Astronomical Utilities¶

New in version 0.2.

Astronomical utility functions and classes based on libnova library.

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.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.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(target, jD)¶

Get ecliptical coordinates from equatorial coordinates for a given time.

Param: target - 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(target)¶

Get J2000 equatorial coordinates from galactic coordinates.

Param: target - 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(target, jD)¶

Get equatorial coordinates from ecliptical coordinates for a given time.

Param: target - 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(target)¶

Get B1950 equatorial coordinates from galactic coordinates.

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

Returns object of type equ_posn representing B1950 equatorial position.

lsl.astro.get_equ_from_hrz(target, observer, jD)¶

Get equatorial/celestial coordinates from local horizontal coordinates.

Param: target - 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(target)¶

Get galactic coordinates from B1950 equatorial coordinates.

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

Returns object of type gal_posn representing galactic position.

lsl.astro.get_gal_from_equ2000(target)¶

Get galactic coordinates from J2000 equatorial coordinates.

Param: target - 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(target, observer, jD)¶

Get local horizontal coordinates from equatorial/celestial coordinates.

Param: target - 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(timet)¶

Gets Julian day from Unix time.

Param: timet - 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, target)¶

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: target - 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.

Astronomical Utilities¶

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