SkyPoint

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#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 dmsalt () const
 
dms altRefracted () const
 
dms angularDistanceTo (const SkyPoint *sp, double *const positionAngle=nullptr) const
 
void apparentCoord (long double jd0, long double jdf)
 
const dmsaz () const
 
void B1950ToJ2000 (void)
 
bool bendlight ()
 
SkyPoint catalogueCoord (long double jdf)
 
bool checkBendLight ()
 
bool checkCircumpolar (const dms *gLat) const
 
const CachingDmsdec () const
 
const CachingDmsdec0 () 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)
 
long double getLastPrecessJD () const
 
void HorizontalToEquatorial (const dms *LST, const dms *lat)
 
bool isValid () const
 
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 CachingDmsra () const
 
const CachingDmsra0 () 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

long 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
rRight Ascension
dDeclination

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
rRight Ascension, expressed as a double
dDeclination, 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
numpointer to KSNumbers object containing current values of time-dependent variables.
reversebool, 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
spSkyPoint to which distance is to be calculated
positionAngleif 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
jd0Julian Day which identifies the original epoch
jdfJulian 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
jdfJulian 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
LSTpointer to the local sidereal time
latpointer 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
pSkyPoint whose altitude is to be computed (const pointer, the method works on a clone)
dtDate/time that corresponds to 0 hour
geoGeoLocation object specifying the location
hourdouble 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()

long 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
LSTpointer to the local sidereal time
latpointer to the geographic latitude

Definition at line 143 of file skypoint.cpp.

◆ isValid()

bool SkyPoint::isValid ( ) const
inline

isValid Check if the RA and DE fall within expected range

Returns
True if valid, false otherwise.

Definition at line 312 of file skypoint.h.

◆ 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
distDistance to move through in arcseconds
fromThe 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
numpointer to KSNumbers object containing current values of time-dependent variables.
reversebool, 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 551 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
LSTLocal Sidereal Time
latLatitude
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
numpointer 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
jd0Julian Day which identifies the original epoch
jdfJulian 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 686 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
altaltitude to be corrected, in degrees
conditionalan 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
rRight Ascension
dDeclination
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
altAltitude.

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
altAltitude, 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_apparentApparent 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_apparentApparent 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
azAzimuth.

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
azAzimuth, 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
dDeclination.

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
dDeclination, 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
dcatalog 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
dDeclination, 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
rRight 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
rRight 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
rcatalog 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
rRight 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 696 of file skypoint.h.

◆ unrefract() [2/2]

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

Remove refraction correction, depending on conditional.

Parameters
altaltitude from which refraction correction must be removed, in degrees
conditionalan 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
numpointer to KSNumbers object containing current values of time-dependent variables.
includePlanetsdoes nothing in this implementation (see KSPlanetBase::updateCoords()).
latdoes nothing in this implementation (see KSPlanetBase::updateCoords()).
LSTdoes nothing in this implementation (see KSPlanetBase::updateCoords()).
forceRecomputereapplies 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
numpointer to KSNumbers object containing current values of time-dependent variables.

Definition at line 391 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
vhelioradial velocity of the source referred to the barycenter of the solar system in km/s
jdEpoch 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
vgeoradial velocity of the source referred to the center of the Earth [km/s]
jdEpoch 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
vlsrradial velocity of the source referred to the LSR in km/s
jdEpoch 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
vhelioradial velocity of the source referred to the LSR in km/s
jdEpoch 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
jd0Julian 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
vsitevelocity 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
jdEpoch 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
vgeoradial velocity of the source referred to the center of the earth in km/s
vsiteVelocity 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
vtoporadial velocity of the source referred to the observer's site in km/s
vsiteVelocity 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 727 of file skypoint.h.

◆ implementationIsLibnova

bool SkyPoint::implementationIsLibnova = false
static

Definition at line 768 of file skypoint.h.

◆ lastPrecessJD

long double SkyPoint::lastPrecessJD { 0 }
protected

Definition at line 795 of file skypoint.h.


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