SkyPoint Class Reference

#include <skypoint.h>

Inheritance diagram for SkyPoint:

Public Member Functions
	SkyPoint ()
	SkyPoint (const CachingDms &r, const CachingDms &d)
	SkyPoint (const dms &r, const dms &d)
	SkyPoint (double r, double d)
void	aberrate (const KSNumbers *num, bool reverse=false)
void	addEterms (void)
double	airmass () const
const dms &	alt () const
dms	altRefracted () const
dms	angularDistanceTo (const SkyPoint *sp, double *const positionAngle=nullptr) const
void	apparentCoord (long double jd0, long double jdf)
const dms &	az () const
void	B1950ToJ2000 (void)
bool	bendlight ()
SkyPoint	catalogueCoord (long double jdf)
bool	checkBendLight ()
bool	checkCircumpolar (const dms *gLat) const
const CachingDms &	dec () const
const CachingDms &	dec0 () const
SkyPoint	deprecess (const KSNumbers *num, long double epoch=J2000)
void	Equatorial1950ToGalactic (dms &galLong, dms &galLat)
void	EquatorialToHorizontal (const CachingDms *LST, const CachingDms *lat)
void	EquatorialToHorizontal (const dms *LST, const dms *lat)
SkyPoint	Eterms (void)
void	findEcliptic (const CachingDms *Obliquity, dms &EcLong, dms &EcLat)
void	GalacticToEquatorial1950 (const dms *galLong, const dms *galLat)
double	getLastPrecessJD () const
void	HorizontalToEquatorial (const dms *LST, const dms *lat)
void	J2000ToB1950 (void)
double	maxAlt (const dms &lat) const
double	minAlt (const dms &lat) const
SkyPoint	moveAway (const SkyPoint &from, double dist) const
void	nutate (const KSNumbers *num, const bool reverse=false)
bool	operator== (SkyPoint &p) const
dms	parallacticAngle (const CachingDms &LST, const CachingDms &lat)
void	precessFromAnyEpoch (long double jd0, long double jdf)
const CachingDms &	ra () const
const CachingDms &	ra0 () const
void	set (const dms &r, const dms &d)
void	setAlt (dms alt)
void	setAlt (double alt)
void	setAltRefracted (dms alt_apparent)
void	setAltRefracted (double alt_apparent)
void	setAz (dms az)
void	setAz (double az)
void	setDec (const CachingDms &d)
void	setDec (dms d)
void	setDec (double d)
void	setDec0 (const CachingDms &d)
void	setDec0 (dms d)
void	setDec0 (double d)
void	setFromEcliptic (const CachingDms *Obliquity, const dms &EcLong, const dms &EcLat)
void	setRA (const CachingDms &r)
void	setRA (dms &r)
void	setRA (double r)
void	setRA0 (CachingDms r)
void	setRA0 (dms r)
void	setRA0 (double r)
void	subtractEterms (void)
virtual void	updateCoords (const KSNumbers *num, bool includePlanets=true, const CachingDms *lat=nullptr, const CachingDms *LST=nullptr, bool forceRecompute=false)
virtual void	updateCoordsNow (const KSNumbers *num)
double	vGeocentric (double vhelio, long double jd)
double	vGeoToVHelio (double vgeo, long double jd)
double	vHeliocentric (double vlsr, long double jd)
double	vHelioToVlsr (double vhelio, long double jd)
double	vREarth (long double jd0)
double	vRSite (double vsite[3])
double	vRSun (long double jd)
double	vTopocentric (double vgeo, double vsite[3])
double	vTopoToVGeo (double vtopo, double vsite[3])

Static Public Member Functions
static dms	findAltitude (const SkyPoint *p, const KStarsDateTime &dt, const GeoLocation *geo, const double hour=0)
static dms	refract (const dms alt, bool conditional=true)
static double	refract (const double alt, bool conditional=true)
static double	refractionCorr (double alt)
static SkyPoint	timeTransformed (const SkyPoint *p, const KStarsDateTime &dt, const GeoLocation *geo, const double hour=0)
static dms	unrefract (const dms alt, bool conditional=true)
static double	unrefract (const double alt, bool conditional=true)

Static Public Attributes
static const double	altCrit = -1.0
static bool	implementationIsLibnova = false

Protected Member Functions
void	precess (const KSNumbers *num)

Protected Attributes
double	lastPrecessJD { 0 }

Detailed Description

The sky coordinates of a point in the sky.

The coordinates are stored in both Equatorial (Right Ascension, Declination) and Horizontal (Azimuth, Altitude) coordinate systems. Provides set/get functions for each coordinate angle, and functions to convert between the Equatorial and Horizon coordinate systems.

Because the coordinate values change slowly over time (due to precession, nutation), the "catalog coordinates" are stored (RA0, Dec0), which were the true coordinates on Jan 1, 2000. The true coordinates (RA, Dec) at any other epoch can be found from the catalog coordinates using updateCoords().

Stores dms coordinates for a point in the sky. for converting between coordinate systems.

Author

Jason Harris

Version

1.0

Definition at line 44 of file skypoint.h.

Constructor & Destructor Documentation

SkyPoint() [1/4]

SkyPoint::SkyPoint ( const dms & r, const dms & d )

inline

Default constructor: Sets RA, Dec and RA0, Dec0 according to arguments.

Does not set Altitude or Azimuth.

Parameters

r	Right Ascension
d	Declination

Definition at line 54 of file skypoint.h.

SkyPoint() [2/4]

SkyPoint::SkyPoint ( const CachingDms & r, const CachingDms & d )

inline

Definition at line 56 of file skypoint.h.

SkyPoint() [3/4]

SkyPoint::SkyPoint ( double r, double d )

inlineexplicit

Alternate constructor using double arguments, for convenience.

It behaves essentially like the default constructor.

Parameters

r	Right Ascension, expressed as a double
d	Declination, expressed as a double

Note

This also sets RA0 and Dec0

Definition at line 67 of file skypoint.h.

SkyPoint() [4/4]

SkyPoint::SkyPoint

(

)

Default constructor.

Sets nonsense values for RA, Dec etc

Definition at line 53 of file skypoint.cpp.

Member Function Documentation

aberrate()

void SkyPoint::aberrate	(	const KSNumbers *	num,
		bool	reverse = false )

Determine the effects of aberration for this SkyPoint.

Parameters

num	pointer to KSNumbers object containing current values of time-dependent variables.
reverse	bool, if true the aberration is removed.

Definition at line 454 of file skypoint.cpp.

addEterms()

void SkyPoint::addEterms

(

void

)

Coordinates in the FK4 catalog include the effect of aberration due to the ellipticity of the orbit of the Earth.

Coordinates in the FK5 catalog do not include these terms. In order to convert from B1950 (FK4) to actual mean places one has to use this function.

Definition at line 883 of file skypoint.cpp.

airmass()

double SkyPoint::airmass ( ) const

inline

Returns

the airmass of the point. Convenience method.

Note

Question: is it better to use alt or refracted alt? Minor difference, probably doesn't matter.

Definition at line 303 of file skypoint.h.

alt()

const dms & SkyPoint::alt ( ) const

inline

Returns

a pointer to the current Altitude.

Definition at line 281 of file skypoint.h.

altRefracted()

dms SkyPoint::altRefracted

(

)

const

Returns

refracted altitude. This function uses Options::useRefraction to determine whether refraction correction should be applied

Definition at line 1050 of file skypoint.cpp.

angularDistanceTo()

dms SkyPoint::angularDistanceTo	(	const SkyPoint *	sp,
		double *const	positionAngle = nullptr ) const

Computes the angular distance between two SkyObjects.

The algorithm to compute this distance is: cos(distance) = sin(d1)*sin(d2) + cos(d1)*cos(d2)*cos(a1-a2) where a1,d1 are the coordinates of the first object and a2,d2 are the coordinates of the second object. However this algorithm is not accurate when the angular separation is small. Meeus provides a different algorithm in page 111 which we implement here.

Parameters

sp	SkyPoint to which distance is to be calculated
positionAngle	if a non-null pointer is passed, the position angle [E of N] in degrees from this SkyPoint to sp is computed and stored in the passed variable.

Returns

dms angle representing angular separation.

Definition at line 899 of file skypoint.cpp.

apparentCoord()

void SkyPoint::apparentCoord	(	long double	jd0,
		long double	jdf )

Computes the apparent coordinates for this SkyPoint for any epoch, accounting for the effects of precession, nutation, and aberration.

Similar to updateCoords(), but the starting epoch need not be J2000, and the target epoch need not be the present time.

Parameters

jd0	Julian Day which identifies the original epoch
jdf	Julian Day which identifies the final epoch

Definition at line 700 of file skypoint.cpp.

az()

const dms & SkyPoint::az ( ) const

inline

Returns

a pointer to the current Azimuth.

Definition at line 275 of file skypoint.h.

B1950ToJ2000()

void SkyPoint::B1950ToJ2000

(

void

)

Exact precession from Besselian epoch 1950 to epoch J2000.

The coordinates referred to the first epoch are in the FK4 catalog, while the latter are in the Fk5 one.

Reference: Smith, C. A.; Kaplan, G. H.; Hughes, J. A.; Seidelmann, P. K.; Yallop, B. D.; Hohenkerk, C. Y. Astronomical Journal, vol. 97, Jan. 1989, p. 265-279

This transformation requires 4 steps:

• Correct E-terms
• Precess from B1950 to 1984, January 1st, 0h, using Newcomb expressions
• Add zero point correction in right ascension for 1984
• Precess from 1984, January 1st, 0h to J2000

Definition at line 773 of file skypoint.cpp.

bendlight()

bool SkyPoint::bendlight

(

)

Correct for the effect of "bending" of light around the sun for positions near the sun.

General Relativity tells us that a photon with an impact parameter b is deflected through an angle 1.75" (Rs / b) where Rs is the solar radius.

Returns

: true if the light was bent, false otherwise

Definition at line 425 of file skypoint.cpp.

catalogueCoord()

SkyPoint SkyPoint::catalogueCoord

(

long double

jdf

)

Computes the J2000.0 catalogue coordinates for this SkyPoint using the epoch removing aberration, nutation and precession Catalogue coordinates are in Ra0, Dec0 as well as Ra, Dec and lastPrecessJD is set to J2000.0.

Fixme

We do not undo nutation and aberration

catalogueCoord converts observed to J2000 using epoch jdf

Parameters

jdf	Julian Day which identifies the current epoch

Returns

SpyPoint containing J2000 coordinates

Definition at line 710 of file skypoint.cpp.

checkBendLight()

bool SkyPoint::checkBendLight

(

)

Check if this sky point is close enough to the sun for gravitational lensing to be significant.

Definition at line 399 of file skypoint.cpp.

checkCircumpolar()

bool SkyPoint::checkCircumpolar

(

const dms *

gLat

)

const

Check if this point is circumpolar at the given geographic latitude.

Definition at line 1045 of file skypoint.cpp.

dec()

const CachingDms & SkyPoint::dec ( ) const

inline

Returns

a pointer to the current Declination.

Definition at line 269 of file skypoint.h.

dec0()

const CachingDms & SkyPoint::dec0 ( ) const

inline

Returns

a pointer to the catalog Declination.

Definition at line 257 of file skypoint.h.

deprecess()

SkyPoint SkyPoint::deprecess	(	const KSNumbers *	num,
		long double	epoch = J2000 )

Obtain a Skypoint with RA0 and Dec0 set from the RA, Dec of this skypoint.

Also set the RA0, Dec0 of this SkyPoint if not set already and the target epoch is J2000.

Definition at line 257 of file skypoint.cpp.

Equatorial1950ToGalactic()

void SkyPoint::Equatorial1950ToGalactic	(	dms &	galLong,
		dms &	galLat )

Computes galactic coordinates from equatorial coordinates referred to epoch 1950.

RA and Dec are, therefore assumed to be B1950 coordinates.

Definition at line 735 of file skypoint.cpp.

EquatorialToHorizontal() [1/2]

void SkyPoint::EquatorialToHorizontal	(	const CachingDms *	LST,
		const CachingDms *	lat )

Determine the (Altitude, Azimuth) coordinates of the SkyPoint from its (RA, Dec) coordinates, given the local sidereal time and the observer's latitude.

Parameters

LST	pointer to the local sidereal time
lat	pointer to the geographic latitude

Definition at line 77 of file skypoint.cpp.

EquatorialToHorizontal() [2/2]

void SkyPoint::EquatorialToHorizontal	(	const dms *	LST,
		const dms *	lat )

Definition at line 70 of file skypoint.cpp.

Eterms()

SkyPoint SkyPoint::Eterms

(

void

)

Determine the E-terms of aberration In the past, the mean places of stars published in catalogs included the contribution to the aberration due to the ellipticity of the orbit of the Earth.

These terms, known as E-terms were almost constant, and in the newer catalogs (FK5) are not included. Therefore to convert from FK4 to FK5 one has to compute these E-terms.

Definition at line 868 of file skypoint.cpp.

findAltitude()

dms SkyPoint::findAltitude ( const SkyPoint * p, const KStarsDateTime & dt, const GeoLocation * geo, const double hour = 0 )

static

Compute the altitude of a given skypoint hour hours from the given date/time.

Parameters

p	SkyPoint whose altitude is to be computed (const pointer, the method works on a clone)
dt	Date/time that corresponds to 0 hour
geo	GeoLocation object specifying the location
hour	double specifying offset in hours from dt for which altitude is to be found

Returns

a dms containing (unrefracted?) altitude of the object at dt + hour hours at the given location

Note

This method is used in multiple places across KStars

Todo

Fix code duplication in AltVsTime and KSAlmanac by using this method instead! FIXME.

Definition at line 1111 of file skypoint.cpp.

findEcliptic()

void SkyPoint::findEcliptic	(	const CachingDms *	Obliquity,
		dms &	EcLong,
		dms &	EcLat )

Determine the Ecliptic coordinates of the SkyPoint, given the Julian Date.

The ecliptic coordinates are returned as reference arguments (since they are not stored internally)

Definition at line 187 of file skypoint.cpp.

GalacticToEquatorial1950()

void SkyPoint::GalacticToEquatorial1950	(	const dms *	galLong,
		const dms *	galLat )

Computes equatorial coordinates referred to 1950 from galactic ones referred to epoch B1950.

RA and Dec are, therefore assumed to be B1950 coordinates.

Definition at line 754 of file skypoint.cpp.

getLastPrecessJD()

double SkyPoint::getLastPrecessJD ( ) const

inline

Returns

the JD for the precessed coordinates

Definition at line 294 of file skypoint.h.

HorizontalToEquatorial()

void SkyPoint::HorizontalToEquatorial	(	const dms *	LST,
		const dms *	lat )

Determine the (RA, Dec) coordinates of the SkyPoint from its (Altitude, Azimuth) coordinates, given the local sidereal time and the observer's latitude.

Parameters

LST	pointer to the local sidereal time
lat	pointer to the geographic latitude

Definition at line 143 of file skypoint.cpp.

J2000ToB1950()

void SkyPoint::J2000ToB1950

(

void

)

Exact precession from epoch J2000 Besselian epoch 1950.

The coordinates referred to the first epoch are in the FK4 catalog, while the latter are in the Fk5 one.

Reference: Smith, C. A.; Kaplan, G. H.; Hughes, J. A.; Seidelmann, P. K.; Yallop, B. D.; Hohenkerk, C. Y. Astronomical Journal, vol. 97, Jan. 1989, p. 265-279

This transformation requires 4 steps:

• Precess from J2000 to 1984, January 1st, 0h
• Add zero point correction in right ascension for 1984
• Precess from 1984, January 1st, 0h, to B1950 using Newcomb expressions
• Correct E-terms

Definition at line 819 of file skypoint.cpp.

maxAlt()

double SkyPoint::maxAlt

(

const dms &

lat

)

const

Return the object's altitude at the upper culmination for the given latitude.

Returns

the maximum altitude in degrees

Definition at line 1136 of file skypoint.cpp.

minAlt()

double SkyPoint::minAlt

(

const dms &

lat

)

const

Return the object's altitude at the lower culmination for the given latitude.

Returns

the minimum altitude in degrees

Definition at line 1144 of file skypoint.cpp.

moveAway()

SkyPoint SkyPoint::moveAway	(	const SkyPoint &	from,
		double	dist ) const

Find the SkyPoint obtained by moving distance dist (arcseconds) away from the givenSkyPoint.

Parameters

dist	Distance to move through in arcseconds
from	The SkyPoint to move away from

Returns

a SkyPoint that is at the dist away from this SkyPoint in the direction away from

Definition at line 371 of file skypoint.cpp.

nutate()

void SkyPoint::nutate	(	const KSNumbers *	num,
		const bool	reverse = false )

Apply the effects of nutation to this SkyPoint.

Parameters

num	pointer to KSNumbers object containing current values of time-dependent variables.
reverse	bool, if true the nutation is removed

Definition at line 275 of file skypoint.cpp.

operator==()

bool SkyPoint::operator== ( SkyPoint & p ) const

inline

Returns

returns true if current epoch RA / Dec match

Definition at line 542 of file skypoint.h.

parallacticAngle()

dms SkyPoint::parallacticAngle	(	const CachingDms &	LST,
		const CachingDms &	lat )

Return the Parallactic Angle.

The parallactic angle is the angle between "up" and "north". See Jean Meeus' "Astronomical Algorithms" second edition, Chapter 14 for more details (especially Fig 4 on Pg 99). The angle returned in this case, between a vector of increasing altitude and a vector of increasing declination, is measured in the clockwise sense as seen on the sky.

Parameters

LST	Local Sidereal Time
lat	Latitude

Note

EquatorialToHorizontal() need not be called before invoking this, but it is wise to call updateCoords() to ensure ra() and dec() refer to the right epoch.

Returns

the parallactic angle in the clockwise sense

Definition at line 1152 of file skypoint.cpp.

precess()

void SkyPoint::precess ( const KSNumbers * num )

protected

Precess this SkyPoint's catalog coordinates to the epoch described by the given KSNumbers object.

Parameters

num	pointer to a KSNumbers object describing the target epoch.

Definition at line 223 of file skypoint.cpp.

precessFromAnyEpoch()

void SkyPoint::precessFromAnyEpoch	(	long double	jd0,
		long double	jdf )

General case of precession.

It precess from an original epoch to a final epoch. In this case RA0, and Dec0 from SkyPoint object represent the coordinates for the original epoch and not for J2000, as usual.

Parameters

jd0	Julian Day which identifies the original epoch
jdf	Julian Day which identifies the final epoch

Definition at line 625 of file skypoint.cpp.

ra()

const CachingDms & SkyPoint::ra ( ) const

inline

Returns

a pointer to the current Right Ascension.

Definition at line 263 of file skypoint.h.

ra0()

const CachingDms & SkyPoint::ra0 ( ) const

inline

Returns

a pointer to the catalog Right Ascension.

Definition at line 251 of file skypoint.h.

refract() [1/2]

static dms SkyPoint::refract ( const dms alt, bool conditional = true )

inlinestatic

Apply refraction correction to altitude.

Overloaded method using dms provided for convenience

See also

SkyPoint::refract( const double alt )

Definition at line 677 of file skypoint.h.

refract() [2/2]

double SkyPoint::refract ( const double alt, bool conditional = true )

static

Apply refraction correction to altitude, depending on conditional.

Parameters

alt	altitude to be corrected, in degrees
conditional	an optional boolean to decide whether to apply the correction or not

Note

If conditional is false, this method returns its argument unmodified. This is a convenience feature as it is often needed to gate these corrections.

Returns

altitude after refraction correction (if applicable), in degrees

Definition at line 1070 of file skypoint.cpp.

refractionCorr()

double SkyPoint::refractionCorr ( double alt )

static

Calculate refraction correction.

Parameter and return value are in degrees

Definition at line 1065 of file skypoint.cpp.

set()

void SkyPoint::set	(	const dms &	r,
		const dms &	d )

Sets RA, Dec and RA0, Dec0 according to arguments.

Does not set Altitude or Azimuth.

Parameters

r	Right Ascension
d	Declination

Note

This function also sets RA0 and Dec0 to the same values, so call at your own peril!

FIXME: This method must be removed, or an epoch argument must be added.

Definition at line 63 of file skypoint.cpp.

setAlt() [1/2]

void SkyPoint::setAlt ( dms alt )

inline

Sets Alt, the Altitude.

Parameters

alt

Altitude.

Definition at line 194 of file skypoint.h.

setAlt() [2/2]

void SkyPoint::setAlt ( double alt )

inline

Overloaded member function, provided for convenience.

It behaves essentially like the above function.

Parameters

alt	Altitude, expressed as a double.

Definition at line 220 of file skypoint.h.

setAltRefracted() [1/2]

void SkyPoint::setAltRefracted

(

dms

alt_apparent

)

Sets the apparent altitude, checking whether refraction corrections are enabled.

Parameters

alt_apparent

Apparent altitude (subject to Options::useRefraction())

Definition at line 1055 of file skypoint.cpp.

setAltRefracted() [2/2]

void SkyPoint::setAltRefracted

(

double

alt_apparent

)

Overloaded member function, provided for convenience.

It behaves essentially like the above function.

Parameters

alt_apparent

Apparent altitude (subject to Options::useRefraction())

Definition at line 1060 of file skypoint.cpp.

setAz() [1/2]

void SkyPoint::setAz ( dms az )

inline

Sets Az, the Azimuth.

Parameters

az

Azimuth.

Definition at line 230 of file skypoint.h.

setAz() [2/2]

void SkyPoint::setAz ( double az )

inline

Overloaded member function, provided for convenience.

It behaves essentially like the above function.

Parameters

az	Azimuth, expressed as a double.

Definition at line 241 of file skypoint.h.

setDec() [1/3]

void SkyPoint::setDec ( const CachingDms & d )

inline

Definition at line 173 of file skypoint.h.

setDec() [2/3]

void SkyPoint::setDec ( dms d )

inline

Sets Dec, the current Declination.

Parameters

d	Declination.

Definition at line 169 of file skypoint.h.

setDec() [3/3]

void SkyPoint::setDec ( double d )

inline

Overloaded member function, provided for convenience.

It behaves essentially like the above function.

Parameters

d	Declination, expressed as a double.

Definition at line 184 of file skypoint.h.

setDec0() [1/3]

void SkyPoint::setDec0 ( const CachingDms & d )

inline

Definition at line 123 of file skypoint.h.

setDec0() [2/3]

void SkyPoint::setDec0 ( dms d )

inline

Sets Dec0, the catalog Declination.

Parameters

d	catalog Declination.

Definition at line 119 of file skypoint.h.

setDec0() [3/3]

void SkyPoint::setDec0 ( double d )

inline

Overloaded member function, provided for convenience.

It behaves essentially like the above function.

Parameters

d	Declination, expressed as a double.

Definition at line 134 of file skypoint.h.

setFromEcliptic()

void SkyPoint::setFromEcliptic	(	const CachingDms *	Obliquity,
		const dms &	EcLong,
		const dms &	EcLat )

Set the current (RA, Dec) coordinates of the SkyPoint, given pointers to its Ecliptic (Long, Lat) coordinates, and to the current obliquity angle (the angle between the equator and ecliptic).

Definition at line 201 of file skypoint.cpp.

setRA() [1/3]

void SkyPoint::setRA ( const CachingDms & r )

inline

Definition at line 148 of file skypoint.h.

setRA() [2/3]

void SkyPoint::setRA ( dms & r )

inline

Sets RA, the current Right Ascension.

Parameters

r	Right Ascension.

Definition at line 144 of file skypoint.h.

setRA() [3/3]

void SkyPoint::setRA ( double r )

inline

Overloaded member function, provided for convenience.

It behaves essentially like the above function.

Parameters

r	Right Ascension, expressed as a double.

Definition at line 159 of file skypoint.h.

setRA0() [1/3]

void SkyPoint::setRA0 ( CachingDms r )

inline

Definition at line 98 of file skypoint.h.

setRA0() [2/3]

void SkyPoint::setRA0 ( dms r )

inline

Sets RA0, the catalog Right Ascension.

Parameters

r	catalog Right Ascension.

Definition at line 94 of file skypoint.h.

setRA0() [3/3]

void SkyPoint::setRA0 ( double r )

inline

Overloaded member function, provided for convenience.

It behaves essentially like the above function.

Parameters

r	Right Ascension, expressed as a double.

Definition at line 109 of file skypoint.h.

subtractEterms()

void SkyPoint::subtractEterms

(

void

)

Coordinates in the FK4 catalog include the effect of aberration due to the ellipticity of the orbit of the Earth.

Coordinates in the FK5 catalog do not include these terms. In order to convert from FK5 coordinates to B1950 (FK4) one has to use this function.

Definition at line 891 of file skypoint.cpp.

timeTransformed()

SkyPoint SkyPoint::timeTransformed ( const SkyPoint * p, const KStarsDateTime & dt, const GeoLocation * geo, const double hour = 0 )

static

returns a time-transformed SkyPoint.

See SkyPoint::findAltitude() for details

Todo

Fix this documentation.

Definition at line 1121 of file skypoint.cpp.

unrefract() [1/2]

static dms SkyPoint::unrefract ( const dms alt, bool conditional = true )

inlinestatic

Remove refraction correction.

Overloaded method using dms provided for convenience

See also

SkyPoint::unrefract( const double alt )

Definition at line 687 of file skypoint.h.

unrefract() [2/2]

double SkyPoint::unrefract ( const double alt, bool conditional = true )

static

Remove refraction correction, depending on conditional.

Parameters

alt	altitude from which refraction correction must be removed, in degrees
conditional	an optional boolean to decide whether to undo the correction or not

Returns

altitude without refraction correction, in degrees

Note

If conditional is false, this method returns its argument unmodified. This is a convenience feature as it is often needed to gate these corrections.

Definition at line 1091 of file skypoint.cpp.

updateCoords()

void SkyPoint::updateCoords ( const KSNumbers * num, bool includePlanets = true, const CachingDms * lat = nullptr, const CachingDms * LST = nullptr, bool forceRecompute = false )

virtual

Determine the current coordinates (RA, Dec) from the catalog coordinates (RA0, Dec0), accounting for both precession and nutation.

Parameters

num	pointer to KSNumbers object containing current values of time-dependent variables.
includePlanets	does nothing in this implementation (see KSPlanetBase::updateCoords()).
lat	does nothing in this implementation (see KSPlanetBase::updateCoords()).
LST	does nothing in this implementation (see KSPlanetBase::updateCoords()).
forceRecompute	reapplies precession, nutation and aberration even if the time passed since the last computation is not significant.

Reimplemented in KSEarthShadow, KSPlanetBase, and StarObject.

Definition at line 582 of file skypoint.cpp.

updateCoordsNow()

virtual void SkyPoint::updateCoordsNow ( const KSNumbers * num )

inlinevirtual

updateCoordsNow Shortcut for updateCoords( const KSNumbers *num, false, nullptr, nullptr, true)

Parameters

num	pointer to KSNumbers object containing current values of time-dependent variables.

Definition at line 382 of file skypoint.h.

vGeocentric()

double SkyPoint::vGeocentric	(	double	vhelio,
		long double	jd )

Computes the radial velocity of a source referred to the center of the earth from the radial velocity referred to the solar system barycenter.

Parameters

vhelio	radial velocity of the source referred to the barycenter of the solar system in km/s
jd	Epoch expressed as julian day to which the source coordinates refer to.

Returns

Radial velocity of the source referred to the center of the Earth in km/s

Definition at line 1015 of file skypoint.cpp.

vGeoToVHelio()

double SkyPoint::vGeoToVHelio	(	double	vgeo,
		long double	jd )

Computes the radial velocity of a source referred to the solar system barycenter from the velocity referred to the center of the earth.

Parameters

vgeo	radial velocity of the source referred to the center of the Earth [km/s]
jd	Epoch expressed as julian day to which the source coordinates refer to.

Returns

Radial velocity of the source referred to the solar system barycenter in km/s

Definition at line 1020 of file skypoint.cpp.

vHeliocentric()

double SkyPoint::vHeliocentric	(	double	vlsr,
		long double	jd )

Computes the radial velocity of a source referred to the solar system barycenter from the radial velocity referred to the Local Standard of Rest, aka known as VLSR.

To compute it we need the coordinates of the source the VLSR and the epoch for the source coordinates.

Parameters

vlsr	radial velocity of the source referred to the LSR in km/s
jd	Epoch expressed as julian day to which the source coordinates refer to.

Returns

Radial velocity of the source referred to the barycenter of the solar system in km/s

Definition at line 972 of file skypoint.cpp.

vHelioToVlsr()

double SkyPoint::vHelioToVlsr	(	double	vhelio,
		long double	jd )

Computes the radial velocity of a source referred to the Local Standard of Rest, also known as VLSR from the radial velocity referred to the solar system barycenter.

Parameters

vhelio	radial velocity of the source referred to the LSR in km/s
jd	Epoch expressed as julian day to which the source coordinates refer to.

Returns

Radial velocity of the source referred to the barycenter of the solar system in km/s

Definition at line 977 of file skypoint.cpp.

vREarth()

double SkyPoint::vREarth

(

long double

jd0

)

Computes the velocity of any object projected on the direction of the source.

Parameters

jd0	Julian day for which we compute the direction of the source

Returns

velocity of the Earth projected on the direction of the source kms-1

Definition at line 982 of file skypoint.cpp.

vRSite()

double SkyPoint::vRSite

(

double

vsite[3]

)

Computes the velocity of any object (observer's site) projected on the direction of the source.

Parameters

vsite

velocity of that object in cartesian coordinates

Returns

velocity of the object projected on the direction of the source kms-1

Definition at line 1025 of file skypoint.cpp.

vRSun()

double SkyPoint::vRSun

(

long double

jd

)

Computes the velocity of the Sun projected on the direction of the source.

Parameters

jd	Epoch expressed as julian day to which the source coordinates refer to.

Returns

Radial velocity of the source referred to the barycenter of the solar system in km/s

Definition at line 934 of file skypoint.cpp.

vTopocentric()

double SkyPoint::vTopocentric	(	double	vgeo,
		double	vsite[3] )

Computes the radial velocity of a source referred to the observer site on the surface of the earth from the geocentric velocity and the velocity of the site referred to the center of the Earth.

Parameters

vgeo	radial velocity of the source referred to the center of the earth in km/s
vsite	Velocity at which the observer moves referred to the center of the earth.

Returns

Radial velocity of the source referred to the observer's site in km/s

Definition at line 1040 of file skypoint.cpp.

vTopoToVGeo()

double SkyPoint::vTopoToVGeo	(	double	vtopo,
		double	vsite[3] )

Computes the radial velocity of a source referred to the center of the Earth from the radial velocity referred to an observer site on the surface of the earth.

Parameters

vtopo	radial velocity of the source referred to the observer's site in km/s
vsite	Velocity at which the observer moves referred to the center of the earth.

Returns

Radial velocity of the source referred the center of the earth in km/s

Definition at line 1035 of file skypoint.cpp.

Member Data Documentation

altCrit

const double SkyPoint::altCrit = -1.0

static

Critical height for atmospheric refraction corrections.

Below this, the height formula produces meaningless results and the correction value is just interpolated.

Definition at line 718 of file skypoint.h.

implementationIsLibnova

bool SkyPoint::implementationIsLibnova = false

static

Definition at line 759 of file skypoint.h.

lastPrecessJD

double SkyPoint::lastPrecessJD { 0 }

protected

Definition at line 786 of file skypoint.h.

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The documentation for this class was generated from the following files:

• skypoint.h
• skypoint.cpp