through west degrees
• 5: true altitude degrees
• 6: apparent altitude degrees
• 7: Moon/object separation degrees
• 8: NASA magnitude
• 9: Saros series (-99999999 unavailable)
• 10: Saros member (-99999999 unavailable)

Example inputs in parameter order: [2451545.0, 2].

SW_SWE_SOLCROSS

Native: double swe_solcross(double x2cross, double jd_et, int32 flag, char *serr);

Family: Events. Return handling: crossing.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
x2cross	in	1	target ecliptic longitude, degrees
jd_et	in	1	Julian day TT or explicitly named input time scale
flag	in	1	Swiss flag bit mask
serr	out	256	diagnostic text

Example inputs in parameter order: [0.0, 2451545.0, 258].

SW_SWE_SOLCROSS_UT

Native: double swe_solcross_ut(double x2cross, double jd_ut, int32 flag, char *serr);

Family: Events. Return handling: crossing.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
x2cross	in	1	target ecliptic longitude, degrees
jd_ut	in	1	Julian day UT1
flag	in	1	Swiss flag bit mask
serr	out	256	diagnostic text

Example inputs in parameter order: [0.0, 2451545.0, 258].

SW_SWE_SPLIT_DEG

Native: void swe_split_deg(double ddeg, int32 roundflag, int32 *ideg, int32 *imin, int32 *isec, double *dsecfr, int32 *isgn);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
ddeg	in	1	degrees
roundflag	in	1	split-degree bit mask
ideg	out	1	whole degrees
imin	out	1	minutes
isec	out	1	arcseconds
dsecfr	out	1	fractional arcsecond
isgn	out	1	sign or zodiac index selected by roundflag

Example inputs in parameter order: [123.456, 0].

SW_SWE_TIME_EQU

Native: int32 swe_time_equ(double tjd, double *te, char *serr);

Family: Time. Return handling: status.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
tjd	in	1	Julian day UT1
te	out	1	days (apparent minus mean solar time)
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0].

SW_SWE_TOPO_ARCUS_VISIONIS

Native: int32 swe_topo_arcus_visionis(double tjdut, double *dgeo, double *datm, double *dobs, int32 helflag, double mag, double azi_obj, double alt_obj, double azi_sun, double azi_moon, double alt_moon, double *dret, char *serr);

Family: Heliacal. Return handling: status. Upstream experimental.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjdut	in	1	Julian day UT1
dgeo	in	3	degrees east; degrees north; metres above sea level
datm	inout	4	hPa; Celsius; relative humidity percent; visibility km or extinction coefficient
dobs	inout	6	age years; Snellen ratio; binocular flag; magnification; aperture mm; transmission fraction
helflag	in	1	heliacal flag bit mask
mag	in	1	astronomical magnitude
azi_obj	in	1	azimuth degrees
alt_obj	in	1	altitude degrees
azi_sun	in	1	azimuth degrees
azi_moon	in	1	azimuth degrees
alt_moon	in	1	altitude degrees
dret	out	1	arcus visionis degrees
serr	out	256	diagnostic text

Example inputs in parameter order: [2451545.0, [13.405, 52.52, 34.0], [1013.25, 15.0, 40.0, 0.0], [36.0, 1.0, 0.0, 1.0, 0.0, 0.0], 0, 0.0, 90.0, 5.0, 100.0, 110.0, -10.0].

SW_SWE_UTC_TIME_ZONE

Native: void swe_utc_time_zone(int32 iyear, int32 imonth, int32 iday, int32 ihour, int32 imin, double dsec, double d_timezone, int32 *iyear_out, int32 *imonth_out, int32 *iday_out, int32 *ihour_out, int32 *imin_out, double *dsec_out);

Family: Time. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
iyear	in	1	astronomical year
imonth	in	1	month 1..12
iday	in	1	day of month
ihour	in	1	hour 0..23
imin	in	1	minutes
dsec	in	1	seconds, leap second allowed where documented
d_timezone	in	1	hours east of UTC (fractional allowed)
iyear_out	out	1	astronomical year
imonth_out	out	1	month 1..12
iday_out	out	1	day of month
ihour_out	out	1	hour 0..23
imin_out	out	1	minutes
dsec_out	out	1	seconds

Example inputs in parameter order: [2000, 1, 1, 12, 0, 0.0, 5.5].

SW_SWE_UTC_TO_JD

Native: int32 swe_utc_to_jd(int32 iyear, int32 imonth, int32 iday, int32 ihour, int32 imin, double dsec, int32 gregflag, double *dret, char *serr);

Family: Time. Return handling: status.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
iyear	in	1	astronomical year
imonth	in	1	month 1..12
iday	in	1	day of month
ihour	in	1	hour 0..23
imin	in	1	minutes
dsec	in	1	seconds, leap second allowed where documented
gregflag	in	1	0 Julian, 1 Gregorian
dret	out	2	Julian day TT, Julian day UT1
serr	out	256	diagnostic text

Output dret indices:

• 0: Julian day TT
• 1: Julian day UT1

Example inputs in parameter order: [2000, 1, 1, 12, 0, 0.0, 1].

SW_SWE_VERSION

Native: char * swe_version(char *);

Family: Utilities. Return handling: value.

Data: No binary data normally required; delta-T/leap-second model applies to time conversions.

Argument	Direction	Capacity	Units
arg1	out	256	NUL-terminated string

Example inputs in parameter order: [].

SW_SWE_VIS_LIMIT_MAG

Native: int32 swe_vis_limit_mag(double tjdut, double *geopos, double *datm, double *dobs, char *ObjectName, int32 helflag, double *dret, char *serr);

Family: Heliacal. Return handling: visibility.

Data: Body/date/flags determine files: sepl_18.se1, semo_18.se1, seas_18.se1; external asteroid/JPL files where requested.

Argument	Direction	Capacity	Units
tjdut	in	1	Julian day UT1
geopos	in	3	degrees east; degrees north; metres above sea level
datm	inout	4	hPa; Celsius; relative humidity percent; visibility km or extinction coefficient
dobs	inout	6	age years; Snellen ratio; binocular flag; magnification; aperture mm; transmission fraction
ObjectName	in	256	planet or fixed-star name
helflag	in	1	heliacal flag bit mask
dret	out	10	limiting magnitude; object alt/az deg; Sun alt/az deg; Moon alt/az deg; object magnitude
serr	out	256	diagnostic text

Output dret indices:

• 0: limiting magnitude
• 1: object altitude degrees
• 2: object azimuth degrees
• 3: Sun altitude degrees
• 4: Sun azimuth degrees
• 5: Moon altitude degrees
• 6: Moon azimuth degrees
• 7: object magnitude

Example inputs in parameter order: [2451545.0, [13.405, 52.52, 34.0], [1013.25, 15.0, 40.0, 0.0], [36.0, 1.0, 0.0, 1.0, 0.0, 0.0], "venus", 0].