contains general purpose utility functions. More...

Functions
QString	getApplicationName ()
	Return the full name of stellarium, i.e. "stellarium 0.9.0". More...

QString	getApplicationVersion ()
	Return the version of stellarium, i.e. "0.9.0". More...

QString	getOperatingSystemInfo ()
	Return the name and the version of operating system, i.e. "Mac OS X 10.7". More...

QString	getUserAgentString ()
	Return the user agent name, i.e. "Stellarium/0.15.0 (Linux)". More...

double	hmsToRad (const unsigned int h, const unsigned int m, const double s)
	Convert an angle in hms format to radian. More...

double	dmsToRad (const int d, const unsigned int m, const double s)
	Convert an angle in +-dms format to radian. More...

void	radToHms (double rad, unsigned int &h, unsigned int &m, double &s)
	Convert an angle in radian to hms format. More...

void	radToDms (double rad, bool &sign, unsigned int &d, unsigned int &m, double &s)
	Convert an angle in radian to +-dms format. More...

void	radToDecDeg (double rad, bool &sign, double &deg)
	Convert an angle in radian to decimal degree. More...

QString	radToDecDegStr (const double angle, const int precision=4, const bool useD=false, const bool useC=false)
	Convert an angle in radian to a decimal degree string. More...

QString	radToHmsStrAdapt (const double angle)
	Convert an angle in radian to a hms formatted string. More...

QString	radToHmsStr (const double angle, const bool decimal=false)
	Convert an angle in radian to a hms formatted string. More...

QString	radToDmsStrAdapt (const double angle, const bool useD=false)
	Convert an angle in radian to a dms formatted string. More...

QString	radToDmsStr (const double angle, const bool decimal=false, const bool useD=false)
	Convert an angle in radian to a dms formatted string. More...

void	decDegToDms (double angle, bool &sign, unsigned int &d, unsigned int &m, double &s)
	Convert an angle in decimal degree to +-dms format. More...

QString	decDegToDmsStr (const double angle)
	Convert an angle in decimal degrees to a dms formatted string. More...

double	dmsStrToRad (const QString &s)
	Convert a dms formatted string to an angle in radian. More...

Vec3f	strToVec3f (const QStringList &s)
	Obtains a Vec3f from a string. More...

Vec3f	strToVec3f (const QString &s)
	Reads a Vec3f from a string, separated by commas. Example: 1.0,2.0,3.0. More...

Vec4d	strToVec4d (const QStringList &s)
	Like StelUtils::strToVec3f, but with 4 components and with double precision. More...

Vec4d	strToVec4d (const QString &s)
	Like StelUtils::strToVec3f, but with 4 components and with double precision. More...

QString	vec3fToStr (const Vec3f &v)
	Converts a Vec3f to a string in the same format that can be read by strToVec3f. More...

QString	vec4dToStr (const Vec4d &v)
	Converts a Vec4d to a string in the same format that can be read by strToVec4d. More...

QString	vec3fToHtmlColor (const Vec3f &v)
	Converts a Vec3f to HTML color notation. More...

Vec3f	htmlColorToVec3f (const QString &c)
	Converts a color in HTML notation to a Vec3f. More...

void	spheToRect (const double lng, const double lat, Vec3d &v)
	Convert from spherical coordinates to Rectangular direction. More...

void	spheToRect (const float lng, const float lat, Vec3f &v)
	Convert from spherical coordinates to Rectangular direction. More...

void	rectToSphe (double lng, double lat, const Vec3d &v)
	Convert from spherical coordinates to Rectangular direction. More...

void	rectToSphe (float lng, float lat, const Vec3d &v)
	Convert from spherical coordinates to Rectangular direction. More...

void	rectToSphe (float lng, float lat, const Vec3f &v)
	Convert from spherical coordinates to Rectangular direction. More...

void	equToEcl (const double raRad, const double decRad, const double eclRad, double lambdaRad, double betaRad)
	Coordinate Transformation from equatorial to ecliptical. More...

void	eclToEqu (const double lambdaRad, const double betaRad, const double eclRad, double raRad, double decRad)
	Coordinate Transformation from ecliptical to equatorial. More...

double	getDecAngle (const QString &str)
	Convert a string longitude, latitude, RA or Declination angle to radians. More...

bool	isPowerOfTwo (const int value)
	Check if a number is a power of 2. More...

int	getBiggerPowerOfTwo (int value)
	Return the first power of two bigger than the given value. More...

double	asinh (const double z)
	Return the inverse sinus hyperbolic of z. More...

int	imod (const int a, const int b)
	Integer modulo where the result is always positive. More...

void	getDateFromJulianDay (const double julianDay, int year, int month, int *day)
	Make from julianDay a year, month, day for the Julian Date julianDay represents. More...

void	getTimeFromJulianDay (const double julianDay, int hour, int minute, int second, int millis=NULL)
	Make from julianDay an hour, minute, second. More...

bool	getDateTimeFromISO8601String (const QString &iso8601Date, int y, int m, int d, int h, int min, float s)
	Parse an ISO8601 date string. More...

QString	julianDayToISO8601String (const double jd, bool addMS=false)
	Format the given Julian Day in (UTC) ISO8601 date string. More...

double	getJulianDayFromISO8601String (const QString &iso8601Date, bool *ok)
	Return the Julian Date matching the ISO8601 date string. More...

QString	localeDateString (const int year, const int month, const int day, const int dayOfWeek, const QString &fmt)
	Format the date and day-of-week per the format in fmt (see QDateTime::toString()). More...

QString	localeDateString (const int year, const int month, const int day, const int dayOfWeek)
	Format the date and day-of-week per the system locale's QLocale::ShortFormat. More...

double	getJDFromSystem ()
	Get the current Julian Date from system time. More...

double	qTimeToJDFraction (const QTime &time)
	Convert a time of day to the fraction of a Julian Day. More...

QTime	jdFractionToQTime (const double jd)
	Convert a fraction of a Julian Day to a QTime. More...

double	qDateTimeToJd (const QDateTime &dateTime)
	Convert a QT QDateTime class to julian day. More...

QDateTime	jdToQDateTime (const double &jd)
	Convert a julian day to a QDateTime. More...

bool	getJDFromDate (double *newjd, const int y, const int m, const int d, const int h, const int min, const int s)
	Compute Julian day number from calendar date. More...

int	numberOfDaysInMonthInYear (const int month, const int year)

bool	isLeapYear (const int year)

int	dayInYear (const int year, const int month, const int day)
	Find day number for date in year. More...

double	yearFraction (const int year, const int month, const double day)
	Return a fractional year like YYYY.ddddd. For negative years, the year number is decreased. E.g. -500.5 occurs in -501. More...

bool	changeDateTimeForRollover (int oy, int om, int od, int oh, int omin, int os, int ry, int rm, int rd, int rh, int rmin, int rs)

void	debugQVariantMap (const QVariant &m, const QString &indent="", const QString &key="")
	Output a QVariantMap to qDebug(). Formats like a tree where there are nested objects. More...

float	fastAcos (const float x)
	Compute acos(x) The taylor serie is not accurate around x=1 and x=-1. More...

float	fastExp (const float x)
	Compute exp(x) for small exponents x. More...

Vec3f	getNightColor (const Vec3f &dayColor)
	Get a night mode version of a color. More...

double	calculateSiderealPeriod (const double SemiMajorAxis)
	Calculate and return sidereal period in days from semi-major axis (in AU) More...

QString	hoursToHmsStr (const double hours)
	Convert decimal hours to hours, minutes, seconds. More...

long double	secondsSinceStart ()
	Get the number of seconds since program start. More...

double	getDeltaTwithoutCorrection (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByEspenakMeeus (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTBySchoch (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByClemence (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByIAU (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByAstronomicalEphemeris (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByTuckermanGoldstine (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByMullerStephenson (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByStephenson1978 (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByStephenson1997 (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTBySchmadelZech1979 (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByMorrisonStephenson1982 (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByStephensonMorrison1984 (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByStephensonMorrison1995 (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByStephensonHoulden (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByEspenak (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByBorkowski (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTBySchmadelZech1988 (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByChaprontTouze (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByJPLHorizons (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByMorrisonStephenson2004 (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByReijs (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByChaprontMeeus (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByMeeusSimons (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByMontenbruckPfleger (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByReingoldDershowitz (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByBanjevic (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByIslamSadiqQureshi (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByKhalidSultanaZaidi (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getDeltaTByStephensonMorrisonHohenkerk2016 (const double jDay)
	Get Delta-T estimation for a given date. More...

double	getMoonSecularAcceleration (const double jDay, const double ndot, const bool useDE43x)
	Get Secular Acceleration estimation for a given year. More...

double	getDeltaTStandardError (const double jDay)
	Get the standard error (sigma) for the value of DeltaT. More...

double	getMoonFluctuation (const double jDay)
	Get value of the Moon fluctuation Source: The Rotation of the Earth, and the Secular Accelerations of the Sun, Moon and Planets Spencer Jones, H. More...

template<typename T >
int	sign (T val)
	Sign function from http://stackoverflow.com/questions/1903954/is-there-a-standard-sign-function-signum-sgn-in-c-c. More...

float *	ComputeCosSinTheta (const int slices)
	Compute cosines and sines around a circle which is split in "segments" parts. More...

float *	ComputeCosSinRho (const int segments)
	Compute cosines and sines around a half-circle which is split in "segments" parts. More...

float *	ComputeCosSinRhoZone (const float dRho, const int segments, const float minAngle)
	Compute cosines and sines around part of a circle (from top to bottom) which is split in "segments" parts. More...

double	getDecYear (const int year, const int month, const int day)
	Compute date in decimal year format. More...

int	compareVersions (const QString v1, const QString v2)
	Comparison two string versions and return a result in range -1,0,1. More...

QByteArray	uncompress (const QByteArray &data)
	Uncompress gzip or zlib compressed data. More...

QByteArray	uncompress (QIODevice &device, qint64 maxBytes=-1)
	Uncompress (gzip/zlib) data from this QIODevice, which must be open and readable. More...

double	trunc (double x)

Detailed Description

contains general purpose utility functions.

Function Documentation

double StelUtils::asinh ( const double z )

Return the inverse sinus hyperbolic of z.

double StelUtils::calculateSiderealPeriod ( const double SemiMajorAxis )

Calculate and return sidereal period in days from semi-major axis (in AU)

int StelUtils::compareVersions	(	const QString	v1,
		const QString	v2
	)

Comparison two string versions and return a result in range -1,0,1.

Parameters

v1	string for version 1
v2	string for version 2

Returns: result (-1: v1<v2; 0: v1==v2; 1: v1>v2)

float* StelUtils::ComputeCosSinRho ( const int segments )

Compute cosines and sines around a half-circle which is split in "segments" parts.

Values are stored in the global static array cos_sin_rho. Used for the sin/cos values along a meridian for a spherical mesh.

Parameters

segments number of partitions (elsewhere called "stacks") for the half-circle

float* StelUtils::ComputeCosSinRhoZone	(	const float	dRho,
		const int	segments,
		const float	minAngle
	)

Compute cosines and sines around part of a circle (from top to bottom) which is split in "segments" parts.

Values are stored in the global static array cos_sin_rho. Used for the sin/cos values along a meridian. This allows leaving away pole caps. The array now contains values for the region minAngle+segments*phi

Parameters

dRho	a difference angle between the stops
segments	number of segments
minAngle	start angle inside the half-circle. maxAngle=minAngle+segments*phi

float* StelUtils::ComputeCosSinTheta ( const int slices )

Compute cosines and sines around a circle which is split in "segments" parts.

Values are stored in the global static array cos_sin_theta. Used for the sin/cos values along a latitude circle, equator, etc. for a spherical mesh.

Parameters

slices number of partitions (elsewhere called "segments") for the circle

int StelUtils::dayInYear	(	const int	year,
		const int	month,
		const int	day
	)

Find day number for date in year.

Meeus, Astronomical Algorithms 2nd ed., 1998, ch.7, p.65

void StelUtils::debugQVariantMap	(	const QVariant &	m,
		const QString &	indent = `""`,
		const QString &	key = `""`
	)

Output a QVariantMap to qDebug(). Formats like a tree where there are nested objects.

void StelUtils::decDegToDms	(	double	angle,
		bool &	sign,
		unsigned int &	d,
		unsigned int &	m,
		double &	s
	)

Convert an angle in decimal degree to +-dms format.

Parameters

angle	input angle in decimal degree
sign	true if positive, false otherwise
d	degree component
m	minute component
s	second component

QString StelUtils::decDegToDmsStr ( const double angle )

Convert an angle in decimal degrees to a dms formatted string.

Parameters

angle input angle in decimal degrees

double StelUtils::dmsStrToRad ( const QString & s )

Convert a dms formatted string to an angle in radian.

Parameters

s	The input string

double StelUtils::dmsToRad	(	const int	d,
		const unsigned int	m,
		const double	s
	)

Convert an angle in +-dms format to radian.

Parameters

d	degree component
m	arcmin component
s	arcsec component

Returns: angle in radian

void StelUtils::eclToEqu	(	const double	lambdaRad,
		const double	betaRad,
		const double	eclRad,
		double *	raRad,
		double *	decRad
	)

Coordinate Transformation from ecliptical to equatorial.

void StelUtils::equToEcl	(	const double	raRad,
		const double	decRad,
		const double	eclRad,
		double *	lambdaRad,
		double *	betaRad
	)

Coordinate Transformation from equatorial to ecliptical.

float StelUtils::fastAcos ( const float x )

inline

Compute acos(x) The taylor serie is not accurate around x=1 and x=-1.

Definition at line 315 of file StelUtils.hpp.

float StelUtils::fastExp ( const float x )

inline

Compute exp(x) for small exponents x.

Definition at line 321 of file StelUtils.hpp.

QString StelUtils::getApplicationName ( )

Return the full name of stellarium, i.e. "stellarium 0.9.0".

QString StelUtils::getApplicationVersion ( )

Return the version of stellarium, i.e. "0.9.0".

int StelUtils::getBiggerPowerOfTwo ( int value )

Return the first power of two bigger than the given value.

void StelUtils::getDateFromJulianDay	(	const double	julianDay,
		int *	year,
		int *	month,
		int *	day
	)

Make from julianDay a year, month, day for the Julian Date julianDay represents.

bool StelUtils::getDateTimeFromISO8601String	(	const QString &	iso8601Date,
		int *	y,
		int *	m,
		int *	d,
		int *	h,
		int *	min,
		float *	s
	)

Parse an ISO8601 date string.

Also handles negative and distant years.

double StelUtils::getDecAngle ( const QString & str )

Convert a string longitude, latitude, RA or Declination angle to radians.

Parameters

str	the angle in format something like these: +53d 51'21.6" - +53d51'21.6" -1d 10'31.8" - +46d6'31" 50D46'0"N - 123D47'59"W 123.567 N 123.567W -123.567 12h 14m 6s The degree separator may be a degree symbol (\xBA) in addition to a 'd' or 'D'.

Returns: the angle in radians. Latitude: North are positive, South are negative. Longitude: East is positive, West is negative. Note: if there is a N, S, E or W suffix, any leading + or - characters are ignored.

double StelUtils::getDecYear	(	const int	year,
		const int	month,
		const int	day
	)

Compute date in decimal year format.

Parameters

year
month
day

Returns: decimal year

double StelUtils::getDeltaTByAstronomicalEphemeris ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Astronomical Ephemeris (1960) for DeltaT computation. Sources: Spencer Jones, H., "The Rotation of the Earth, and the Secular Accelerations of the Sun, Moon and Planets", Monthly Notices of the Royal Astronomical Society, 99 (1939), 541-558 http://adsabs.harvard.edu/abs/1939MNRAS..99..541S or Explanatory Supplement to the Astr. Ephemeris, 1961, p.87. Also used by Mucke&Meeus, Canon of Solar Eclipses, Vienna 1983.

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByBanjevic ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Banjevic (2006) for DeltaT computation. Source: Ancient eclipses and dating the fall of Babylon Banjevic, B. Publications of the Astronomical Observatory of Belgrade, Vol. 80, p. 251-257 (2006) 2006POBeo..80..251B [http://adsabs.harvard.edu/abs/2006POBeo..80..251B]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByBorkowski ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Borkowski (1988) for DeltaT computation. Source: ELP 2000-85 and the dynamic time-universal time relation Borkowski, K. M. Astronomy and Astrophysics (ISSN 0004-6361), vol. 205, no. 1-2, Oct. 1988, p. L8-L10. 1988A&A...205L...8B [http://adsabs.harvard.edu/abs/1988A&A...205L...8B]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByChaprontMeeus ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Chapront, Chapront-Touze & Francou (1997) & Meeus (1998) for DeltaT computation

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByChaprontTouze ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Chapront-Touzé & Chapront (1991) for DeltaT computation

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds or 0 if year not in -391..1600

double StelUtils::getDeltaTByClemence ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Clemence (1948) for DeltaT computation, outdated but may be useful for science-historical purposes. Source: On the system of astronomical constants. Clemence, G. M. Astronomical Journal, Vol. 53, p. 169 1948AJ.....53..169C [http://adsabs.harvard.edu/abs/1948AJ.....53..169C]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByEspenak ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Espenak (1987, 1989) for DeltaT computation. This relation should not be used before around 1950 or after around 2100 (Espenak, pers. comm.).

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByEspenakMeeus ( const double jDay )

Get Delta-T estimation for a given date.

Note that this method is recommended for the year range: -1999 to +3000. It gives details for -500...+2150. Implementation of algorithm by Espenak & Meeus (2006) for DeltaT computation

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByIAU ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by IAU (1952) for DeltaT computation, outdated but may be useful for science-historical purposes. Source: Spencer Jones, H., "The Rotation of the Earth, and the Secular Accelerations of the Sun, Moon and Planets", Monthly Notices of the Royal Astronomical Society, 99 (1939), 541-558 http://adsabs.harvard.edu/abs/1939MNRAS..99..541S

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByIslamSadiqQureshi ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Islam, Sadiq & Qureshi (2008 + revisited 2013) for DeltaT computation. Source: Error Minimization of Polynomial Approximation of DeltaT Islam, S. & Sadiq, M. & Qureshi, M. S. Journal of Astrophysics & Astronomy, Vol. 29, p. 363–366 (2008) http://www.ias.ac.in/jaa/dec2008/JAA610.pdf Note: These polynomials are based on the uncorrected deltaT table from the Astronomical Almanac, thus ndot = -26.0 arcsec/cy^2. Meeus & Simons (2000) corrected the deltaT table for years before 1955.5 using ndot = -25.7376 arcsec/cy^2. Therefore the accuracies stated by Meeus & Simons are correct and cannot be compared with accuracies from Islam & Sadiq & Qureshi.

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByJPLHorizons ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of the "historical" part of the algorithm by JPL Horizons for DeltaT computation.

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds or 0 if year not in -2999..1620 (!)

double StelUtils::getDeltaTByKhalidSultanaZaidi ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of polinomial approximation of time period 1620-2013 for DeltaT by M. Khalid, Mariam Sultana and Faheem Zaidi (2014). Source: Delta T: Polynomial Approximation of Time Period 1620-2013 Journal of Astrophysics, Vol. 2014, Article ID 480964 https://doi.org/10.1155/2014/480964

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByMeeusSimons ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Meeus & Simons (2000) for DeltaT computation. Source: Polynomial approximations to Delta T, 1620-2000 AD Meeus, J.; Simons, L. Journal of the British Astronomical Association, vol.110, no.6, 323 2000JBAA..110..323M [http://adsabs.harvard.edu/abs/2000JBAA..110..323M]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds or 0 if year not in 1620..2000

double StelUtils::getDeltaTByMontenbruckPfleger ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Montenbruck & Pfleger (2000) for DeltaT computation, a data fit through the table of values found in Meeus, Astronomical algorithms (1991). Book "Astronomy on the Personal Computer" by O. Montenbruck & T. Pfleger (4th ed., 2000)

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds or 0 if not 1825<=year<2005

double StelUtils::getDeltaTByMorrisonStephenson1982 ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Morrison & Stephenson (1982) for DeltaT computation

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByMorrisonStephenson2004 ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Morrison & Stephenson (2004, 2005) for DeltaT computation. Sources: Historical values of the Earth's clock error ΔT and the calculation of eclipses Morrison, L. V.; Stephenson, F. R. Journal for the History of Astronomy (ISSN 0021-8286), Vol. 35, Part 3, No. 120, p. 327 - 336 (2004) 2004JHA....35..327M [http://adsabs.harvard.edu/abs/2004JHA....35..327M] Addendum: Historical values of the Earth's clock error Morrison, L. V.; Stephenson, F. R. Journal for the History of Astronomy (ISSN 0021-8286), Vol. 36, Part 3, No. 124, p. 339 (2005) 2005JHA....36..339M [http://adsabs.harvard.edu/abs/2005JHA....36..339M]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByMullerStephenson ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Muller & Stephenson (1975) for DeltaT computation. Source: The accelerations of the earth and moon from early astronomical observations Muller, P. M.; Stephenson, F. R. Growth rhythms and the history of the earth's rotation; Proceedings of the Interdisciplinary Winter Conference on Biological Clocks and Changes in the Earth's Rotation: Geophysical and Astronomical Consequences, Newcastle-upon-Tyne, England, January 8-10, 1974. (A76-18126 06-46) London, Wiley-Interscience, 1975, p. 459-533; Discussion, p. 534. 1975grhe.conf..459M [http://adsabs.harvard.edu/abs/1975grhe.conf..459M]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByReijs ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Reijs (2006) for DeltaT computation Details: http://www.iol.ie/~geniet/eng/DeltaTeval.htm

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByReingoldDershowitz ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Reingold & Dershowitz (1997, 2001, 2002, 2007) for DeltaT computation. This is again mostly a data fit based on the table in Meeus, Astronomical Algorithms (1991). This is the version given in the 3rd edition (2007) which added the fit for 1700..1799 omitted from previous editions.

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTBySchmadelZech1979 ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Schmadel & Zech (1979) for DeltaT computation. Outdated, but may be useful for science-historical purposes. Source: Polynomial approximations for the correction delta T E.T.-U.T. in the period 1800-1975 Schmadel, L. D.; Zech, G. Acta Astronomica, vol. 29, no. 1, 1979, p. 101-104. 1979AcA....29..101S [http://adsabs.harvard.edu/abs/1979AcA....29..101S]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

Note: The polynome is strictly applicable 1800...1975 only! Delivers values for the nearer edge (1800/1989) if jDay is outside.

double StelUtils::getDeltaTBySchmadelZech1988 ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Schmadel & Zech (1988) for DeltaT computation. Source: Empirical Transformations from U.T. to E.T. for the Period 1800-1988 Schmadel, L. D.; Zech, G. Astronomische Nachrichten 309, 219-221 1988AN....309..219S [http://adsabs.harvard.edu/abs/1988AN....309..219S]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

Note: The polynome is strictly applicable 1800...1988 only! Delivers values for the nearer edge (1800/1989) if jDay is outside.

double StelUtils::getDeltaTBySchoch ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Schoch (1931) for DeltaT computation, outdated but may be useful for science-historical purposes. Source: Schoch, C. (1931). Die sekulare Accelaration des Mondes und der Sonne. Astronomische Abhandlungen, Ergnzungshefte zu den Astronomischen Nachrichten, Band 8, B2. Kiel.

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByStephenson1978 ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Stephenson (1978) for DeltaT computation. Source: Pre-Telescopic Astronomical Observations Stephenson, F. R. Tidal Friction and the Earth's Rotation, Proceedings of a Workshop, held in Bielefeld, September 26-30, 1977, Edited by P. Brosche, and J. Sundermann. Berlin: Springer-Verlag, 1978, p.5 1978tfer.conf....5S [http://adsabs.harvard.edu/abs/1978tfer.conf....5S]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByStephenson1997 ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Stephenson (1997) for DeltaT computation. Source: Book "Historical Eclipses and Earth's Rotation" by F. R. Stephenson (1997) http://ebooks.cambridge.org/ebook.jsf?bid=CBO9780511525186

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByStephensonHoulden ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Stephenson & Houlden (1986) for DeltaT computation

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds or 0 if year > 1600

double StelUtils::getDeltaTByStephensonMorrison1984 ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Stephenson & Morrison (1984) for DeltaT computation Source: Long-term changes in the rotation of the earth - 700 B.C. to A.D. 1980. Stephenson, F. R.; Morrison, L. V. Philosophical Transactions, Series A (ISSN 0080-4614), vol. 313, no. 1524, Nov. 27, 1984, p. 47-70. 1984RSPTA.313...47S [http://adsabs.harvard.edu/abs/1984RSPTA.313...47S]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds or Zero if date outside years -391..1600

double StelUtils::getDeltaTByStephensonMorrison1995 ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Stephenson & Morrison (1995) for DeltaT computation Source: Long-Term Fluctuations in the Earth's Rotation: 700 BC to AD 1990. Stephenson, F. R.; Morrison, L. V. Philosophical Transactions: Physical Sciences and Engineering, Volume 351, Issue 1695, pp. 165-202 1995RSPTA.351..165S [http://adsabs.harvard.edu/abs/1995RSPTA.351..165S]

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTByStephensonMorrisonHohenkerk2016 ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of a spline approximation for time period -720-2016.0 for DeltaT by Stephenson, Morrison and Hohenkerk (2016). Source: Measurement of the Earth’s rotation: 720 BC to AD 2015 Proc. R. Soc. A 472: 20160404. https://doi.org/10.1098/rspa.2016.0404

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds. For times outside the limits, return result from the fitting parabola.

double StelUtils::getDeltaTByTuckermanGoldstine ( const double jDay )

Get Delta-T estimation for a given date.

Implementation of algorithm by Tuckerman (1962, 1964) & Goldstine (1973) for DeltaT computation

Parameters

jDay	the date and time expressed as a Julian day

Returns: Delta-T in seconds

double StelUtils::getDeltaTStandardError ( const double jDay )

Get the standard error (sigma) for the value of DeltaT.

Parameters

jDay the JD

Returns: sigma in seconds

double StelUtils::getDeltaTwithoutCorrection ( const double jDay )

Get Delta-T estimation for a given date.

This is just an "empty" correction functino, returning 0.

bool StelUtils::getJDFromDate	(	double *	newjd,
		const int	y,
		const int	m,
		const int	d,
		const int	h,
		const int	min,
		const int	s
	)

Compute Julian day number from calendar date.

Uses QDate functionality if possible, but also works for negative JD. Dates before 1582-10-15 are in the Julian Calendar.

Parameters

newjd	pointer to JD
y	Calendar year.
m	month, 1=January ... 12=December
d	day
h	hour
min	minute
s	second

Returns: true in all conceivable cases.

double StelUtils::getJDFromSystem ( )

Get the current Julian Date from system time.

Returns: the current Julian Date

double StelUtils::getJulianDayFromISO8601String	(	const QString &	iso8601Date,
		bool *	ok
	)

Return the Julian Date matching the ISO8601 date string.

Also handles negative and distant years.

double StelUtils::getMoonFluctuation ( const double jDay )

Get value of the Moon fluctuation Source: The Rotation of the Earth, and the Secular Accelerations of the Sun, Moon and Planets Spencer Jones, H.

Monthly Notices of the Royal Astronomical Society, 99 (1939), 541-558 1939MNRAS..99..541S [http://adsabs.harvard.edu/abs/1939MNRAS..99..541S]

Parameters

jDay the JD

Returns: fluctuation in seconds

double StelUtils::getMoonSecularAcceleration	(	const double	jDay,
		const double	ndot,
		const bool	useDE43x
	)

Get Secular Acceleration estimation for a given year.

Method described is here: http://eclipse.gsfc.nasa.gov/SEcat5/secular.html For adapting from -26 to -25.858, use -0.91072 * (-25.858 + 26.0) = -0.12932224 For adapting from -26 to -23.895, use -0.91072 * (-23.895 + 26.0) = -1.9170656

Parameters

jDay	the JD
ndot	value of n-dot (secular acceleration of the Moon) which should be used in the lunar ephemeris instead of the default values.
useDE43x	true if function should adapt calculation of the secular acceleration of the Moon to the DE43x ephemeris

Returns: SecularAcceleration in seconds

Note: n-dot for secular acceleration of the Moon in ELP2000-82B is -23.8946 "/cy/cy and for DE43x is -25.8 "/cy/cy

Vec3f StelUtils::getNightColor ( const Vec3f & dayColor )

inline

Get a night mode version of a color.

That is find the brightness of a color and set that in the red channel only

Definition at line 330 of file StelUtils.hpp.

QString StelUtils::getOperatingSystemInfo ( )

Return the name and the version of operating system, i.e. "Mac OS X 10.7".

void StelUtils::getTimeFromJulianDay	(	const double	julianDay,
		int *	hour,
		int *	minute,
		int *	second,
		int *	millis = `NULL`
	)

Make from julianDay an hour, minute, second.

QString StelUtils::getUserAgentString ( )

Return the user agent name, i.e. "Stellarium/0.15.0 (Linux)".

double StelUtils::hmsToRad	(	const unsigned int	h,
		const unsigned int	m,
		const double	s
	)

Convert an angle in hms format to radian.

Parameters

h	hour component
m	minute component
s	second component

Returns: angle in radian

QString StelUtils::hoursToHmsStr ( const double hours )

Convert decimal hours to hours, minutes, seconds.

Vec3f StelUtils::htmlColorToVec3f ( const QString & c )

Converts a color in HTML notation to a Vec3f.

Parameters

c	The HTML spec color string

int StelUtils::imod	(	const int	a,
		const int	b
	)

Integer modulo where the result is always positive.

bool StelUtils::isLeapYear ( const int year )

Returns: true if year is a leap year. Observes 1582 switch from Julian to Gregorian Calendar.

bool StelUtils::isPowerOfTwo ( const int value )

Check if a number is a power of 2.

QTime StelUtils::jdFractionToQTime ( const double jd )

Convert a fraction of a Julian Day to a QTime.

QDateTime StelUtils::jdToQDateTime ( const double & jd )

Convert a julian day to a QDateTime.

Parameters

jd	to convert

Returns: the matching UTC QDateTime

QString StelUtils::julianDayToISO8601String	(	const double	jd,
		bool	addMS = `false`
	)

Format the given Julian Day in (UTC) ISO8601 date string.

Also handles negative and distant years.

QString StelUtils::localeDateString	(	const int	year,
		const int	month,
		const int	day,
		const int	dayOfWeek,
		const QString &	fmt
	)

Format the date and day-of-week per the format in fmt (see QDateTime::toString()).

Uses the system locale, not the one set in Stellarium.

Returns: QString representing the formatted date

QString StelUtils::localeDateString	(	const int	year,
		const int	month,
		const int	day,
		const int	dayOfWeek
	)

Format the date and day-of-week per the system locale's QLocale::ShortFormat.

Returns: QString representing the formatted date

double StelUtils::qDateTimeToJd ( const QDateTime & dateTime )

Convert a QT QDateTime class to julian day.

Parameters

dateTime the UTC QDateTime to convert

Returns: the matching decimal Julian Day

double StelUtils::qTimeToJDFraction ( const QTime & time )

Convert a time of day to the fraction of a Julian Day.

Note that a Julian Day starts at 12:00, not 0:00, and so 12:00 == 0.0 and 0:00 == 0.5

void StelUtils::radToDecDeg	(	double	rad,
		bool &	sign,
		double &	deg
	)

Convert an angle in radian to decimal degree.

Parameters

rad	input angle in radian
sign	true if positive, false otherwise
deg	decimal degree

QString StelUtils::radToDecDegStr	(	const double	angle,
		const int	precision = `4`,
		const bool	useD = `false`,
		const bool	useC = `false`
	)

Convert an angle in radian to a decimal degree string.

Parameters

angle	input angle in radian
precision
useD	Define if letter "d" must be used instead of deg sign
useC	Define if function should use 0-360 degrees

void StelUtils::radToDms	(	double	rad,
		bool &	sign,
		unsigned int &	d,
		unsigned int &	m,
		double &	s
	)

Convert an angle in radian to +-dms format.

Parameters

rad	input angle in radian
sign	true if positive, false otherwise
d	degree component
m	minute component
s	second component

QString StelUtils::radToDmsStr	(	const double	angle,
		const bool	decimal = `false`,
		const bool	useD = `false`
	)

Convert an angle in radian to a dms formatted string.

Parameters

angle	input angle in radian
useD	Define if letter "d" must be used instead of deg sign
decimal	output decimal second value

QString StelUtils::radToDmsStrAdapt	(	const double	angle,
		const bool	useD = `false`
	)

Convert an angle in radian to a dms formatted string.

If the second, minute part is == 0, it is not output

Parameters

angle	input angle in radian
useD	Define if letter "d" must be used instead of deg sign

void StelUtils::radToHms	(	double	rad,
		unsigned int &	h,
		unsigned int &	m,
		double &	s
	)

Convert an angle in radian to hms format.

Parameters

rad	input angle in radian
h	hour component
m	minute component
s	second component

QString StelUtils::radToHmsStr	(	const double	angle,
		const bool	decimal = `false`
	)

Convert an angle in radian to a hms formatted string.

Parameters

angle	input angle in radian
decimal	output decimal second value

QString StelUtils::radToHmsStrAdapt ( const double angle )

Convert an angle in radian to a hms formatted string.

If the second, minute part is == 0, it is not output

Parameters

angle input angle in radian

void StelUtils::rectToSphe	(	double *	lng,
		double *	lat,
		const Vec3d &	v
	)

Convert from spherical coordinates to Rectangular direction.

Parameters

lng	double* to store longitude in radian
lat	double* to store latitude in radian
v	the input 3D vector

void StelUtils::rectToSphe	(	float *	lng,
		float *	lat,
		const Vec3d &	v
	)

Convert from spherical coordinates to Rectangular direction.

Parameters

lng	float* to store longitude in radian
lat	float* to store latitude in radian
v	the input 3D vector

void StelUtils::rectToSphe	(	float *	lng,
		float *	lat,
		const Vec3f &	v
	)

Convert from spherical coordinates to Rectangular direction.

Parameters

lng	float* to store longitude in radian
lat	float* to store latitude in radian
v	the input 3D vector

long double StelUtils::secondsSinceStart ( )

Get the number of seconds since program start.

Note: This is implemented in platform-specific ways to be as precise as possible, but there is a fallback for other platforms that might not be precise at all. This is currently used e.g. to measure FPS, but it should never be used for critical functionality.

template<typename T >

int StelUtils::sign ( T val )

Sign function from http://stackoverflow.com/questions/1903954/is-there-a-standard-sign-function-signum-sgn-in-c-c.

Definition at line 652 of file StelUtils.hpp.

void StelUtils::spheToRect	(	const double	lng,
		const double	lat,
		Vec3d &	v
	)

Convert from spherical coordinates to Rectangular direction.

Parameters

lng	longitude in radian
lat	latitude in radian
v	the resulting 3D unit vector

void StelUtils::spheToRect	(	const float	lng,
		const float	lat,
		Vec3f &	v
	)

Convert from spherical coordinates to Rectangular direction.

Parameters

lng	longitude in radian
lat	latitude in radian
v	the resulting 3D unit vector

Vec3f StelUtils::strToVec3f ( const QStringList & s )

Obtains a Vec3f from a string.

Parameters

s	the string describing the Vector with the form "x,y,z"

Returns: The corresponding vector

Deprecated:: Use the >> operator from Vec3f class

Vec3f StelUtils::strToVec3f ( const QString & s )

Reads a Vec3f from a string, separated by commas. Example: 1.0,2.0,3.0.

Vec4d StelUtils::strToVec4d ( const QStringList & s )

Like StelUtils::strToVec3f, but with 4 components and with double precision.

Vec4d StelUtils::strToVec4d ( const QString & s )

Like StelUtils::strToVec3f, but with 4 components and with double precision.

QByteArray StelUtils::uncompress ( const QByteArray & data )

Uncompress gzip or zlib compressed data.

QByteArray StelUtils::uncompress	(	QIODevice &	device,
		qint64	maxBytes = `-1`
	)

Uncompress (gzip/zlib) data from this QIODevice, which must be open and readable.

Parameters

device	The device to read from, must already be opened with an OpenMode supporting reading
maxBytes	The max. amount of bytes to read from the device, or -1 to read until EOF. Note that it always stops when inflate() returns Z_STREAM_END. Positive values can be used for interleaving compressed data with other data.

QString StelUtils::vec3fToHtmlColor ( const Vec3f & v )

Converts a Vec3f to HTML color notation.

Parameters

v	The vector

Returns: The string in HTML color notation "#rrggbb".

QString StelUtils::vec3fToStr ( const Vec3f & v )

Converts a Vec3f to a string in the same format that can be read by strToVec3f.

QString StelUtils::vec4dToStr ( const Vec4d & v )

Converts a Vec4d to a string in the same format that can be read by strToVec4d.

double StelUtils::yearFraction	(	const int	year,
		const int	month,
		const double	day
	)

Return a fractional year like YYYY.ddddd. For negative years, the year number is decreased. E.g. -500.5 occurs in -501.

Functions

Detailed Description

Function Documentation