API Reference

getSpa

SpaResult getSpa(
  DateTime date,
  double latitude,
  double longitude,
  double timezone, {
  double elevation = 0,
  double pressure = 1013,
  double temperature = 15,
  double deltaT = 67,
  List<double> customAngles = const [],
})

Computes solar position for a given location and moment.

Parameters

Parameter	Type	Default	Description
`date`	`DateTime`	required	UTC date and time
`latitude`	`double`	required	Degrees (-90 to 90)
`longitude`	`double`	required	Degrees (-180 to 180)
`timezone`	`double`	required	Hours from UTC
`elevation`	`double`	0	Meters above sea level
`pressure`	`double`	1013	Atmospheric pressure (mbar)
`temperature`	`double`	15	Temperature (Celsius)
`deltaT`	`double`	67	TT - UT1 (seconds)
`customAngles`	`List<double>`	[]	Zenith angles for custom rise/set computation

SpaResult fields

Field	Type	Description
`zenith`	`double`	Solar zenith angle (degrees)
`azimuth`	`double`	Solar azimuth angle (degrees, clockwise from north)
`sunrise`	`double`	Sunrise in fractional hours (local time)
`solarNoon`	`double`	Solar noon in fractional hours (local time)
`sunset`	`double`	Sunset in fractional hours (local time)
`angles`	`List<SpaAngleResult>`	Rise/set pairs for each entry in `customAngles`

SpaAngleResult fields

Field	Type	Description
`zenith`	`double`	The requested zenith angle
`sunrise`	`double`	Rise time in fractional hours for this zenith
`sunset`	`double`	Set time in fractional hours for this zenith

Custom zenith angles

Pass any solar zenith angles to get rise/set times at those angles. Standard civil/nautical/astronomical twilight angles are 96, 102, and 108 degrees respectively. Prayer time implementations use this to calculate Fajr and Isha.

final result = getSpa(
  DateTime.utc(2024, 3, 15, 12, 0, 0),
  40.7128, -74.0060, -5.0,
  customAngles: [96.0, 102.0, 108.0],
);

for (final angle in result.angles) {
  print('${angle.zenith}: rise ${angle.sunrise}, set ${angle.sunset}');
}

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