Astro v0.1.0 Astro View Source
Functions for basic astronomical observations such as sunrise, sunset, solstice, equinox, moonrise, moonset and moon phase.
Link to this section Summary
Functions
Calculates the sunrise for a given location and date.
Calculates the sunset for a given location and date.
Link to this section Types
date()
View Sourcedate() :: Calendar.date() | Calendar.naive_datetime() | Calendar.datetime()
location()
View Sourcelocation() :: {longitude(), latitude()} | Geo.Point.t() | Geo.PointZ.t()
Link to this section Functions
sunrise(location, date, options \\ default_options())
View Sourcesunrise(location(), date(), options()) :: {:ok, DateTime.t()} | {:error, :time_zone_not_found | :no_time}
Calculates the sunrise for a given location and date.
Sunrise is the moment when the upper limb of the sun appears on the horizon in the morning.
Arguments
location
is the latitude, longitude and optionally elevation for the desired sunrise time. It can be expressed as:{lng, lat}
- a tuple with longitude and latitude as floating point numbers. Note the order of the arguments.- a
Geo.Point.t
struct to represent a location without elevation - a
Geo.PointZ.t
struct to represent a location and elevation
date
is aDate.t
,NaiveDateTime.t
orDateTime.t
to indicate the date of the year in which the sunrise time is required.options
is a keyword list of options.
Options
solar_elevation
represents the type of sunrise required. The default is:geometric
which equates to a solar elevation of 90°. In this case the calulation also accounts for refraction and elevation to return a result which accords with the eyes perception. Other solar elevations are::civil
representing a solar elevation of 96.0°. At this point the sun is just below the horizon so there is generally enough natural light to carry out most outdoor activities.:nautical
representing a solar elevation of 102.0° This is the point at which the horizon is just barely visible and the moon and stars can still be used for navigation.:astronomical
representing a solar elevation of 108.0°. This is the point beyond which astronomical observation becomes impractical.Any floating point number representing the desired solar elevation.
:time_zone
is the time zone to in which the sunrise is requested. The default is:default
in which the sunrise time is reported in the time zone of the requested location. Any other time zone name supported by the option:time_zone_database
is acceptabe.:time_zone_database
represents the module that implements theCalendar.TimeZoneDatabase
behaviour. The default isTzdata.TimeZoneDatabase
.
Returns
a
DateTime.t
representing the time of sunrise in the requested timzone at the requested location or{:error, :time_zone_not_found}
if the requested time zone is unknown{:error, :no_time}
if for the requested date and location there is no sunrise. This can occur at very high latitudes during summer and winter.
Examples
# Sunrise in Sydney, Australia
Astro.sunrise({151.20666584, -33.8559799094}, ~D[2019-12-04])
{:ok, #DateTime<2019-12-04 05:37:00.000000+11:00 AEDT Australia/Sydney>}
# Sunrise in Alert, Nanavut, Canada
Astro.sunrise({-62.3481, 82.5018}, ~D[2019-12-04])
{:error, :no_time}
sunset(location, date, options \\ default_options())
View Sourcesunset(location(), date(), options()) :: {:ok, DateTime.t()} | {:error, :time_zone_not_found | :no_time}
Calculates the sunset for a given location and date.
Sunset is the moment when the upper limb of the sun disappears below the horizon in the evening.
Arguments
location
is the latitude, longitude and optionally elevation for the desired sunrise time. It can be expressed as:{lng, lat}
- a tuple with longitude and latitude as floating point numbers. Note the order of the arguments.- a
Geo.Point.t
struct to represent a location without elevation - a
Geo.PointZ.t
struct to represent a location and elevation
date
is aDate.t
,NaiveDateTime.t
orDateTime.t
to indicate the date of the year in which the sunset time is required.options
is a keyword list of options.
Options
solar_elevation
represents the type of sunset required. The default is:geometric
which equates to a solar elevation of 90°. In this case the calulation also accounts for refraction and elevation to return a result which accords with the eyes perception. Other solar elevations are::civil
representing a solar elevation of 96.0°. At this point the sun is just below the horizon so there is generally enough natural light to carry out most outdoor activities.:nautical
representing a solar elevation of 102.0° This is the point at which the horizon is just barely visible and the moon and stars can still be used for navigation.:astronomical
representing a solar elevation of 108.0°. This is the point beyond which astronomical observation becomes impractical.Any floating point number representing the desired solar elevation.
:time_zone
is the time zone to in which the sunset is requested. The default is:default
in which the sunset time is reported in the time zone of the requested location. Any other time zone name supported by the option:time_zone_database
is acceptabe.:time_zone_database
represents the module that implements theCalendar.TimeZoneDatabase
behaviour. The default isTzdata.TimeZoneDatabase
.
Returns
a
DateTime.t
representing the time of sunset in the requested time zone at the requested location or{:error, :time_zone_not_found}
if the requested time zone is unknown{:error, :no_time}
if for the requested date and location there is no sunset. This can occur at very high latitudes during summer and winter.
Examples
# Sunset in Sydney, Australia
Astro.sunset({151.20666584, -33.8559799094}, ~D[2019-12-04])
{:ok, #DateTime<2019-12-04 19:53:00.000000+11:00 AEDT Australia/Sydney>}
# Sunset in Alert, Nanavut, Canada
Astro.sunset({-62.3481, 82.5018}, ~D[2019-12-04])
{:error, :no_time}