date_sun_info

Returns an array with information about sunset/sunrise and twilight begin/end

&reftitle.description; `array` `date_sun_info` `int` `timestamp` `float` `latitude` `float` `longitude`
&reftitle.parameters;

`timestamp`

- Unix timestamp.

`latitude`

- Latitude in degrees.

`longitude`

- Longitude in degrees.

&reftitle.returnvalues;

Returns an array whose structure is detailed in the following list:

`sunrise`

- The timestamp of the sunrise (zenith angle = 90°35').

`sunset`

- The timestamp of the sunset (zenith angle = 90°35').

`transit`

- The timestamp when the sun is at its zenith, i.e. has reached its topmost point.

`civil_twilight_begin`

- The start of the civil dawn (zenith angle = 96°). It ends at `sunrise`.

`civil_twilight_end`

- The end of the civil dusk (zenith angle = 96°). It starts at `sunset`.

`nautical_twilight_begin`

- The start of the nautical dawn (zenith angle = 102°). It ends at `civil_twilight_begin`.

`nautical_twilight_end`

- The end of the nautical dusk (zenith angle = 102°). It starts at `civil_twilight_end`.

`astronomical_twilight_begin`

- The start of the astronomical dawn (zenith angle = 108°). It ends at `nautical_twilight_begin`.

`astronomical_twilight_end`

- The end of the astronomical dusk (zenith angle = 108°). It starts at `nautical_twilight_end`.

The values of the array elements are either UNIX timestamps, &false; if the sun is below the respective zenith for the whole day, or &true; if the sun is above the respective zenith for the whole day.

&reftitle.changelog;

&Version; | &Description;
7.2.0 | The calculation was fixed with regards to local midnight instead of local noon, which changes the results slightly.

&reftitle.examples;

### A `date_sun_info` example

    <?php
    $sun_info = date_sun_info(strtotime("2006-12-12"), 31.7667, 35.2333);
    foreach ($sun_info as $key => $val) {
        echo "$key: " . date("H:i:s", $val) . "\n";
    }
    ?>

&example.outputs;

    sunrise: 05:52:11
    sunset: 15:41:21
    transit: 10:46:46
    civil_twilight_begin: 05:24:08
    civil_twilight_end: 16:09:24
    nautical_twilight_begin: 04:52:25
    nautical_twilight_end: 16:41:06
    astronomical_twilight_begin: 04:21:32
    astronomical_twilight_end: 17:12:00

### Polar night, with some processing

    <?php
    $tz = new \DateTimeZone('America/Anchorage');

    $si = date_sun_info(strtotime("2022-12-21"), 70.21, -148.51);
    foreach ($si as $key => $value) {
        echo
            match ($value) {
                true => 'always',
                false => 'never',
                default => date_create("@{$value}")->setTimeZone($tz)->format( 'H:i:s T' ),
            },
            ": {$key}",
            "\n";
    }
    ?>

&example.outputs;

    never: sunrise
    never: sunset
    12:52:18 AKST: transit
    10:53:19 AKST: civil_twilight_begin
    14:51:17 AKST: civil_twilight_end
    09:01:47 AKST: nautical_twilight_begin
    16:42:48 AKST: nautical_twilight_end
    07:40:47 AKST: astronomical_twilight_begin
    18:03:49 AKST: astronomical_twilight_end

### Midnight sun (Tromsø, Norway)

    <?php
    $si = date_sun_info(strtotime("2022-06-26"), 69.68, 18.94);
    print_r($si);
    ?>

&example.outputs;

    Array
    (
        [sunrise] => 1
        [sunset] => 1
        [transit] => 1656240426
        [civil_twilight_begin] => 1
        [civil_twilight_end] => 1
        [nautical_twilight_begin] => 1
        [nautical_twilight_end] => 1
        [astronomical_twilight_begin] => 1
        [astronomical_twilight_end] => 1
    )

### Calculating length of day (Kyiv)

    <?php
    $si = date_sun_info(strtotime('2022-08-26'), 50.45, 30.52);
    $diff = $si['sunset'] - $si['sunrise'];
    echo "Length of day: ",
        floor($diff / 3600), "h ",
        floor(($diff % 3600) / 60), "s\n";
    ?>

&example.outputs;

    Length of day: 13h 56s