Astronomical Utilities

New in version 0.2.

lsl.astro.B1950_UTC_JD = 2433282.4235

UTC Julian day of J2000.0 coordinate epoch.

lsl.astro.B1950_to_J2000(pos)

Convert B1950 epoch to J2000 epoch for equatorial coordinates.

Param: pos - object of type equ_posn giving B1950 coordinates

Returns: object of type equ_posn giving J2000 coordinates.

Note

The accuracy of this function is about 0.01 degrees.

lsl.astro.DJD_OFFSET = 2415020.0

Offset in days between UNIX time (epoch 1970/01/01) and standard Julian day.

lsl.astro.J2000_UTC_JD = 2451545.0

Difference in seconds between TT and TAI times.

lsl.astro.J2000_to_B1950(pos)

Convert J2000 epoch to B1950 epoch for equatorial coordinates.

Param: pos - object of type equ_posn giving J2000 coordinates

Returns: object of type equ_posn giving B1950 coordinates.

Note

The accuracy of this function is about 0.01 degrees.

lsl.astro.MJD_OFFSET = 2400000.5

Offset in days between standard Julian day and Dublin Julian day.

lsl.astro.SECS_IN_DAY = 86400.0

UTC Julian day of B1950.0 coordinate epoch.

lsl.astro.TAI_TT_OFFSET = 32.184

” Velocity of light in meters/second.

lsl.astro.UNIX_OFFSET = 2440587.5

The number of seconds in one day

lsl.astro.add_hms(source, dest)

Adds time/angle hours, minutes, seconds.

Param: source - Object of type hms represeting angle 1. Param: dest - Object of type hms represeting angle 2.

Returns object of type hms representing sum of angles.

lsl.astro.add_secs_hms(hms, seconds)

Add seconds to time/angle hours, minutes, seconds.

Param: hms - Object of type hms representing angle. Param: seconds - Seconds offset (float) to add to angle.

Returns object of type hms representing angle + offset.

class lsl.astro.date(years=2000, months=1, days=1, hours=0, minutes=0, seconds=0.0)

Represents UT time in calendar units.

Public members:
years - Date years (integer). months - Date months (integer). days - Date days (integer). hours - Date hours (integer). minutes - Date minutes (integer). seconds - Date seconds (float).
load(dateStr, timeStr)

Load date object from formatted strings.

Param: dateStr - A string of format YYYY-MM-DD giving date. Param: timeStr - A string of format HH:MM:SS.S giving time.

to_jd()

Convert calendar time to Julian day. Returns UTC time in Julian days (float).

to_zone(gmtoff=None)

Convert UTC calendar time to local calendar time.

Param: gmtoff - local seconds offset from UTC (integer -43200 to 43200).
if set to None, the time module offset value is used for current location

Returns object of type zonedate representing local time.

lsl.astro.date_to_zonedate(date, gmtoff)

Convert UTC calendar time to local calendar time.

Param: date - A date object representing UTC time. Param: gmtoff - Seconds offset from UTC (integer -43200 to 43200).

Returns object of type zonedate representing local time.

lsl.astro.deg_to_dms(degrees)

Convert angles float degrees to degrees, minutes, seconds.

Param: degrees - Angle in degrees (float).

Returns object of type dms representing angle.

lsl.astro.deg_to_hms(degrees)

Convert angles float degrees to hours, minutes, seconds.

Param: degrees - Angle in degrees (float).

Returns object of type hms representing angle.

lsl.astro.deg_to_rad(degrees)

Convert degres to radians.

Param: degrees - Angle in degrees (float).

Returns angle in radians (float).

lsl.astro.deg_to_sec(degrees)

Convert longitude degrees into time seconds.

Param: degrees - longitude (float degrees)

Returns: Seconds (float) offset in time for longitude.

lsl.astro.dir_cos(posn)

Get direction cosines from azimuth and zenith angles. This function calculates the cosine values based on the LWA coordinate system: l = unit vector in E direction (azimuth = 90) m = unit vector in N direction (azimuth = 0) n = unit vector in zenith direction (zenith = 0, altitude = 90)

Param: posn - object of type hrz_posn giving local position

Returns a tuple (l,m,n) of float values for the direction cosines.

class lsl.astro.dms(neg=False, degrees=0, minutes=0, seconds=0.0)

Represents angles in degrees, minutes, seconds.

Public members:
neg - True if measured west of GM, south of EQ
False if measured east of GM, north of EQ.

degrees - Angle degrees (integer). minutes - Angle minutes (integer). seconds - Angle seconds (float).

to_deg()

Convert angles degrees, minutes, seconds to float degrees. Returns angle in degrees (float).

to_hms()

Convert angles degrees, minutes seconds to hours, minutes, seconds. Returns: object of type hms representing angle.

lsl.astro.dms_to_deg(dms)

Convert angles degrees, minutes, seconds to float degrees.

Param: dms - Object of type dms representing angle.

Returns angle in degrees (float).

lsl.astro.dms_to_rad(dms)

Convert angles degrees, minutes, seconds to radians.

Param: dms - Object of type dms representing angle.

Returns angle in radians (float).

class lsl.astro.ecl_posn(lng=0.0, lat=0.0)

Represents position as ecliptic longitude and latitude.

Public members:
lng - Position longitude coordinate (float degrees). lat - Position latitude coordinate (float degrees).
Members may also be accessed by subscript:
ecl_posn[0] = lng ecl_posn[1] = lat
format()

Return a tuple (lng, lat) where lng is an dms object and lat is a dms object representing longitude and latitude position coordinates.

to_equ(jD)

Get equatorial coordinates from ecliptical coordinates for a given time.

Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

class lsl.astro.equ_posn(ra=0.0, dec=0.0)

Represents equatoral/celestial position coordinates.

Public members:
ra - Position right ascension angle (float degrees). dec - Position declination angle (float degrees).
Members may also be accessed by subscript:
equ_posn[0] = ra equ_posn[1] = dec
angular_separation(posn)

Get angular separation from equatorial position.

Param: posn - Object of type equ_posn representing body 2 position.

Returns angular separation in degrees (float).

format()

Return a tuple (ra, dec) where ra is an hms object and dec is a dms object representing ra and dec position coordinates.

precess(jD)

Get position of celestial object accounting for precession. The equatorial coordinates should be for the J2000 epoch.

Param: jD - UTC Julian day (float) to measure position.

Returns: Adjusted equatorial position of object as type equ_posn.

to_ecl(jD)

Get ecliptical coordinates from equatorial coordinates.

Param: jD - UTC Julian day (float).

Returns object of type lnlat_posn representing eclipitcal position.

to_gal(jD)

Get J2000 galactic coordinates from apparent equatorial coordinates.

Param: jD - UTC Julian day to get position.

Returns object of type gal_posn representing object’s galactic position.

to_hrz(observer, jD)

Get local horizontal coordinates from equatorial/celestial coordinates.

Param: observer - Object of type lnlat_posn representing observer position. Param: jD - UTC Julian day (float).

Returns object of type hrz_posn representing local position.

class lsl.astro.gal_posn(l=0.0, b=0.0)

Represents galactic position coordinates.

Public members:
l - Position longitude angle (float degrees). b - Position latitude angle (float degrees).
Members may also be accessed by subscript:
gal_posn[0] = l gal_posn[1] = b
format()

Return a tuple (lng, lat) where lng is an dms object and lat is a dms object representing galactic longitude and latitude position coordinates.

to_equ(jD)

Get apparent equatorial coordinates from J2000 galactic coordinates.

Param: jD - UTC Julian day to get position.

Returns object of type equ_posn representing object’s apparent equatorial position.

class lsl.astro.geo_posn(lng=0.0, lat=0.0, elv=0.0)

Class to represent geographical position in terms of longitude, lattitude, and elevation. This is a set of geodetic coordinates based on the WGS84 model.

Public members:
lng - longitude (float) lat - latitude (float) elv - elevation (float)
Members may also be accessed by subscript:
geo_posn[0] = lng geo_posn[1] = lat geo_posn[2] = elv
lsl.astro.get_angular_separation(posn1, posn2)

Get angular separation from equatorial positions.

Param: posn1 - Object of type equ_posn representing body 1 position. Param: posn2 - Object of type equ_posn representing body 2 position.

Returns angular separation in degrees (float).

lsl.astro.get_apparent_posn(mean_position, jD, proper_motion=None)

Get apparent position of celestial object accounting for precession, nutation, aberration, and optionally proper motion.

Param: mean_position - J2000 equatorial mean position of object as type
equ_posn.

Param: jD - UTC Julian day (float) to measure position. Param: proper_motion - object of type equ_posn giving object’s proper motion

(optional).

Returns: Apparent equatorial position of object as type equ_posn.

lsl.astro.get_apparent_sidereal_time(jD)

Get apparent sidereal time from Julian day.

Param: jD - UTC Julian day (float).

Returns GM apparent sidereal time (float hours).

From: http://aa.usno.navy.mil/faq/docs/GAST.php

lsl.astro.get_date(jD)

Convert Julian day to calendar time.

Param: jD - UTC time in Julian days (float).

Returns object of type date representing UTC time.

lsl.astro.get_date_from_sys()

Gets calendar time from system clock.

Returns object of type date representing UTC time.

lsl.astro.get_day_of_week(date)

Gets day of week from calendar time.

Param: date - Object of type date representing UTC time.

Returns day of week (0 = Sunday, 6 = Saturday).

lsl.astro.get_ecl_from_equ(object_, jD)

Get ecliptical coordinates from equatorial coordinates for a given time.

Param: object_ - Object of type equ_posn representing equatorial position. Param: jD - UTC Julian day (float).

Returns object of type ecl_posn representing ecliptic position.

lsl.astro.get_ecl_from_rect(rect)

Get ecliptical coordinates from rectangular coordinates.

Param: rect - Object of type rect_posn representing position.

Returns object of type lnlat_posn representing ecliptical position.

lsl.astro.get_equ2000_from_gal(object_)

Get J2000 equatorial coordinates from galactic coordinates.

Param: object_ - Object of type gal_posn representing galactic position.

Returns object of type equ_posn representing J2000 equatorial position.

lsl.astro.get_equ_aber(mean_position, jD)

Get position of celestial object accounting for aberration.

Param: mean_position - J2000 equatorial mean position of object as type
equ_posn.

Param: jD - UTC Julian day (float) to measure aberration.

Returns: Adjusted equatorial position of object as type equ_posn.

Based on the libnova ln_get_equ_aber() function.

lsl.astro.get_equ_from_ecl(object_, jD)

Get equatorial coordinates from ecliptical coordinates for a given time.

Param: object_ - Object of type lnlat_posn representing ecliptic position. Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

lsl.astro.get_equ_from_gal(object_)

Get B1950 equatorial coordinates from galactic coordinates.

Param: object_ - Object of type gal_posn representing galactic position.

Returns object of type equ_posn representing B1950 equatorial position.

lsl.astro.get_equ_from_hrz(object_, observer, jD)

Get equatorial/celestial coordinates from local horizontal coordinates.

Param: object_ - Object of type hrz_posn representing horizontal position. Param: observer - Object of type lnlat_posn representing observer position. Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

lsl.astro.get_equ_from_rect(posn)

Transform rectangular coordinates to equatorial coordinates.

Param: posn - Object of type rect_posn giving position.

Returns: Object of type equ_posn giving equatorial coordinates.

lsl.astro.get_equ_nut(position, jD)

Get the position of a celesital object accounting for nutation.

Param: mean_position - Equatorial position of object as type
equ_posn.

Param: jD - UTC Julian day (float) to measure nutation.

Returns: Adjusted equatorial position of object as type equ_posn.

Based on the AstroIDL co_nutate.pro procedure

lsl.astro.get_equ_pm(mean_position, proper_motion, jD)

Adjusts equatorial position of a stellar object accouting for proper motion.

Param: mean_position - J2000 equatorial mean position of object as type equ_posn. Param: proper_motion - Object of type equ_posn giving object’s proper motion

(units are deg/year).

Param: jD - UTC Julian day (float) to measure position.

Returns: Adjusted equatorial position of object as type equ_posn.

Based on pm.f, dcs2c.f, and dcc2s.f from SLALIB.

lsl.astro.get_equ_prec(mean_position, jD)

Get position of celestial object accounting for precession. Only works for converting to and from J2000 epoch.

Param: mean_position - J2000 equatorial mean position of object as type equ_posn. Param: jD - UTC Julian day (float) to measure position.

Returns: Adjusted equatorial position of object as type equ_posn.

lsl.astro.get_equ_prec2(mean_position, fromJD, toJD)

Get position of celestial object accounting for precession.

Param: mean_position - equatorial first position of object as type equ_posn. Param: fromJD - UTC Julian day (float) of first time. Param: toJD - UTC Julian day (float) of second time.

Returns: Equatorial position of object as type equ_posn converted from
time 1 to time 2.
lsl.astro.get_gal_from_equ(object_)

Get galactic coordinates from B1950 equatorial coordinates.

Param: object_ - Object of type equ_posn representing B1950 equatorial
position.

Returns object of type gal_posn representing galactic position.

lsl.astro.get_gal_from_equ2000(object_)

Get galactic coordinates from J2000 equatorial coordinates.

Param: object_ - Object of type equ_posn representing J2000 equatorial
position.

Returns object of type gal_posn representing galactic position.

lsl.astro.get_geo_from_rect(posn)

Transform ECEF rectangular coordinates to geographical coordinates. Adapoted from “Satellite Orbits”, Montenbruck and Gill 2005, 5.85 - 5.88. Also see gpstk ECEF::asGeodetic() method.

Param: posn - object of type rect_posn giving position.

Returns: object of type geo_posn giving geographical coordinates.

lsl.astro.get_gmtoff()

Get local UTC offset based on Python time module and system info.

lsl.astro.get_hrz_from_equ(object_, observer, jD)

Get local horizontal coordinates from equatorial/celestial coordinates.

Param: object_ - Object of type equ_posn representing celestial position. Param: observer - Object of type lnlat_posn representing observer position. Param: jD - UTC Julian day (float).

Returns object of type hrz_posn representing local position.

lsl.astro.get_julian_day(date)

Convert calendar time to Julian day.

Param: date - Object of type date representing UTC time.

Returns UTC time in Julian days (float).

lsl.astro.get_julian_from_sys()

Returns UTC Julian day (float) from system clock.

lsl.astro.get_julian_from_timet(time_)

Gets Julian day from Unix time.

Param: time_ - Unix timet in seconds (integer)

Returns UTC Julian day (float).

lsl.astro.get_julian_local_date(zonedate)

Convert local calendar time to Julian day.

Param: zonedate - Object of type zonedate representing local time.

Returns UTC time in Julian days (float).

lsl.astro.get_jupiter_equ_coords(jD)

Get Jupiter’s apparent equatorial coordinates from Julian day. Accounts for aberration and precession, but not nutation.

Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

lsl.astro.get_jupiter_rst(jD, observer)

Get Jupiter’s rise, transit, set times from Julian day.

Param: jD - UTC Julian day (float). Param: observer - Object of type lnlat_posn representing observer position.

Returns Object of type rst_time represeting UTC ephemeris times,
or None if the object is circumpolar.
lsl.astro.get_local_sidereal_time(lng, jD)

Get apparent local sidereal time from Julian day.

Param: lng - longitude degrees (float), E = positive, W = negative Param: jD - UTC Julian day (float).

Returns: Local mean sidereal time (float hours).

lsl.astro.get_lunar_equ_coords(jD)

Get the Moon’s apparent equatorial coordinates from Julian day. Accounts for aberration and precession, but not nutation.

Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

lsl.astro.get_lunar_rst(jD, observer)

Get the Moon’s rise, transit, set times from Julian day.

Param: jD - UTC Julian day (float). Param: observer - Object of type lnlat_posn representing observer position.

Returns Object of type rst_time represeting UTC ephemeris times,
or None if the object is circumpolar.
lsl.astro.get_mars_equ_coords(jD)

Get Mars’ apparent equatorial coordinates from Julian day. Accounts for aberration and precession, but not nutation.

Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

lsl.astro.get_mars_rst(jD, observer)

Get Mars’ rise, transit, set times from Julian day.

Param: jD - UTC Julian day (float). Param: observer - Object of type lnlat_posn representing observer position.

Returns Object of type rst_time represeting UTC ephemeris times,
or None if the object is circumpolar.
lsl.astro.get_mean_sidereal_time(jD)

Get mean sidereal time from Julian day.

Param: jD - UTC Julian day (float).

Returns GM mean sidereal time (float hours).

From: http://aa.usno.navy.mil/faq/docs/GAST.php

lsl.astro.get_nutation(jD)

Get nutation corrections for a given time.

Param: jD - UTC Julian day (float) to measure nutation.

Returns: Nutation corrections as object of type nutation.

Based on the nutate.pro and co_nutate.pro from the AstroIDL library.

lsl.astro.get_object_rst(jD, observer, object_)

Get rise, set, and transit times of a celstial object.

Param: jD - UTC Julian day (float) target time. Param: observer - object of type lnlat_posn giving observer position Param: object_ - object of type equ_posn giving target equatorial position

Returns: Object of type rst_time giving object’s ephemeris UTC times,
or None if the object is circumpolar.
lsl.astro.get_precession(jD1, pos, jD2)

Caculate precession of equatorial coordinates from one epoch to another.

Param: jD1 - UTC Julian day of epoch 1. Param: pos - object of type equ_posn giving epoch 1 position Param: jD2 - UTC Julian day of epoch 2.

Returns: object of type equ_posn giving epoch 2 position.

lsl.astro.get_rect_from_equ(posn)

Transform equatorial coordinates to rectangular coordinates.

Param: posn - Object of type equ_posn giving position.

Returns: Object of type rect_posn giving rectangular coordinates (normallized to 1).

lsl.astro.get_rect_from_geo(posn)

Transform geographical coordinates to ECEF rectangular coordinates. Adopted from “Satellite Orbits”, Montenbruck and Gill 2005, 5.83 - 5.84. Also see gpstk Geodetic::asECEF() method.

Param: posn - object of type geo_posn giving geographical coordinates.

Returns: object of type rect_posn giving ECEF position.

lsl.astro.get_rel_posn_angle(posn1, posn2)

Get relative position angle from equatorial positions.

Param: posn1 - Object of type equ_posn representing body 1 position. Param: posn2 - Object of type equ_posn representing body 2 position.

Returns position angle in degrees (float).

Based on dpav.f from SLALIB.

lsl.astro.get_saturn_equ_coords(jD)

Get Saturn’s apparent equatorial coordinates from Julian day. Accounts for aberration and precession, but not nutation.

Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

lsl.astro.get_saturn_rst(jD, observer)

Get Saturn’s rise, transit, set times from Julian day.

Param: jD - UTC Julian day (float). Param: observer - Object of type lnlat_posn representing observer position.

Returns Object of type rst_time represeting UTC ephemeris times,
or None if the object is circumpolar.
lsl.astro.get_solar_equ_coords(jD)

Get Sun’s apparent equatorial coordinates from Julian day. Accounts for aberration and precession, and nutation.

Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

lsl.astro.get_solar_rst(jD, observer)

Get Sun’s rise, transit, set times from Julian day.

Param: jD - UTC Julian day (float). Param: observer - Object of type lnlat_posn representing observer position.

Returns Object of type rst_time represeting UTC ephemeris times,
or None if the object is circumpolar..
lsl.astro.get_tai_from_sys()

Return the current time taken from the system clock as a TAI MJD (float).

lsl.astro.get_timet_from_julian(jD)

Gets Unix time from Julian day.

Param: jD - UTC Julian day (float).

Returns Unix timet in seconds (integer).

lsl.astro.get_venus_equ_coords(jD)

Get Venus’ apparent equatorial coordinates from Julian day. Accounts for aberration and precession, but not nutation.

Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

lsl.astro.get_venus_rst(jD, observer)

Get Venus’ rise, transit, set times from Julian day.

Param: jD - UTC Julian day (float). Param: observer - Object of type lnlat_posn representing observer position.

Returns Object of type rst_time represeting UTC ephemeris times,
or None if the object is circumpolar.
class lsl.astro.hms(hours=0, minutes=0, seconds=0.0)

Represents times/angles in hours, minutes, seconds.

Public members:
hours - Angle/time hours (integer). minutes - Angle/time minutes (integer). seconds - Angle/time seconds (float).
to_deg()

Convert angles hours, minutes, seconds to float degrees. Returns angle in degrees (float).

to_dms()

Convert angle hours, minutes, seconds to degrees, minutes, seconds. Returns: object of type dms representing angle.

to_sec()

Convert angle hours, minutes, seconds to seconds. Returns: time/angle as seconds.

lsl.astro.hms_to_deg(hms)

Convert angles hours, minutes, seconds to float degrees.

Param: hms - Object of type hms representing angle.

Returns angle in degrees (float).

lsl.astro.hms_to_rad(hms)

Convert angles hours, minutes, seconds to float radians.

Param: hms - Object of type hms representing angle.

Returns angle in radians (float).

lsl.astro.hms_to_sec(hms)

Convert hours, minutes, seconds to seconds.

Param: hms - object of type hms representing time/angle.

Returns: Seconds (float) offset of time/angle.

class lsl.astro.hrz_posn(az=0.0, alt=0.0)

Represents horizontal local position coordinates. LWA measures azimuth angle clockwise from north to east, with due north equal to 0 degrees. Also, method for using zenith angle instead of altitude angle have been added.

Public members:
az - Position azimuth angle (float degrees). alt - Position altitude angle (float degrees)
Members may also be accessed by subscript:
hrz_posn[0] = az hrz_posn[1] = alt
dir_cos()

Get direction cosines from horizontal coordinates.

Returns: A tuple (l,m,n) of float values for the direction cosines.
l = unit vector in E direction (azimuth = 90) m = unit vector in N direction (azimuth = 0) n = unit vector in zenith direction (zenith = 0, altitude = 90)
to_equ(observer, jD)

Get equatorial/celestial coordinates from local horizontal coordinates.

Param: observer - Object of type lnlat_posn representing observer position. Param: jD - UTC Julian day (float).

Returns object of type equ_posn representing equatorial position.

zen(value=None)

If value is None, returns position zenith angle (float degrees [0, 180]) Otherwise, sets the altitude according to the zenith angle value.

lsl.astro.hrz_to_nswe(pos)

Get cardinal/ordinal azimuth direction.

Param: pos - Object of type hrz_posn giving local position.

Returns string giving direction.

lsl.astro.jd_to_mjd(jd)

Get modified julian day value from julian day value.

Param: jd - julian day (should be >= 2400000.5)

Returns: Modified julian day.

lsl.astro.jd_to_sec(jD)

Convert Julian days into seconds.

Param: jD - Julian days (float).

Returns: Seconds as a float.

lsl.astro.leap_secs(utcJD)

Get the number of leap seconds for given UTC time value.

Param: utcJD - The UTC JD time.
This should be greater than 2441317.5 (1972 JAN 1).

Returns: The number of leap seconds (float) for the UTC time.

class lsl.astro.lnlat_posn(lng=0.0, lat=0.0)

Represents position coordinates in latitude and longitude. When representing a geographical location, the longitude is negative when measured west of GM and positive is measured east of GM.

Public members:
lng - Position longitude coordinate (float degrees). lat - Position latitude coordinate (float degrees).
Members may also be accessed by subscript:
lnlat_posn[0] = lng lnlat_posn[1] = lat
format()

Return a tuple (lng, lat) where lng is an dms object and lat is a dms object representing longitude and latitude position coordinates.

lsl.astro.mjd_to_jd(mjd)

Get julian day value from modified julian day value.

Param: mjd - modified julian day (should be >= 0.0)

Returns: Julian day.

class lsl.astro.nutation(longitude=0.0, obliquity=0.0, ecliptic=0.0)

Provides nutation information in longitude and obliquity.

Public members:
longitude - Nutation in longitude (float degrees). obliquity - Nutation in ecliptic obliquity (float degrees). ecliptic - Obliquity of the ecliptic (float degrees).
format()

Return a tuple (lng, obl, ecl) where lng is an dms object, obl is a dms object, and ecl is a dms object representing nutation in longitude and obliquity, and obliquity of the ecliptic.

lsl.astro.rad_to_deg(radians)

Convert radians to degrees.

Param: radians - Angle in radians (float).

Returns angle in degrees (float).

lsl.astro.rad_to_dms(radians)

Convert angles float radians to degrees, minutes, seconds.

Param: radians - Angle in radians (float).

Returns object of type dms representing angle.

lsl.astro.rad_to_hms(radians)

Convert angles float radians to hours, minutes, seconds.

Param: radians - Angle in radians (float).

Returns object of type hms representing angle.

lsl.astro.range_degrees(degrees)

Put angle into range [0, 360].

Param: degrees - large angle (float degrees)

Returns: angle in range (float degrees)

lsl.astro.range_hours(hours)

Put an hour time value into the correct range [0.0, 24.0].

class lsl.astro.rect_posn(X=0.0, Y=0.0, Z=0.0)

Represents rectangular/Cartesian position coordinates.

Public members:
X - Position X coordinate (float). Y - Position Y coordinate (float). Z - Position Z coordinate (float).
Members may also be accessed by subscript:
rect_posn[0] = X rect_posn[1] = Y rect_posn[2] = Z
class lsl.astro.rst_time(rise=None, set=None, transit=None)

Represents ephemeris rist, set, and transit times.

Public members:
rise - Rise time in UTC Julian days (float). set - Set time in UTC Julian days (float). transit - Transit time in UTC Julian days (float).
format()

Return a tuple (rise, set, transit) where all three are date objects representing the ephemeris times.

lsl.astro.sec_to_jd(secs)

Convert seconds into julian days.

Param: secs - seconds (float)

Returns: Julian days as a float.

lsl.astro.tai_to_tt(taiJD)

Get the TT JD time value for a given TAI JD time value.

Param: taiJD - The TAI JD time (float).

Returns: The TT JD value (float).

lsl.astro.tai_to_utc(taiJD)

Get the UTC JD time value for a given TAI JD time value.

Param: taiJD - The TAI JD time (float).
This should be greater than 2441317.5 (1972 JAN 1).

Returns: The UTC JD value (float).

lsl.astro.taimjd_to_unix(taiMJD)

Get UNIX time value for a given TAI MJDvalue.

Param: taiMJD - The TAI MJD time (float).

Returns: The UNIX time

lsl.astro.taimjd_to_utcjd(taiMJD)

Get the UTC JD time value for a given TAI MJD value.

Param: mjdTAI - The TAI MJD time (float).

Returns: The UTC JD value (float).

lsl.astro.tt_to_tai(ttJD)

Get the TAI JD time value for a given TT JD time value.

Param: ttJD - The TT JD time (float).

Returns: The TAI JD value (float).

lsl.astro.tt_to_tdb(ttJD)

Get the TDB JD time value for a given TT JD time value. Adopted from “Astronomical Almanac Supplement”, Seidelmann 1992, 2.222-1.

Param: ttJD - The TT JD time (float).

Returns: The TDB JD value (float).

lsl.astro.tt_to_utc(ttJD)

Get the UTC JD time value for a given TT JD time value.

Param: ttJD - The TT JD time (float).

Returns: The UTC JD value (float).

lsl.astro.unix_to_taimjd(unixTime)

Get the TAI MJD time value for a given UNIX time value.

Param: unixTime - the UNIX time (int/float)

Returns: The TAI MJD value.

lsl.astro.unix_to_utcjd(unixTime)

Get the UTC JD time value for a given UNIX time value.

Param: unixTime - the UNIX time (int/float)

Returns: The UTC JD value.

lsl.astro.utc_to_tai(utcJD)

Get the TAI JD time value for a given UTC JD time value.

Param: utcJD - The UTC JD time (float).
This should be greater than 2441317.5 (1972 JAN 1).

Returns: The TAI JD value (float).

lsl.astro.utc_to_tt(utcJD)

Get the TT JD time value for a given UTC JD time value.

Param: utcJD - The UTC JD time (float).

Returns: The TT JD value (float).

lsl.astro.utcjd_to_taimjd(utcJD)

Get the TAI MJD time value for a given UTC JD value.

Param: utcJD - The UTC JD time (float).

Returns: The TAI MJD value.

lsl.astro.utcjd_to_unix(utcJD)

Get UNIX time value for a given UTC JD value.

Param: utcJD - The UTC JD time (float).

Returns: The UNIX time

class lsl.astro.zonedate(years=2000, months=1, days=1, hours=0, minutes=0, seconds=0.0, gmtoff=0)

Represents local time in calendar units.

Public members:
years - Date years (integer). months - Date months (integer). days - Date days (integer). hours - Date hours (integer). minutes - Date minutes (integer). seconds - Date seconds (float). gmtoff - Seconds offset from GM (integer).
to_date()

Convert local calendar time to UTC calendar time. Returns object of type date representing UTC time.

to_jd()

Convert calendar time to Julian day. Returns UTC time in Julian days (float).

lsl.astro.zonedate_to_date(zonedate)

Convert local calendar time to UTC calendar time.

Param: zonedate - Object of type zonedate representing local time.

Returns object of type date representing UTC time.

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