KStarsDateTime Class Reference

#include <kstarsdatetime.h>

Inheritance diagram for KStarsDateTime:

Public Types
enum	EpochType { JULIAN , BESSELIAN }
Public Types inherited from QDateTime
enum	YearRange

Public Member Functions
	KStarsDateTime ()
	KStarsDateTime (const QDate &_d, const QTime &_t, Qt::TimeSpec timeSpec=Qt::UTC)
	KStarsDateTime (const QDateTime &qdt)
	KStarsDateTime (long double djd)
KStarsDateTime	addDays (int nd) const
KStarsDateTime	addSecs (double s) const
long double	djd () const
double	epoch () const
dms	gst () const
QTime	GSTtoUT (dms GST) const
bool	operator!= (const KStarsDateTime &d) const
bool	operator< (const KStarsDateTime &d) const
bool	operator<= (const KStarsDateTime &d) const
bool	operator== (const KStarsDateTime &d) const
bool	operator> (const KStarsDateTime &d) const
bool	operator>= (const KStarsDateTime &d) const
void	setDate (const QDate &d)
void	setDJD (long double jd)
bool	setFromEpoch (const QString &e)
void	setFromEpoch (double e)
bool	setFromEpoch (double e, EpochType type)
void	setTime (const QTime &t)
	KStarsDateTime (const KStarsDateTime &kdt)
KStarsDateTime &	operator= (const KStarsDateTime &kdt) noexcept
Public Member Functions inherited from QDateTime
	QDateTime (const QDateTime &other)
	QDateTime (QDate date, QTime time)
	QDateTime (QDate date, QTime time, const QTimeZone &timeZone)
	QDateTime (QDate date, QTime time, Qt::TimeSpec spec, int offsetSeconds)
	QDateTime (QDateTime &&other)
QDateTime	addDays (qint64 ndays) const const
QDateTime	addDuration (std::chrono::milliseconds msecs) const const
QDateTime	addMonths (int nmonths) const const
QDateTime	addMSecs (qint64 msecs) const const
QDateTime	addSecs (qint64 s) const const
QDateTime	addYears (int nyears) const const
QDate	date () const const
qint64	daysTo (const QDateTime &other) const const
bool	isDaylightTime () const const
bool	isNull () const const
bool	isValid () const const
qint64	msecsTo (const QDateTime &other) const const
int	offsetFromUtc () const const
bool	operator!= (const QDateTime &lhs, const QDateTime &rhs)
QDateTime	operator+ (const QDateTime &dateTime, std::chrono::milliseconds duration)
QDateTime	operator+ (std::chrono::milliseconds duration, const QDateTime &dateTime)
QDateTime &	operator+= (std::chrono::milliseconds duration)
QDateTime	operator- (const QDateTime &dateTime, std::chrono::milliseconds duration)
std::chrono::milliseconds	operator- (const QDateTime &lhs, const QDateTime &rhs)
QDateTime &	operator-= (std::chrono::milliseconds duration)
bool	operator< (const QDateTime &lhs, const QDateTime &rhs)
QDataStream &	operator<< (QDataStream &out, const QDateTime &dateTime)
bool	operator<= (const QDateTime &lhs, const QDateTime &rhs)
QDateTime &	operator= (const QDateTime &other)
bool	operator== (const QDateTime &lhs, const QDateTime &rhs)
bool	operator> (const QDateTime &lhs, const QDateTime &rhs)
bool	operator>= (const QDateTime &lhs, const QDateTime &rhs)
QDataStream &	operator>> (QDataStream &in, QDateTime &dateTime)
qint64	secsTo (const QDateTime &other) const const
void	setDate (QDate date)
void	setMSecsSinceEpoch (qint64 msecs)
void	setOffsetFromUtc (int offsetSeconds)
void	setSecsSinceEpoch (qint64 secs)
void	setTime (QTime time)
void	setTimeSpec (Qt::TimeSpec spec)
void	setTimeZone (const QTimeZone &toZone)
void	swap (QDateTime &other)
QTime	time () const const
QTimeZone	timeRepresentation () const const
Qt::TimeSpec	timeSpec () const const
QTimeZone	timeZone () const const
QString	timeZoneAbbreviation () const const
CFDateRef	toCFDate () const const
QDateTime	toLocalTime () const const
qint64	toMSecsSinceEpoch () const const
NSDate *	toNSDate () const const
QDateTime	toOffsetFromUtc (int offsetSeconds) const const
qint64	toSecsSinceEpoch () const const
std::chrono::sys_time< std::chrono::milliseconds >	toStdSysMilliseconds () const const
std::chrono::sys_seconds	toStdSysSeconds () const const
QString	toString (const QString &format, QCalendar cal) const const
QString	toString (QStringView format, QCalendar cal) const const
QString	toString (Qt::DateFormat format) const const
QDateTime	toTimeSpec (Qt::TimeSpec spec) const const
QDateTime	toTimeZone (const QTimeZone &timeZone) const const
QDateTime	toUTC () const const

Static Public Member Functions
static KStarsDateTime	currentDateTime ()
static KStarsDateTime	currentDateTimeUtc ()
static long double	epochToJd (double epoch, EpochType type=JULIAN)
static KStarsDateTime	fromString (const QString &s)
static double	jdToEpoch (long double jd, EpochType type=JULIAN)
static double	stringToEpoch (const QString &eName, bool &ok)
Static Public Member Functions inherited from QDateTime
QDateTime	currentDateTime ()
QDateTime	currentDateTime (const QTimeZone &zone)
QDateTime	currentDateTimeUtc ()
qint64	currentMSecsSinceEpoch ()
qint64	currentSecsSinceEpoch ()
QDateTime	fromCFDate (CFDateRef date)
QDateTime	fromMSecsSinceEpoch (qint64 msecs)
QDateTime	fromMSecsSinceEpoch (qint64 msecs, const QTimeZone &timeZone)
QDateTime	fromMSecsSinceEpoch (qint64 msecs, Qt::TimeSpec spec, int offsetSeconds)
QDateTime	fromNSDate (const NSDate *date)
QDateTime	fromSecsSinceEpoch (qint64 secs)
QDateTime	fromSecsSinceEpoch (qint64 secs, const QTimeZone &timeZone)
QDateTime	fromSecsSinceEpoch (qint64 secs, Qt::TimeSpec spec, int offsetSeconds)
QDateTime	fromStdLocalTime (const std::chrono::local_time< std::chrono::milliseconds > &time)
QDateTime	fromStdTimePoint (const std::chrono::local_time< std::chrono::milliseconds > &time)
QDateTime	fromStdTimePoint (const std::chrono::time_point< Clock, Duration > &time)
QDateTime	fromStdZonedTime (const std::chrono::zoned_time< std::chrono::milliseconds, const std::chrono::time_zone * > &time)
QDateTime	fromString (const QString &string, const QString &format, QCalendar cal)
QDateTime	fromString (const QString &string, QStringView format, QCalendar cal)
QDateTime	fromString (const QString &string, Qt::DateFormat format)
QDateTime	fromString (QStringView string, QStringView format, QCalendar cal)
QDateTime	fromString (QStringView string, Qt::DateFormat format)

Static Public Attributes
static constexpr const double	B1900 = 2415020.31352
static constexpr const double	JD_PER_BYEAR = 365.242198781

Additional Inherited Members
Public Attributes inherited from QDateTime
	First
	Last

Detailed Description

Extension of QDateTime for KStars KStarsDateTime can represent the date/time as a Julian Day, using a long double, in which the fractional portion encodes the time of day to a precision of a less than a second.

Also adds Greenwich Sidereal Time and "epoch", which is just the date expressed as a floating point number representing the year, with the fractional part representing the date and time (with poor time resolution; typically the Epoch is only taken to the hundredths place, which is a few days).

Note

Local time and Local sideral time are not handled here. Because they depend on the geographic location, they are part of the GeoLocation class.

The default timespec is UTC unless the passed value has different timespec value.

See also

GeoLocation::GSTtoLST()

GeoLocation::UTtoLT()

Author

Jason Harris

Jasem Mutlaq

Version

1.1

Definition at line 35 of file kstarsdatetime.h.

Member Enumeration Documentation

EpochType

enum KStarsDateTime::EpochType

description options

Note

After 1976, the IAU standard for epochs is Julian Years.

Enumerator
JULIAN	Julian epoch (see http://scienceworld.wolfram.com/astronomy/JulianEpoch.html)
BESSELIAN	Besselian epoch (see http://scienceworld.wolfram.com/astronomy/BesselianEpoch.html)

Definition at line 185 of file kstarsdatetime.h.

Constructor & Destructor Documentation

KStarsDateTime() [1/5]

KStarsDateTime::KStarsDateTime

(

)

Default constructor Creates a date/time at J2000 (noon on Jan 1, 200)

Note

This sets the timespec to UTC.

Definition at line 16 of file kstarsdatetime.cpp.

KStarsDateTime() [2/5]

KStarsDateTime::KStarsDateTime ( long double djd )

explicit

Constructor Creates a date/time at the specified Julian Day.

jd The Julian Day

Note

This sets the timespec to UTC.

Definition at line 66 of file kstarsdatetime.cpp.

KStarsDateTime() [3/5]

KStarsDateTime::KStarsDateTime

(

const KStarsDateTime &

kdt

)

Copy constructor kdt The KStarsDateTime object to copy.

Note

The timespec is copied from kdt.

Definition at line 22 of file kstarsdatetime.cpp.

KStarsDateTime() [4/5]

KStarsDateTime::KStarsDateTime ( const QDateTime & qdt )

explicit

Copy constructor qdt The QDateTime object to copy.

Note

The timespec is copied from qdt.

Definition at line 46 of file kstarsdatetime.cpp.

KStarsDateTime() [5/5]

KStarsDateTime::KStarsDateTime	(	const QDate &	_d,
		const QTime &	_t,
		Qt::TimeSpec	timeSpec = Qt::UTC )

Constructor Create a KStarsDateTimne based on the specified Date and Time.

_d The QDate to assign _t The QTime to assign timespec The desired timespec, UTC by default.

Definition at line 57 of file kstarsdatetime.cpp.

Member Function Documentation

addDays()

KStarsDateTime KStarsDateTime::addDays ( int nd ) const

inline

Modify the Date/Time by adding a number of days.

nd the number of days to add. The number can be negative.

Definition at line 110 of file kstarsdatetime.h.

addSecs()

KStarsDateTime KStarsDateTime::addSecs

(

double

s

)

const

Returns

a KStarsDateTime that is the given number of seconds later than this KStarsDateTime. s the number of seconds to add. The number can be negative.

Definition at line 153 of file kstarsdatetime.cpp.

currentDateTime()

KStarsDateTime KStarsDateTime::currentDateTime ( )

static

Returns

the date and time according to the CPU clock

Definition at line 73 of file kstarsdatetime.cpp.

currentDateTimeUtc()

KStarsDateTime KStarsDateTime::currentDateTimeUtc ( )

static

Returns

the UTC date and time according to the CPU clock

Definition at line 82 of file kstarsdatetime.cpp.

djd()

long double KStarsDateTime::djd ( ) const

inline

Returns

the julian day as a long double, including the time as the fractional portion.

Definition at line 163 of file kstarsdatetime.h.

epoch()

double KStarsDateTime::epoch ( ) const

inline

This is (approximately) the year expressed as a floating-point value.

Returns

the (Julian) epoch value of the Date/Time.

See also

setFromEpoch()

Note

The definition of Julian Epoch used here comes from http://scienceworld.wolfram.com/astronomy/JulianEpoch.html

Definition at line 197 of file kstarsdatetime.h.

epochToJd()

long double KStarsDateTime::epochToJd ( double epoch, EpochType type = JULIAN )

static

Takes in an epoch and returns a Julian Date.

Returns

the Julian Date (date with fraction)

Parameters

epoch	A floating-point year value specifying the Epoch
type	JULIAN or BESSELIAN depending on what convention the epoch is specified in

Definition at line 256 of file kstarsdatetime.cpp.

fromString()

KStarsDateTime KStarsDateTime::fromString ( const QString & s )

static

Returns

a KStarsDateTime object parsed from the given string.

Note

This function is format-agnostic; it will try several formats when parsing the string.

Parameters

s	the string expressing the date/time to be parsed.

Definition at line 91 of file kstarsdatetime.cpp.

gst()

dms KStarsDateTime::gst

(

)

const

Returns

The Greenwich Sidereal Time The Greenwich sidereal time is the Right Ascension coordinate that is currently transiting the Prime Meridian at the Royal Observatory in Greenwich, UK (longitude=0.0)

Definition at line 167 of file kstarsdatetime.cpp.

GSTtoUT()

QTime KStarsDateTime::GSTtoUT

(

dms

GST

)

const

Convert a given Greenwich Sidereal Time to Universal Time (=Greenwich Mean Time).

GST the Greenwich Sidereal Time to convert to Universal Time.

Definition at line 206 of file kstarsdatetime.cpp.

jdToEpoch()

double KStarsDateTime::jdToEpoch ( long double jd, KStarsDateTime::EpochType type = JULIAN )

static

Takes in a Julian Date and returns the corresponding epoch year in the given system.

Returns

the epoch as a floating-point year value

Parameters

jd	Julian date
type	Epoch system (KStarsDateTime::JULIAN or KStarsDateTime::BESSELIAN)

Definition at line 269 of file kstarsdatetime.cpp.

operator!=()

bool KStarsDateTime::operator!= ( const KStarsDateTime & d ) const

inline

Definition at line 121 of file kstarsdatetime.h.

operator<()

bool KStarsDateTime::operator< ( const KStarsDateTime & d ) const

inline

Definition at line 125 of file kstarsdatetime.h.

operator<=()

bool KStarsDateTime::operator<= ( const KStarsDateTime & d ) const

inline

Definition at line 129 of file kstarsdatetime.h.

operator=()

KStarsDateTime & KStarsDateTime::operator= ( const KStarsDateTime & kdt )

noexcept

Definition at line 27 of file kstarsdatetime.cpp.

operator==()

bool KStarsDateTime::operator== ( const KStarsDateTime & d ) const

inline

Definition at line 117 of file kstarsdatetime.h.

operator>()

bool KStarsDateTime::operator> ( const KStarsDateTime & d ) const

inline

Definition at line 133 of file kstarsdatetime.h.

operator>=()

bool KStarsDateTime::operator>= ( const KStarsDateTime & d ) const

inline

Definition at line 137 of file kstarsdatetime.h.

setDate()

void KStarsDateTime::setDate

(

const QDate &

d

)

Assign the Date according to a QDate object.

d the QDate to assign

Definition at line 144 of file kstarsdatetime.cpp.

setDJD()

void KStarsDateTime::setDJD

(

long double

jd

)

Assign the static_cast<long double> Julian Day value, which includes the time of day encoded in the fractional portion.

jd the Julian Day value to assign.

Definition at line 118 of file kstarsdatetime.cpp.

setFromEpoch() [1/3]

bool KStarsDateTime::setFromEpoch

(

const QString &

e

)

Set the Date/Time from an epoch value, represented as a string.

e the epoch value

Returns

true if date set successfully

See also

epoch()

Definition at line 245 of file kstarsdatetime.cpp.

setFromEpoch() [2/3]

void KStarsDateTime::setFromEpoch

(

double

e

)

Set the Date/Time from an epoch value, represented as a double.

e the epoch value

Note

This method assumes that the epoch 1950.0 is Besselian, otherwise assumes that the epoch is a Julian epoch. This is provided for backward compatibility, and because custom catalogs may still use 1950.0 to mean B1950.0 despite the IAU standard for epochs being Julian.

See also

epoch()

Definition at line 228 of file kstarsdatetime.cpp.

setFromEpoch() [3/3]

bool KStarsDateTime::setFromEpoch	(	double	e,
		EpochType	type )

Set the Date/Time from an epoch value, represented as a double.

e the epoch value

See also

epoch()

Definition at line 236 of file kstarsdatetime.cpp.

setTime()

void KStarsDateTime::setTime

(

const QTime &

t

)

Assign the Time according to a QTime object.

t the QTime to assign

Note

timespec is NOT changed even if the passed QTime has a different timespec than current.

Definition at line 161 of file kstarsdatetime.cpp.

stringToEpoch()

double KStarsDateTime::stringToEpoch ( const QString & eName, bool & ok )

static

Takes in a string and returns a Julian epoch.

Definition at line 288 of file kstarsdatetime.cpp.

Member Data Documentation

B1900

constexpr const double KStarsDateTime::B1900 = 2415020.31352

staticconstexpr

The following values were obtained from Eric Weisstein's world of science: http://scienceworld.wolfram.com/astronomy/BesselianEpoch.html.

Definition at line 250 of file kstarsdatetime.h.

JD_PER_BYEAR

constexpr const double KStarsDateTime::JD_PER_BYEAR = 365.242198781

staticconstexpr

Definition at line 251 of file kstarsdatetime.h.

---

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

• kstarsdatetime.h
• kstarsdatetime.cpp