Procedures for coordinates. More...

Functions/Subroutines
subroutine	hc_spher_2_gc_rect (l, b, r, l0, b0, r0, x, y, z)
	Compute the geocentric rectangular coordinates of a planet, from its and the Earth's heliocentric spherical position.

subroutine	ecl_spher_2_eq_rect (l, b, r, eps, x, y, z)
	Convert spherical, ecliptical coordinates to rectangular, equatorial coordinates of an object - both geocentric.

subroutine	calcsunxyz (t1, l0, b0, r0, x, y, z)
	Compute the geocentric equatorial rectangular coordinates of the Sun, from Earth's heliocentric, spherical position.

subroutine	precess_xyz (jd1, jd2, x, y, z)
	Compute the precession of the equinoxes in rectangular coordinates, from jd1 to jd2.

subroutine	precess_eq (jd1, jd2, a1, d1)
	Compute the precession of the equinoxes in equatorial coordinates, from jd1 to jd2.

subroutine	precess_eq_yr (yr1, yr2, a1, d1)
	Compute the precession of the equinoxes in equatorial coordinates, from yr1 to yr2.

subroutine	precess_ecl (jd1, jd2, l, b)
	Compute the precession of the equinoxes in geocentric ecliptical coordinates.

subroutine	precess_orb (jd1, jd2, i, o1, o2)
	Compute the precession of the equinoxes in orbital elements.

subroutine	rect_2_spher (x, y, z, l, b, r)
	Convert rectangular coordinates x,y,z to spherical coordinates l,b,r.

subroutine	aberration_ecl (t, l0, l, b)
	Correct ecliptic longitude and latitiude for annual aberration.

subroutine	aberration_eq (jd, ra, dec, dra, ddec, eps0)
	Correct equatorial coordinates for annual aberration - moderate accuracy, use for stars.

subroutine	fk5 (t, l, b)
	Convert coordinates to the FK5 system.

subroutine	ecl_2_eq (l, b, eps, ra, dec)
	Convert (geocentric) spherical ecliptical coordinates l,b (and eps) to spherical equatorial coordinates RA, Dec.

subroutine	eq_2_ecl (ra, dec, eps, l, b)
	Convert (geocentric) spherical equatorial coordinates RA, Dec (and eps) to spherical ecliptical coordinates l,b.

subroutine	eq2horiz (ra, dec, agst, hh, az, alt, lat, lon)
	Convert spherical equatorial coordinates (RA, dec, agst) to spherical horizontal coordinates (hh, az, alt)

subroutine	horiz2eq (az, alt, agst, hh, ra, dec, lat, lon)
	Convert spherical horizontal coordinates (az, alt, agst) to spherical equatorial coordinates (hh, RA, dec)

subroutine	eq2gal (ra, dec, l, b)
	Convert spherical equatorial coordinates (RA, dec) to spherical galactic coordinates (l,b), for J2000.0!!!

subroutine	gal2eq (l, b, ra, dec)
	Convert spherical galactic coordinates (l,b) to spherical equatorial coordinates (RA, dec), for J2000.0!!!

subroutine	geoc2topoc_ecl (gcl, gcb, gcr, gcs, eps, lst, tcl, tcb, tcs, lat, hgt)
	Convert spherical ecliptical coordinates from the geocentric to the topocentric system.

subroutine	geoc2topoc_eq (gcra, gcd, gcr, gch, tcra, tcd, lat, hgt)
	Convert geocentric equatorial coordinates to topocentric.

real(double) function	refract (alt, press, temp)
	Compute the atmospheric refraction for a given true altitude. You should add the result to the uncorrected altitude in order to obtain the observed altitude. Return 0 if alt + refract < -0.3°.

real function	refract_sp (alt, press, temp)
	Compute the atmospheric refraction for a given true altitude, using single-precision values. This is a wrapper for refract().

real(double) function	atmospheric_refraction (alt0, h0, lat0, t0, p0, rh, lam, dtdh, eps)
	Compute the atmospheric refraction of light for a given true altitude. Return 0 for alt<-0.9°. This is a wrapper for aref(), which does the opposite (compute refraction for an apparent zenith angle). This is an expensive way to go about(!)

real(double) function	atmospheric_refraction_apparent (alt0, h0, ph, t0, p0, rh, lam, dtdh, eps)
	Compute the atmospheric refraction of light for a given apparent (observed) altitude of a celestial object and a given observer. Note that you will usually want to use the true altitude as input instead. The method is based on N.A.O Technical Notes 59 and 63 and a paper by Standish and Auer 'Astronomical Refraction: Computational Method for all Zenith Angles'. Return 0 if alt<-1.102°.

real(double) function	aref (z0, h0, ph, t0, p0, rh, lam, dtdh, eps)
	Compute the atmospheric refraction of light for a given apparent (observed) zenith angle. The method is based on N.A.O Technical Notes 59 and 63 and a paper by Standish and Auer 'Astronomical Refraction: Computational Method for all Zenith Angles'. Return 0 if z0>91.102°.

real(double) function	refi (r, n, dndr)
	The refraction integrand for atmospheric_refraction_apparent()

subroutine	troposphere_model (r0, t0, a, r, t, n, dndr)
	Troposphere model for atmospheric_refraction_apparent()

subroutine	stratosphere_model (rt, tt, nt, a, r, n, dndr)
	Stratosphere model for atmospheric_refraction_apparent()

Detailed Description

Procedures for coordinates.

Function/Subroutine Documentation

◆ aberration_ecl()

subroutine thesky_coordinates::aberration_ecl	(	real(double), intent(in)	t,
		real(double), intent(in)	l0,
		real(double), intent(inout)	l,
		real(double), intent(inout)	b )

Correct ecliptic longitude and latitiude for annual aberration.

Parameters

t	Dynamical time in Julian Millennia since 2000.0
l0	Earth longitude (rad)
l	Longitude of the object (rad, I/O) (output)
b	Latitude of the object (rad, I/O) (output)

See also: Meeus, Astronomical Algorithms, 1998, Ch.23

Definition at line 426 of file coordinates.f90.

Referenced by thesky_planets::planet_position().

◆ aberration_eq()

subroutine thesky_coordinates::aberration_eq	(	real(double), intent(in)	jd,
		real(double), intent(in)	ra,
		real(double), intent(in)	dec,
		real(double), intent(out)	dra,
		real(double), intent(out)	ddec,
		real(double), intent(in), optional	eps0 )

Correct equatorial coordinates for annual aberration - moderate accuracy, use for stars.

Parameters

jd	Julian day of epoch
ra	Right ascension of the object (rad)
dec	Declination of the object (rad)
dra	Correction in right ascension due to aberration (rad) (output)
ddec	Correction in declination due to aberration(rad) (output)
eps0	The mean obliquity of the ecliptic

See also: Meeus, Astronomical Algorithms, 1998, Ch.23

Definition at line 470 of file coordinates.f90.

References thesky_nutation::nutation().

Referenced by thesky_stars::calcstars().

Here is the call graph for this function:

◆ aref()

real(double) function thesky_coordinates::aref	(	real(double), intent(in)	z0,
		real(double), intent(in)	h0,
		real(double), intent(in)	ph,
		real(double), intent(in)	t0,
		real(double), intent(in)	p0,
		real(double), intent(in)	rh,
		real(double), intent(in)	lam,
		real(double), intent(in)	dtdh,
		real(double), intent(in)	eps )

Compute the atmospheric refraction of light for a given apparent (observed) zenith angle. The method is based on N.A.O Technical Notes 59 and 63 and a paper by Standish and Auer 'Astronomical Refraction: Computational Method for all Zenith Angles'. Return 0 if z0>91.102°.

Parameters

z0	The observed zenith distance of the object in degrees(!)
h0	The height of the observer above sea level in metres
ph	The latitude of the observer in degrees(!)
t0	The temperature at the observer in Kelvin
p0	The pressure at the observer in millibars
rh	The relative humidity at the observer as a fraction (0-1)
lam	The wavelength of the light at the observer in micrometres
dTdh	The temperature lapse rate dT/dh in Kelvin/metre in the troposphere; the absolute value is used
eps	The desired precision in arcseconds(!)

Return values

aref	The refraction at the observer in degrees(!)

See also: Hohenkerk & Sinclair, HMNAO technical note 63 (1985)

Definition at line 1277 of file coordinates.f90.

References aref(), and atmospheric_refraction_apparent().

Referenced by aref(), and atmospheric_refraction().

Here is the call graph for this function:

◆ atmospheric_refraction()

real(double) function thesky_coordinates::atmospheric_refraction	(	real(double), intent(in)	alt0,
		real(double), intent(in)	h0,
		real(double), intent(in)	lat0,
		real(double), intent(in)	t0,
		real(double), intent(in)	p0,
		real(double), intent(in)	rh,
		real(double), intent(in)	lam,
		real(double), intent(in)	dtdh,
		real(double), intent(in)	eps )

Compute the atmospheric refraction of light for a given true altitude. Return 0 for alt<-0.9°. This is a wrapper for aref(), which does the opposite (compute refraction for an apparent zenith angle). This is an expensive way to go about(!)

Parameters

alt0	The true (theoretical, computed) altitude of the object in radians
h0	The height of the observer above sea level in metres
lat0	The latitude of the observer in radians
t0	The temperature at the observer in degrees Celsius (e.g. 10)
p0	The pressure at the observer in millibars (e.g. 1010)
rh	The relative humidity at the observer in percent (e.g. 50)
lam	The wavelength of the light at the observer in nanometres (e.g. 550)
dTdh	The temperature lapse rate dT/dh in Kelvin/metre in the troposphere (only the absolute value is used; e.g. 0.0065)
eps	The desired precision in arcseconds (e.g. 1.d-3)

Return values

atmospheric_refraction The refraction at the observer in radians

Todo: Adapt aref() to compute the integral in the other direction for a direct method(?)

Definition at line 1003 of file coordinates.f90.

References aref(), and atmospheric_refraction().

Referenced by atmospheric_refraction().

Here is the call graph for this function:

◆ atmospheric_refraction_apparent()

real(double) function thesky_coordinates::atmospheric_refraction_apparent	(	real(double), intent(in)	alt0,
		real(double), intent(in)	h0,
		real(double), intent(in)	ph,
		real(double), intent(in), optional	t0,
		real(double), intent(in), optional	p0,
		real(double), intent(in), optional	rh,
		real(double), intent(in), optional	lam,
		real(double), intent(in), optional	dtdh,
		real(double), intent(in), optional	eps )

Compute the atmospheric refraction of light for a given apparent (observed) altitude of a celestial object and a given observer. Note that you will usually want to use the true altitude as input instead. The method is based on N.A.O Technical Notes 59 and 63 and a paper by Standish and Auer 'Astronomical Refraction: Computational Method for all Zenith Angles'. Return 0 if alt<-1.102°.

Parameters

alt0	The observed (apparent) altitude of the object (rad).
h0	The height of the observer above sea level (metres).
ph	The latitude of the observer (rad).
t0	The temperature at the observer's site; optional, default 10 (°C).
p0	The air pressure at the observer's site; optional, default: 1010 (mbar).
rh	The relative humidity at the observer's site; optional, default: 0.5 (fraction: 0-1).
lam	The wavelength of the light; optional, default: 550 (nm).
dTdh	The temperature gradient dT/dh in the troposphere; the absolute value is used; optional, default: 6.5e-3 (Kelvin/metre).
eps	The desired precision; optional, default: 1e-4; don't make this smaller than ~1e-8 (rad).

Return values

atmospheric_refraction_apparent The refraction at the observer (rad).

See also: Hohenkerk & Sinclair, HMNAO technical note 63 (1985).

Definition at line 1064 of file coordinates.f90.

References atmospheric_refraction_apparent(), refi(), stratosphere_model(), and troposphere_model().

Referenced by aref(), and atmospheric_refraction_apparent().

Here is the call graph for this function:

◆ calcsunxyz()

subroutine thesky_coordinates::calcsunxyz	(	real(double), intent(in)	t1,
		real(double), intent(in)	l0,
		real(double), intent(in)	b0,
		real(double), intent(in)	r0,
		real(double), intent(out)	x,
		real(double), intent(out)	y,
		real(double), intent(out)	z )

Compute the geocentric equatorial rectangular coordinates of the Sun, from Earth's heliocentric, spherical position.

Parameters

t1	Dynamical time in Julian Millennia after 2000.0
l0	Heliocentric longitude of Earth
b0	Heliocentric latitude of Earth
r0	Heliocentric distance of Earth
x	Geocentric rectangular X of planet (output)
y	Geocentric rectangular Y of planet (output)
z	Geocentric rectangular Z of planet (output)

Todo: To be disposed, has been replcaed by ecl_spher_2_eq_rect above

Definition at line 103 of file coordinates.f90.

References fk5(), and thesky_nutation::nutation().

Referenced by thesky_asteroids::asteroid_eq().

Here is the call graph for this function:

◆ ecl_2_eq()

subroutine thesky_coordinates::ecl_2_eq	(	real(double), intent(in)	l,
		real(double), intent(in)	b,
		real(double), intent(in)	eps,
		real(double), intent(out)	ra,
		real(double), intent(out)	dec )

Convert (geocentric) spherical ecliptical coordinates l,b (and eps) to spherical equatorial coordinates RA, Dec.

Parameters

l	Longitude (rad)
b	Latitude (rad)
eps	Obliquity of the ecliptic
ra	Right ascension (rad) (output)
dec	Declination (rad) (output)

See also: Expl. Supl. t.t. Astronimical Almanac 3rd Ed, Eq.14.43

Definition at line 571 of file coordinates.f90.

Referenced by thesky_visibility::comet_invisible(), thesky_planets::jupiterphys(), thesky_moon::moonpos_la(), thesky_planets::planet_position(), and thesky_planets::saturnphys().

◆ ecl_spher_2_eq_rect()

subroutine thesky_coordinates::ecl_spher_2_eq_rect	(	real(double), intent(in)	l,
		real(double), intent(in)	b,
		real(double), intent(in)	r,
		real(double), intent(in)	eps,
		real(double), intent(out)	x,
		real(double), intent(out)	y,
		real(double), intent(out)	z )

Convert spherical, ecliptical coordinates to rectangular, equatorial coordinates of an object - both geocentric.

Parameters

l	Heliocentric longitude of planet
b	Heliocentric latitude of planet
r	Heliocentric distance of planet
eps	Obliquity of the ecliptic
x	Geocentric rectangular X of planet (output)
y	Geocentric rectangular Y of planet (output)
z	Geocentric rectangular Z of planet (output)

Definition at line 73 of file coordinates.f90.

Referenced by thesky_comets::cometgc().

◆ eq2gal()

subroutine thesky_coordinates::eq2gal	(	real(double), intent(in)	ra,
		real(double), intent(in)	dec,
		real(double), intent(out)	l,
		real(double), intent(out)	b )

Convert spherical equatorial coordinates (RA, dec) to spherical galactic coordinates (l,b), for J2000.0!!!

Parameters

ra	Right ascension
dec	Declination
l	Longitude (output)
b	Latitude (output)

See also: Meeus, Astronomical Algorithms, 1998, Ch.13

Definition at line 724 of file coordinates.f90.

◆ eq2horiz()

subroutine thesky_coordinates::eq2horiz	(	real(double), intent(in)	ra,
		real(double), intent(in)	dec,
		real(double), intent(in)	agst,
		real(double), intent(out)	hh,
		real(double), intent(out)	az,
		real(double), intent(out)	alt,
		real(double), intent(in), optional	lat,
		real(double), intent(in), optional	lon )

Convert spherical equatorial coordinates (RA, dec, agst) to spherical horizontal coordinates (hh, az, alt)

Parameters

ra	Right ascension
dec	Declination
agst	Greenwich sidereal time
hh	Local hour angle (output)
az	Azimuth (output)
alt	Altitude (output)
lat	Geographical latitude (rad), optional
lon	Geographical longitude (rad), optional

See also: Expl. Supl. t.t. Astronimical Almanac 3rd Ed, Eq.14.44, 14.45

Definition at line 629 of file coordinates.f90.

References thesky_local::lat0, and thesky_local::lon0.

Referenced by thesky_moon::moonpos_la(), thesky_planets::planet_position(), thesky_planets::planet_position_la(), and thesky_sun::sunpos_la().

◆ eq_2_ecl()

subroutine thesky_coordinates::eq_2_ecl	(	real(double), intent(in)	ra,
		real(double), intent(in)	dec,
		real(double), intent(in)	eps,
		real(double), intent(out)	l,
		real(double), intent(out)	b )

Convert (geocentric) spherical equatorial coordinates RA, Dec (and eps) to spherical ecliptical coordinates l,b.

Parameters

ra	Right ascension (rad)
dec	Declination (rad)
eps	Obliquity of the ecliptic
l	Longitude (rad) (output)
b	Latitude (rad) (output)

See also: Expl. Supl. t.t. Astronimical Almanac 3rd Ed, Eq.14.42

Definition at line 598 of file coordinates.f90.

Referenced by thesky_stars::calcstars(), thesky_comets::cometgc(), and thesky_planets::jupiterphys().

◆ fk5()

subroutine thesky_coordinates::fk5	(	real(double), intent(in)	t,
		real(double), intent(inout)	l,
		real(double), intent(inout)	b )

Convert coordinates to the FK5 system.

Parameters

t	Dynamical time in Julian Millennia since 2000.0
l	Longitude (rad, I/O) (output)
b	Latitude (rad, I/O) (output)

Definition at line 538 of file coordinates.f90.

Referenced by calcsunxyz(), thesky_comets::cometgc(), and thesky_planets::planet_position().

◆ gal2eq()

subroutine thesky_coordinates::gal2eq	(	real(double), intent(in)	l,
		real(double), intent(in)	b,
		real(double), intent(out)	ra,
		real(double), intent(out)	dec )

Convert spherical galactic coordinates (l,b) to spherical equatorial coordinates (RA, dec), for J2000.0!!!

Parameters

l	Longitude
b	Latitude
ra	Right ascension (output)
dec	Declination (output)

Definition at line 753 of file coordinates.f90.

◆ geoc2topoc_ecl()

subroutine thesky_coordinates::geoc2topoc_ecl	(	real(double), intent(in)	gcl,
		real(double), intent(in)	gcb,
		real(double), intent(in)	gcr,
		real(double), intent(in)	gcs,
		real(double), intent(in)	eps,
		real(double), intent(in)	lst,
		real(double), intent(out)	tcl,
		real(double), intent(out)	tcb,
		real(double), intent(out)	tcs,
		real(double), intent(in), optional	lat,
		real(double), intent(in), optional	hgt )

Convert spherical ecliptical coordinates from the geocentric to the topocentric system.

Parameters

gcl	Geocentric ecliptic longitude of the object (rad)
gcb	Geocentric ecliptic latitude of the object (rad)
gcr	Geocentric distance of the object
gcs	Geocentric semi-diameter of the object (rad)
eps	Obliquity of the ecliptic (rad)
lst	Local sidereal time (rad)
tcl	Topocentric ecliptic longitude of the object (rad) (output)
tcb	Topocentric ecliptic latitude of the object (rad) (output)
tcs	Topocentric semi-diameter of the object (rad) (output)
lat	Latitude of the observer (rad, optional)
hgt	Altitude/elevation of the observer above sea level (metres, optional)

Note: lat/lat0 and hgt/height can be provided through the module TheSky_local (rad, and m), or through the optional arguments. Note that using the latter will update the former!

See also: Meeus, Astronomical Algorithms, 1998, Ch. 11 and 40

Definition at line 797 of file coordinates.f90.

References thesky_local::height, and thesky_local::lat0.

Referenced by thesky_planets::planet_position(), and thesky_planets::planet_position_la().

◆ geoc2topoc_eq()

subroutine thesky_coordinates::geoc2topoc_eq	(	real(double), intent(in)	gcra,
		real(double), intent(in)	gcd,
		real(double), intent(in)	gcr,
		real(double), intent(in)	gch,
		real(double), intent(out)	tcra,
		real(double), intent(out)	tcd,
		real(double), intent(in), optional	lat,
		real(double), intent(in), optional	hgt )

Convert geocentric equatorial coordinates to topocentric.

Parameters

gcra	Geocentric right ascension
gcd	Geocentric declination
gcr	Geocentric distance
gch	Geocentric hour angle
tcra	Topocentric right ascension (output)
tcd	Topocentric declination (output)
lat	Latitude of the observer (rad, optional)
hgt	Altitude/elevation of the observer above sea level (metres, optional)

Note: lat/lat0 and hgt/height can be provided through the module TheSky_local (rad, and m), or through the optional arguments. Note that using the latter will update the former!

See also: Meeus, Astronomical Algorithms, 1998, Ch. 11 and 40

Definition at line 858 of file coordinates.f90.

References thesky_local::height, and thesky_local::lat0.

Referenced by thesky_planets::planet_position_la().

◆ hc_spher_2_gc_rect()

subroutine thesky_coordinates::hc_spher_2_gc_rect	(	real(double), intent(in)	l,
		real(double), intent(in)	b,
		real(double), intent(in)	r,
		real(double), intent(in)	l0,
		real(double), intent(in)	b0,
		real(double), intent(in)	r0,
		real(double), intent(out)	x,
		real(double), intent(out)	y,
		real(double), intent(out)	z )

Compute the geocentric rectangular coordinates of a planet, from its and the Earth's heliocentric spherical position.

Parameters

l	Heliocentric longitude of planet
b	Heliocentric latitude of planet
r	Heliocentric distance of planet
l0	Heliocentric longitude of Earth
b0	Heliocentric latitude of Earth
r0	Heliocentric distance of Earth
x	Geocentric rectangular X of planet (output)
y	Geocentric rectangular Y of planet (output)
z	Geocentric rectangular Z of planet (output)

Definition at line 46 of file coordinates.f90.

Referenced by thesky_planets::planet_position(), and thesky_planets::saturnphys().

◆ horiz2eq()

subroutine thesky_coordinates::horiz2eq	(	real(double), intent(in)	az,
		real(double), intent(in)	alt,
		real(double), intent(in)	agst,
		real(double), intent(out)	hh,
		real(double), intent(out)	ra,
		real(double), intent(out)	dec,
		real(double), intent(in), optional	lat,
		real(double), intent(in), optional	lon )

Convert spherical horizontal coordinates (az, alt, agst) to spherical equatorial coordinates (hh, RA, dec)

Parameters

az	Azimuth
alt	Altitude
agst	Greenwich sidereal time
hh	Local hour angle (output)
ra	Right ascension (output)
dec	Declination (output)
lat	Geographical latitude (rad), optional
lon	Geographical longitude (rad), optional

See also: Expl. Supl. t.t. Astronimical Almanac 3rd Ed, Eq.14.46, 14.47

Definition at line 680 of file coordinates.f90.

References thesky_local::lat0, and thesky_local::lon0.

Referenced by thesky_visibility::limmag_zenith_jd().

◆ precess_ecl()

subroutine thesky_coordinates::precess_ecl	(	real(double), intent(in)	jd1,
		real(double), intent(in)	jd2,
		real(double), intent(inout)	l,
		real(double), intent(inout)	b )

Compute the precession of the equinoxes in geocentric ecliptical coordinates.

Parameters

jd1	Original Julian day
jd2	Target Julian day
l	Ecliptic longitude (I/O, rad) (output)
b	Ecliptic latitude (I/O, rad) (output)

See also: Meeus, Astronomical Algorithms, 1998, Ch.21, p.136

Definition at line 295 of file coordinates.f90.

Referenced by thesky_moon::elp_mpp02_lbr(), thesky_moonroutines::moonphys(), and thesky_planets::planet_position().

◆ precess_eq()

subroutine thesky_coordinates::precess_eq	(	real(double), intent(in)	jd1,
		real(double), intent(in)	jd2,
		real(double), intent(inout)	a1,
		real(double), intent(inout)	d1 )

Compute the precession of the equinoxes in equatorial coordinates, from jd1 to jd2.

Parameters

jd1	Original Julian day
jd2	Target Julian day
a1	Right ascension (IO, rad) (output)
d1	Declination (IO, rad) (output)

See also: Meeus, Astronomical Algorithms, 1998, Ch.21, p.134

Definition at line 210 of file coordinates.f90.

Referenced by thesky_stars::calcstars(), thesky_functions::const_id(), and thesky_moonroutines::moonphys().

◆ precess_eq_yr()

subroutine thesky_coordinates::precess_eq_yr	(	real(double), intent(in)	yr1,
		real(double), intent(in)	yr2,
		real(double), intent(inout)	a1,
		real(double), intent(inout)	d1 )

Compute the precession of the equinoxes in equatorial coordinates, from yr1 to yr2.

Parameters

yr1	Original year
yr2	Target year
a1	Right ascension (IO, rad) (output)
d1	Declination (IO, rad) (output)

See also: Meeus, Astronomical Algorithms, 1998, Ch.21, p.134

Definition at line 253 of file coordinates.f90.

◆ precess_orb()

subroutine thesky_coordinates::precess_orb	(	real(double), intent(in)	jd1,
		real(double), intent(in)	jd2,
		real(double), intent(inout)	i,
		real(double), intent(inout)	o1,
		real(double), intent(inout)	o2 )

Compute the precession of the equinoxes in orbital elements.

Parameters

jd1	Original Julian day
jd2	Target Julian day
i	Inclination (output)
o1	Argument of perihelion (output)
o2	Longitude of ascending node (output)

See also: Meeus, Astronomical Algorithms, 1998, Ch.24

Definition at line 341 of file coordinates.f90.

Referenced by thesky_asteroids::asteroid_elements().

◆ precess_xyz()

subroutine thesky_coordinates::precess_xyz	(	real(double), intent(in)	jd1,
		real(double), intent(in)	jd2,
		real(double), intent(inout)	x,
		real(double), intent(inout)	y,
		real(double), intent(inout)	z )

Compute the precession of the equinoxes in rectangular coordinates, from jd1 to jd2.

Parameters

jd1	Original Julian day
jd2	Target Julian day
x	Geocentric rectangular X (output)
y	Geocentric rectangular Y (output)
z	Geocentric rectangular Z (output)

See also: Meeus, Astronomical Algorithms, 1998, Ch. 21

Definition at line 148 of file coordinates.f90.

Referenced by thesky_comets::cometgc().

◆ rect_2_spher()

subroutine thesky_coordinates::rect_2_spher	(	real(double), intent(in)	x,
		real(double), intent(in)	y,
		real(double), intent(in)	z,
		real(double), intent(out)	l,
		real(double), intent(out)	b,
		real(double), intent(out)	r )

Convert rectangular coordinates x,y,z to spherical coordinates l,b,r.

Parameters

x	Rectangular x coordinate (same unit as r)
y	Rectangular y coordinate (same unit as r)
z	Rectangular z coordinate (same unit as r)
l	Longitude (rad) (output)
b	Latitude (rad) (output)
r	Distance (same unit as x,y,z) (output)

Definition at line 388 of file coordinates.f90.

Referenced by thesky_planets::planet_position(), and thesky_planets::saturnphys().

◆ refi()

real(double) function thesky_coordinates::refi	(	real(double), intent(in)	r,
		real(double), intent(in)	n,
		real(double), intent(in)	dndr )

The refraction integrand for atmospheric_refraction_apparent()

Parameters

r	The current distance from the centre of the Earth in metres
n	The refractive index at R
dndr	The rate the refractive index is changing at R

Return values

refi	The integrand of the refraction function

Definition at line 1302 of file coordinates.f90.

References refi().

Referenced by atmospheric_refraction_apparent(), and refi().

Here is the call graph for this function:

◆ refract()

real(double) function thesky_coordinates::refract	(	real(double), intent(in)	alt,
		real(double), intent(in), optional	press,
		real(double), intent(in), optional	temp )

Compute the atmospheric refraction for a given true altitude. You should add the result to the uncorrected altitude in order to obtain the observed altitude. Return 0 if alt + refract < -0.3°.

Parameters

alt	True (computed) altitude (rad)
press	Air pressure (hPa; optional)
temp	Air temperature (degrees Celsius; optional)

Return values

refract Refraction in altitude (rad). You should add the result to the uncorrected altitude.

See also

T. Saemundsson, "Atmospheric refraction", Sky & Telescope vol.72, p.70 (1986), converted to radians;
Meeus (1998), Eq. 16.4 ff.

Definition at line 910 of file coordinates.f90.

References refract().

Referenced by thesky_planets::planet_position(), thesky_planets::planet_position_la(), refract(), refract_sp(), thesky_riset::riset(), thesky_riset::riset_ipol(), and thesky_sun::sunpos_la().

Here is the call graph for this function:

◆ refract_sp()

real function thesky_coordinates::refract_sp	(	real, intent(in)	alt,
		real, intent(in), optional	press,
		real, intent(in), optional	temp )

Compute the atmospheric refraction for a given true altitude, using single-precision values. This is a wrapper for refract().

Parameters

alt	True (computed) altitude (rad)
press	Air pressure (hPa; optional)
temp	Air temperature (degrees Celsius; optional)

Return values

refract Refraction in altitude (rad). You should add the result to the uncorrected altitude.

See also: refract() for details.

Definition at line 951 of file coordinates.f90.

References refract(), and refract_sp().

Referenced by refract_sp().

Here is the call graph for this function:

◆ stratosphere_model()

subroutine thesky_coordinates::stratosphere_model	(	real(double), intent(in)	rt,
		real(double), intent(in)	tt,
		real(double), intent(in)	nt,
		real(double), intent(in)	a,
		real(double), intent(in)	r,
		real(double), intent(out)	n,
		real(double), intent(out)	dndr )

Stratosphere model for atmospheric_refraction_apparent()

Parameters

rt	The height of the tropopause from the centre of the Earth in metres
tt	The temperature at the tropopause in Kelvin
nt	The refractive index at the tropopause
a	Constant of the atmospheric model = G*MD/R
r	The current distance from the centre of the Earth in metres
n	The refractive index at R (output)
dndr	The rate the refractive index is changing at R (output)

Definition at line 1356 of file coordinates.f90.

Referenced by atmospheric_refraction_apparent().

◆ troposphere_model()

subroutine thesky_coordinates::troposphere_model	(	real(double), intent(in)	r0,
		real(double), intent(in)	t0,
		real(double), dimension(10), intent(in)	a,
		real(double), intent(in)	r,
		real(double), intent(out)	t,
		real(double), intent(out)	n,
		real(double), intent(out)	dndr )

Troposphere model for atmospheric_refraction_apparent()

Parameters

r0	The height of the observer from the centre of the Earth
t0	The temperature at the observer in Kelvin
a	Constants defined at the observer
r	The current distance from the centre of the Earth in metres
t	The temperature at R in Kelvin (output)
n	The refractive index at R (output)
dndr	The rate the refractive index is changing at R (output)

Definition at line 1325 of file coordinates.f90.

Referenced by atmospheric_refraction_apparent().

Functions/Subroutines

Detailed Description

Function/Subroutine Documentation

◆ aberration_ecl()

◆ aberration_eq()

◆ aref()

◆ atmospheric_refraction()

◆ atmospheric_refraction_apparent()

◆ calcsunxyz()

◆ ecl_2_eq()

◆ ecl_spher_2_eq_rect()

◆ eq2gal()

◆ eq2horiz()

◆ eq_2_ecl()

◆ fk5()

◆ gal2eq()

◆ geoc2topoc_ecl()

◆ geoc2topoc_eq()

◆ hc_spher_2_gc_rect()

◆ horiz2eq()

◆ precess_ecl()

◆ precess_eq()

◆ precess_eq_yr()

◆ precess_orb()

◆ precess_xyz()

◆ rect_2_spher()

◆ refi()

◆ refract()

◆ refract_sp()

◆ stratosphere_model()

◆ troposphere_model()