# date_sun_info

(PHP 5 >= 5.1.2, PHP 7, PHP 8)

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

### 说明

date_sun_info(int `$timestamp`, float `$latitude`, float `$longitude`): array

### 参数

`timestamp`

  Unix timestamp.

`latitude`

  Latitude in degrees.

`longitude`

  Longitude in degrees.

### 返回值

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.

### 更新日志

版本 | 说明
--- | ---
7.2.0 | The calculation was fixed with regards to local midnight instead of local noon, which changes the results slightly.

### 示例

示例 #1 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";
}`

以上示例会输出：

    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

示例 #2 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";
}`

以上示例会输出：

    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

示例 #3 Midnight sun (Tromsø, Norway)

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

以上示例会输出：

    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
    )

示例 #4 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";`

以上示例会输出：

    Length of day: 13h 56s

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