swephR: High Precision Swiss Ephemeris

Description

The Swiss Ephemeris (version 2.10.03) is a high precision ephemeris based upon the DE431 ephemerides from NASA's JPL. It covers the time range 13201 BCE to 17191 CE. This package uses the semi-analytic theory by Steve Moshier. For faster and more accurate calculations, the compressed Swiss Ephemeris data is available in the 'swephRdata' package. To access this data package, run 'install.packages("swephRdata", repos = "https://rstub.r-universe.dev", type = "source")'. The size of the 'swephRdata' package is approximately 115 MB. The user can also use the original JPL DE431 data.

Author(s)

Maintainer: Ralf Stubner ralf.stubner@gmail.com

Authors:

• Victor Reijs

• Authors and copyright holder of the Swiss Ephemeris [copyright holder]

See Also

Useful links:

• https://github.com/rstub/swephR/

• https://rstub.github.io/swephR/

• https://www.astro.com/swisseph/

• Report bugs at https://github.com/rstub/swephR/issues/

Constants used in swephR

Description

• name of variable

• value of the variable

Usage

data(SE)

Format

A data frame with 217 rows and 2 variables

Section 1: The Ephemeris file related functions

Description

Several initialization functions

Usage

swe_set_ephe_path(path)

swe_close()

swe_set_jpl_file(fname)

swe_version()

swe_get_library_path()

Arguments

Details

swe_set_ephe_path()

This is the first function that should be called before any other function of the Swiss Ephemeris. Even if you don't want to set an ephemeris path and use the Moshier ephemeris, it is nevertheless recommended to call swe_set_ephe_path(NULL), because this function makes important initializations. If you don't do that, the Swiss Ephemeris may work, but the results may be not 100% consistent.

swe_close()

At the end of your computations this function releases most resources (open files and allocated memory) used by Swiss Ephemeris.

swe_set_jpl_file()

Set name of JPL ephemeris file.

swe_version()

The function provides the version number of the Swiss Ephemeris software.

swe_get_library_path()

The function provides the path where the executable resides.

Value

swe_version returns Swiss Ephemeris software version as string

swe_get_library_path returns the path in which the executable resides as string

See Also

Section 1 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

## Not run: swe_set_ephe_path("c:\\sweph\\ephe")
swe_close()
swe_set_jpl_file("de431.eph")
swe_version()
swe_get_library_path()

Section 10: Sidereal mode functions

Description

Functions to support the determination of sidereal information

Usage

swe_set_sid_mode(sid_mode, t0, ayan_t0)

swe_get_ayanamsa_name(sid_mode)

swe_get_ayanamsa_ex_ut(jd_ut, iflag)

swe_get_ayanamsa_ex(jd_et, iflag)

Arguments

Details

swe_set_sid_mode()

Set the mode for sidereal computations.

swe_get_ayanamsa_name()

Get the mode name for sidereal computations.

swe_get_ayanamsa_ex_ut()

It computes ayanamsa using UT.

swe_get_ayanamsa_ex()

It computes ayanamsa using ET.

Value

swe_get_ayanamsa_name returns name of ayanamsa method as string

swe_get_ayanamsa_ex_ut returns a list with named entries: return status flag as integer, daya ayanamsa value as double and serr error message as string

swe_get_ayanamsa_ex returns a list with named entries: return status flag as integer, daya ayanamsa value as double and serr error message as string

See Also

Section 10 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

data(SE)
swe_set_sid_mode(SE$SIDM_FAGAN_BRADLEY,0,0)
swe_get_ayanamsa_name(SE$SIDM_FAGAN_BRADLEY)
swe_get_ayanamsa_ex_ut(2458346.82639,SE$FLG_MOSEPH)
swe_get_ayanamsa_ex(2458346.82639,SE$FLG_MOSEPH)

Section 13: House cusp, ascendant and Medium Coeli calculations

Description

Calculate house cusp, ascendant, Medium Coeli, etc. calculations

Usage

swe_houses_ex(jd_ut, cuspflag, geolat, geolon, hsys)

swe_houses_armc(armc, geolat, eps, hsys)

swe_house_name(hsys)

Arguments

Details

swe_houses_ex()

Calculate houses' cusps, ascendant, Medium Coeli (MC), etc.

swe_houses_armc()

Calculate houses' information from the right ascension of the Medium Coeli (MC).

swe_houses_name()

Provide the house name.

Value

swe_houses_ex returns a list with named entries: return status flag as integer, cusps cusps values as double and ascmc ascendent, MCs. etc. as double.

swe_houses_armc returns a list with named entries: return status flag as integer, cusps cusps values as double and ascmc ascendent, MCs, etc. as double.

swe_house_name returns the house name as string

See Also

Section 13 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

swe_houses_ex(1234567, 0, 53, 0, 'B')
swe_houses_armc(12, 53, 23, 'B')
swe_house_name('G')

Section 14: House position calculations

Description

Calculate house position of a given body.

Usage

swe_house_pos(armc, geolat, eps, hsys, xpin)

swe_gauquelin_sector(
  jd_ut,
  ipl,
  starname,
  ephe_flag,
  imeth,
  geopos,
  atpress,
  attemp
)

Arguments

Details

swe_house_pos()

Calculate house position of given body.

swe_gauquelin_sector()

Compute the Gauquelin sector position of a planet or star.

Value

swe_house_pos returns a list with named entries: return how far from body's cusp as double, and serr error message as string.

swe_gauquelin_sector returns a list with named entries: return status flag as integer, dgsect for Gauquelin sector as double and serr error message as string

See Also

Section 14 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

swe_house_pos(12, 53, 23, 'B', c(0,0))
data(SE)
swe_gauquelin_sector(1234567.5,SE$VENUS,"",SE$FLG_MOSEPH,0,c(0,50,10),1013.25,15)

Section 15: Sidereal time

Description

Calculate the sidereal time (in degrees).

Usage

swe_sidtime(jd_ut)

Arguments

Details

swe_sidtime()

Determine the sidereal time.

Value

swe_sidtime returns the sidereal time as double (deg)

See Also

Section 15 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

swe_sidtime(2451545)

Section 16.7: Other functions that may be useful

Description

Useful functions

Usage

swe_day_of_week(jd)

Arguments

Details

swe_day_of_week()

Determine day of week from Julian day number.

Value

swe_day_of_week returns the day of week as integer vector (0 Monday .. 6 Sunday)

See Also

Section 16.7 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

swe_day_of_week(1234.567)

Section 2: Computing positions

Description

Computing positions of planets, asteroids, lunar nodes and apogees using Swiss Ephemeris.

Usage

swe_calc_ut(jd_ut, ipl, iflag)

swe_calc(jd_et, ipl, iflag)

Arguments

Details

swe_calc_ut()

It compute positions using UT.

swe_calc()

It compute positions using ET.

Value

swe_calc_ut returns a list with named entries: return status flag as integer, xx information on planet position, and serr error message as string.

swe_calc returns a list with named entries: return status flag as integer, xx updated star name as string and serr error message as string.

See Also

Section 2 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

data(SE)
swe_calc_ut(2458346.82639, SE$MOON, SE$FLG_MOSEPH)
swe_calc(2458346.82639, SE$MOON, SE$FLG_MOSEPH)

Section 3: Find a planetary or asteroid name

Description

Find a planetary or asteroid name.

Usage

swe_get_planet_name(ipl)

Arguments

Details

swe_get_planet_name()

Convert object number into object name.

Value

swe_get_planet_name returns the object's name as string

See Also

Section 3 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

data(SE)
swe_get_planet_name(SE$MOON)

Section 4: Fixed stars functions

Description

The following functions are used to calculate positions of fixed stars.

Usage

swe_fixstar2_mag(starname)

swe_fixstar2(starname, jd_et, iflag)

swe_fixstar2_ut(starname, jd_ut, iflag)

Arguments

Details

swe_fixstar2_mag()

Calculate visible magnitude (Vmag) of star.

swe_fixstar2()

Compute information of star using ET.

swe_fixstar2_ut()

Compute information of star using UT

Value

swe_fixstar2_mag returns a list with named entries: return status flag as integer, starname updated star name as string, mag magnitude of star as double, and serr for error message as string.

swe_fixstar2 returns a list with named entries: return status flag as integer, starname updated star name as string, xx star phenomena as numeric vector, and serr error message as string.

swe_fixstar2_ut returns a list with named entries: return status flag as integer, starname updated star name as string, xx star information as numeric vector, and serr for error message as string.

See Also

Section 4 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

data(SE)
swe_fixstar2_mag("sirius")
swe_set_topo(0,50,10)
swe_fixstar2("sirius",1234567,SE$FLG_TOPOCTR+SE$FLG_MOSEPH+SE$FLG_EQUATORIAL)
swe_fixstar2_ut("sirius",1234567,SE$FLG_TOPOCTR+SE$FLG_MOSEPH+SE$FLG_EQUATORIAL)

Section 5: Kepler elements, nodes, apsides and orbital periods

Description

Functions for: determining Kepler elements, nodes, apsides and orbital periods

Usage

swe_nod_aps_ut(jd_ut, ipl, iflag, method)

swe_nod_aps(jd_et, ipl, iflag, method)

swe_get_orbital_elements(jd_et, ipl, iflag)

swe_orbit_max_min_true_distance(jd_et, ipl, iflag)

Arguments

Details

swe_nod_aps_ut()

Compute planetary nodes and apsides (perihelia, aphelia, second focal points of the orbital ellipses).

swe_nod_aps()

Compute planetary nodes and apsides (perihelia, aphelia, second focal points of the orbital ellipses).

swe_get_orbital_elements()

This function calculates osculating elements (Kepler elements) and orbital periods.

swe_orbit_max_min_true_distance()

This function calculates the maximum possible distance, the minimum possible distance and the current true distance of planet.

Value

swe_nod_aps_ut returns a list with named entries: return status flag as integer, xnasc ascending nodes as numeric vector, xndsc descending nodes as numeric vector, xperi perihelion as numeric vector, xaphe aphelion as numeric vector and serr error message as string

swe_nod_aps returns a list with named entries: return status flag as integer, xnasc ascending nodes as numeric vector, xndsc descending nodes as numeric vector, xperi perihelion as numeric vector, xaphe aphelion as numeric vector and serr error message as string

swe_get_orbital_elements returns a list with named entries: return status flag as integer, dret function results as numeric vector and serr error message as string

swe_orbit_max_min_true_distance returns a list with named entries: return status flag as integer, dmax maximum distance as double, dmin minimum distance as double, dtrue true distance as double and serr error message as string

See Also

Section 5 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

data(SE)
swe_nod_aps_ut(2451545,SE$MOON, SE$FLG_MOSEPH,SE$NODBIT_MEAN)
swe_nod_aps(2451545,SE$MOON, SE$FLG_MOSEPH,SE$NODBIT_MEAN)
swe_get_orbital_elements(2451545,SE$MOON, SE$FLG_MOSEPH)
swe_orbit_max_min_true_distance(2451545,SE$MOON, SE$FLG_MOSEPH)

Section 6: Eclipses, Risings, Settings, Meridian Transits, Planetary Phenomena

Description

Functions for: determining eclipse and occultation calculations, computing the times of rising, setting and meridian transits for all planets, asteroids, the moon and the fixed stars; computing phase, phase angle, elongation, apparent diameter, apparent magnitude for the Sun, the Moon, all planets and asteroids; and determining heliacal phenomenon after a given start date

Usage

swe_sol_eclipse_when_loc(jd_start, ephe_flag, geopos, backward)

swe_sol_eclipse_when_glob(jd_start, ephe_flag, ifltype, backward)

swe_sol_eclipse_how(jd_ut, ephe_flag, geopos)

swe_sol_eclipse_where(jd_ut, ephe_flag)

swe_lun_occult_when_loc(jd_start, ipl, starname, ephe_flag, geopos, backward)

swe_lun_occult_when_glob(jd_start, ipl, starname, ephe_flag, ifltype, backward)

swe_lun_occult_where(jd_ut, ipl, starname, ephe_flag)

swe_lun_eclipse_when_loc(jd_start, ephe_flag, geopos, backward)

swe_lun_eclipse_how(jd_ut, ephe_flag, geopos)

swe_lun_eclipse_when(jd_start, ephe_flag, ifltype, backward)

swe_rise_trans_true_hor(
  jd_ut,
  ipl,
  starname,
  ephe_flag,
  rsmi,
  geopos,
  atpress,
  attemp,
  horhgt
)

swe_pheno_ut(jd_ut, ipl, ephe_flag)

swe_pheno(jd_et, ipl, ephe_flag)

swe_azalt(jd_ut, coord_flag, geopos, atpress, attemp, xin)

swe_azalt_rev(jd_ut, coord_flag, geopos, xin)

swe_refrac(InAlt, atpress, attemp, calc_flag)

swe_refrac_extended(InAlt, height, atpress, attemp, lapse_rate, calc_flag)

swe_heliacal_ut(jd_utstart, dgeo, datm, dobs, objectname, event_type, helflag)

swe_vis_limit_mag(jd_ut, dgeo, datm, dobs, objectname, helflag)

swe_heliacal_pheno_ut(jd_ut, dgeo, datm, dobs, objectname, event_type, helflag)

swe_topo_arcus_visionis(
  jd_ut,
  dgeo,
  datm,
  dobs,
  helflag,
  mag,
  AziO,
  AltO,
  AziS,
  AziM,
  AltM
)

swe_heliacal_angle(
  jd_ut,
  dgeo,
  datm,
  dobs,
  helflag,
  mag,
  AziO,
  AziS,
  AziM,
  AltM
)

Arguments

Details

swe_sol_eclipse_when_loc()

Find the next solar eclipse for a given geographic position.

swe_sol_eclipse_when_glob()

Find the next solar eclipse on earth.

swe_sol_eclipse_how()

Compute the attributes of a solar eclipse for a given time.

swe_sol_eclipse_where()

Compute the geographic position of a solar eclipse path.

swe_lun_occult_when_loc()

Find the next lunar occultation with planet or star at a certain position.

swe_lun_occult_when_glob()

Find the next lunar occultation with planet or star somewhere on the earth.

swe_lun_occult_where()

Compute the geographic position of an occultation path.

swe_lun_eclipse_when_loc()

Find the next lunar eclipse for a given geographic position.

swe_lun_eclipse_how()

Compute the attributes of a lunar eclipse for a given time.

swe_lun_eclipse_when()

Find the next lunar eclipse on earth.

swe_rise_trans_true_hor()

Compute the times of rising, setting and meridian transits for planets, asteroids, the moon, and the fixed stars for a local horizon that has an altitude.

swe_pheno_ut()

Compute phase, phase angle, elongation, apparent diameter, apparent magnitude for the Sun, the Moon, all planets and asteroids (UT)

swe_pheno()

Compute phase, phase angle, elongation, apparent diameter, apparent magnitude for the Sun, the Moon, all planets and asteroids (ET).

swe_azalt()

Compute the horizontal coordinates (azimuth and altitude) of a planet or a star from either ecliptical or equatorial coordinates.

swe_azalt_rev()

Compute either ecliptical or equatorial coordinates from azimuth and true altitude. If only an apparent altitude is given, the true altitude has to be computed first with e.g. the function swe_refrac_extended().

swe_refrac()

Calculate either the topocentric altitude from the apparent altitude or the apparent altitude from the topocentric altitude.

swe_refrac_extended()

Calculate either the topocentric altitude from the apparent altitude or the apparent altitude from the topocentric altitude. It allows correct calculation of refraction for heights above sea > 0, where the ideal horizon and planets that are visible may have a negative altitude.

swe_heliacal_ut()

Compute the Julian day of the next heliacal phenomenon after a given UT start date. It works between geographic latitudes 60 South and 60 North.

swe_vis_limit_mag()

Determine the limiting visual magnitude in dark skies. If the visual magnitude mag of an object is known for a given date (e. g. from a call of function swe_pheno_ut(), and if magnitude is smaller than the value returned by swe_vis_limit_mag(), then it is visible.

swe_heliacal_pheno_ut()

Provide data that are relevant for the calculation of heliacal risings and settings. This function does not provide data of heliacal risings and settings itself, just some additional data mostly used for test purposes. To calculate heliacal risings and settings, use the function swe_heliacal_ut().

swe_topo_arcus_visionis()

Compute topocentric arcus visionis.

swe_heliacal_angle()

Compute heliacal angle.

Value

swe_sol_eclipse_when_loc returns a list with named entries: return status flag as integer, tret for eclipse timing moments as numeric vector, attr phenomena during eclipse as numeric vector and serr error message as string

swe_sol_eclipse_when_glob returns a list with named entries: return status flag as integer, tret for eclipse timing moments as numeric vector and serr error warning as string

swe_sol_eclipse_how returns a list with named entries: return status flag as integer, attr phenomena during eclipse as numeric vector and serr error message as string

swe_sol_eclipse_where returns a list with named entries: return status flag as integer, pathpos geographic path positions as numeric vector, attr phenomena during eclipse as numeric vector and serr error message as string

swe_lun_occult_when_loc returns a list with named entries: return status flag as integer, tret for eclipse timing moments as numeric vector, attr phenomena during eclipse as numeric vector and serr error message as string

swe_lun_occult_when_glob returns a list with named entries: return status flag as integer, tret for eclipse timing moments as numeric vector, attr phenomena during eclipse as numeric vector and serr error message as string

swe_lun_occult_where returns a list with named entries: return status flag as integer, pathpos geographic path positions as numeric vector, attr phenomena during eclipse as numeric vector and serr error message as string

swe_lun_eclipse_when_loc returns a list with named entries: return status flag as integer, tret for eclipse timing moments, attr phenomena during eclipse and serr error warning as string

swe_lun_eclipse_how returns a list with named entries: return status flag as integer, attr phenomena during eclipse as numeric vector and serr error message as string

swe_lun_eclipse_when returns a list with named entries: return status flag as integer, tret for eclipse timing moments as numeric vector and serr error warning as string

swe_rise_trans_true_hor returns a list with named entries: return status flag as integer, tret for azimuth/altitude info as double and serr error message as string

swe_pheno_ut returns a list with named entries: return status fag as integer, attr for phenomenon information as numeric vector and serr error warning as string

swe_pheno returns a list with named entries: return status fag as integer, attr for phenomenon information as numeric vector and serr error message as string

swe_azalt returns a list with named entries: xaz for azi/alt info as numeric vector.

swe_azalt_rev returns a list with named entries: xaz for celestial info as numeric vector.

swe_refrac returns the (apparent/topocentric) altitude as double (deg)

swe_refrac_extended returns a list with named entries: return status flag as integer, dret refraction results as numeric vector (TopoAlt, AppAlt, refraction)

swe_heliacal_ut returns a list with named entries return status flag as integer, dret heliacal results as numeric vector, and serr error message as string.

swe_vis_limit_mag returns a list with named entries: return status flag as integer, dret limiting magnitude as double and serr error message as string

swe_heliacal_pheno_ut returns a list with named entries: return status flag as integer darr for heliacal details as numeric vector and serr error message as string

swe_topo_arcus_visionis returns a list with named entries: return status flag as integer, darr heliacal details as numeric vector and serr error message as string

swe_heliacal_angle returns a list with named entries: return status flag as integer, dret heliacal angle as numeric vector and serr error message as string

See Also

Section 6 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

data(SE)
swe_sol_eclipse_when_loc(1234567,SE$FLG_MOSEPH,c(0,50,10),FALSE)
swe_sol_eclipse_when_glob(1234567,SE$FLG_MOSEPH,SE$ECL_TOTAL+SE$ECL_CENTRAL+SE$ECL_NONCENTRAL,FALSE)
swe_sol_eclipse_how(1234580.19960447,SE$FLG_MOSEPH,c(0,50,10))
swe_sol_eclipse_where(1234771.68584597,SE$FLG_MOSEPH)
swe_lun_occult_when_loc(1234567,SE$VENUS,"",SE$FLG_MOSEPH+SE$ECL_ONE_TRY,c(0,50,10),FALSE)
swe_lun_occult_when_glob(1234567,SE$VENUS,"",SE$FLG_MOSEPH+SE$ECL_ONE_TRY,SE$ECL_TOTAL,FALSE)
swe_lun_occult_where(1234590.44756319,SE$VENUS,"",SE$FLG_MOSEPH+SE$ECL_ONE_TRY)
swe_lun_eclipse_when_loc(1234567,SE$FLG_MOSEPH,c(0,50,10),FALSE)
swe_lun_eclipse_when(1234567,SE$FLG_MOSEPH,SE$ECL_CENTRAL,FALSE)
swe_lun_eclipse_how(1234580.19960447,SE$FLG_MOSEPH,c(0,50,10))
swe_rise_trans_true_hor(1234567.5,SE$SUN,"",SE$FLG_MOSEPH,0,c(0,50,10),1013.25,15,0)
swe_pheno_ut(1234567,1,SE$FLG_MOSEPH)
swe_pheno(1234567,1,SE$FLG_MOSEPH)
swe_azalt(1234567,SE$EQU2HOR,c(0,50,10),15,1013.25,c(186,22))
swe_azalt_rev(1234567,SE$ECL2HOR,c(0, 50,10),c(123,2))
swe_refrac_extended(2,0,1013.25,15,-0.065,SE$TRUE_TO_APP)
swe_heliacal_ut(1234567,c(0,50,10),c(1013.25,15,50,0.25),c(25,1,1,1,5,0.8),"sirius",
  SE$HELIACAL_RISING,SE$HELFLAG_HIGH_PRECISION+SE$FLG_MOSEPH)
swe_vis_limit_mag(1234567.5,c(0,50,10),c(1013.25,15,20,0.25),c(25,1,1,1,5,0.8),'sirius',
  SE$HELFLAG_HIGH_PRECISION+SE$FLG_MOSEPH)
swe_heliacal_pheno_ut(1234567.5,c(0,50,10),c(1013.25,15,20,0.25),c(25,1,1,1,5,0.8),'sirius',
  SE$HELIACAL_RISING,SE$HELFLAG_HIGH_PRECISION+SE$FLG_MOSEPH)
swe_topo_arcus_visionis(1234567.5,c(0,50,10),c(1013.25,15,20,0.25),c(25,1,1,1,5,0.8),
  SE$HELFLAG_HIGH_PRECISION+SE$HELFLAG_OPTICAL_PARAMS,-1,124,2,120,0,-45)
swe_heliacal_angle(1234567.5,c(0,50,10),c(1013.25,15,20,0.25),c(25,1,1,1,5,0.8),
  SE$HELFLAG_HIGH_PRECISION+SE$HELFLAG_OPTICAL_PARAMS,-1,124,120,0,-45)

Section 7: Date and time conversion functions

Description

Functions related to calendar and time conversions.

Usage

swe_julday(year, month, day, hourd, gregflag)

swe_date_conversion(year, month, day, hourd, cal)

swe_revjul(jd, gregflag)

swe_utc_time_zone(year, month, day, houri, min, sec, d_timezone)

swe_utc_to_jd(year, month, day, houri, min, sec, gregflag)

swe_jdet_to_utc(jd_et, gregflag)

swe_jdut1_to_utc(jd_ut, gregflag)

swe_time_equ(jd_ut)

swe_lmt_to_lat(jd_lmt, geolon)

swe_lat_to_lmt(jd_lat, geolon)

Arguments

Details

swe_julday()

Convert calendar dates to the astronomical time scale which measures time in Julian day number.

swe_date_conversion()

Convert calendar dates to the astronomical time scale which measures time in Julian day number and checks if the calendar date is legal.

swe_revjul()

Compute year, month, day and hour from a Julian day number.

swe_utc_time_zone()

Convert local time to UTC and UTC to local time.

swe_utc_to_jd()

Convert UTC to Julian day number (UT and ET).

swe_jdet_to_utc()

Convert Julian day number (ET) into UTC.

swe_jdut1_to_utc()

Convert Julian day number (UT1) into UTC.

swe_time_equ()

Calculate equation of time (LAT-LMT).

swe_lmt_to_lat()

Convert Julian day number (LMT) into Julian day number (LAT).

swe_lat_to_lmt()

Convert Julian day number (LAT) into Julian day number (LMT).

Value

swe_date_conversion returns a list with named entries: return status flag as integer, jd Julian day number as double

swe_revjul returns a list with named entries: year year as integer, month month as integer, day day as integer and hour hour as double.

swe_utc_time_zone returns a list with named entries: year_out year as integer, month_out month as integer, day_out day as integer, hour_out hour as integer, min_out minute as integer, sec_out second as double,

swe_utc_to_jd returns a list with named entries: return status flag as integer, dret Julian day number as numeric vector and serr for error message as string.

swe_jdet_to_utc returns a list with named entries: year_out year as integer, month_out month as integer, day_out day as integer, hour_out hour as integer, min_out minute as integer, sec_out second as double,

swe_jdut1_to_utc returns a list with named entries: year_out year as integer, month_out month as integer, day_out day as integer, hour_out hour as integer, min_out minute as integer, sec_out second as double,

swe_swe_time_equ returns a list with named entries: return status flag as integer, e equation of time (day) as double and serr for error message as string.

swe_lmt_to_lat returns a list with named entries: return status flag as integer, jd_lat Julian day number (LAT) (day) as double and serr for error message as string.

swe_lat_to_lmt returns a list with named entries: return status flag as integer, jd_lmt Julian day number (LMT) (day) as double and serr for error message as string.

See Also

Section 7 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

data(SE)
swe_julday(2000,1,1,12,SE$GREG_CAL)
swe_date_conversion(2000,1,1,12,"g")
swe_revjul(2452500,SE$GREG_CAL)
swe_utc_time_zone(2000,1,1,12,5,1.2,2)
swe_utc_to_jd(2000,1,1,0,12,3.4,SE$GREG_CAL)
swe_jdet_to_utc(2452500,SE$GREG_CAL)
swe_jdut1_to_utc(2452500,SE$GREG_CAL)
swe_time_equ(2452500)
swe_lmt_to_lat(2452500,0)
swe_lat_to_lmt(2452500,0)

Section 8: Delta T-related functions

Description

Functions related to DeltaT and tidal acceleration

Usage

swe_deltat_ex(jd_ut, ephe_flag)

swe_deltat(jd_ut)

swe_set_tid_acc(t_acc)

swe_get_tid_acc()

swe_set_delta_t_userdef(delta_t)

Arguments

Details

swe_deltat_ex()

Determine DeltaT from Julian day number for a specific ephemeris.

swe_deltat()

Determine DeltaT from Julian day number for a used ephemeris. This function is only safe if:

• your software consistently uses the same ephemeris flag

• if software consistently uses the same ephemeris files (with SE$FLG_SWIEPH and SE$FLG_MOSEPH)

• if swe_set_ephe_path() is first called (with SE$FLG_SWIEPH) and swe_set_jpl_file() (with SE$FLG_JPLEPH)

swe_set_tid_acc()

Set the tidal acceleration.

swe_get_tid_acc()

Get the present configured tidal acceleration.

swe_set_delta_t_userdef()

Allows the user to set a fixed DeltaT value that will be returned by swe_deltat() or swe_deltat_ex().

Value

swe_deltat_ex returns a list with named entries: deltat for DeltaT as double (day) and serr for error message as string.

swe_deltat returns the DeltaT as double (day)

swe_get_tid_acc returns the tidal acceleration as double (arcsec/century^2)

See Also

Section 8 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

data(SE)
swe_deltat_ex(1234.567, SE$FLG_MOSEPH)
swe_deltat(1234.567)
swe_set_tid_acc(1.23)
swe_get_tid_acc()
swe_set_delta_t_userdef(0.23)

Section 9: The function for calculating topocentric planet position

Description

Function for topocentric planet positions

Usage

swe_set_topo(longitude, lat, height)

Arguments

Details

swe_set_topo()

Set the topocentric location of the observer.

See Also

Section 9 in https://www.astro.com/swisseph/swephprg.htm. Remember that array indices start in R at 1, while in C they start at 0!

Examples

swe_set_topo(0,50,10)