Sunrise 3.0
Note
This service is currently in beta, but no large changes are expected before going into production.
Data format
Properties
| Body | Name | Description |
|---|---|---|
| Sun | sunrise | when the upper limb of the sun becomes visible over the horizon¹ |
| Sun | sunset | when the upper limb of the sun no longer is visible over the horizon¹ |
| Sun | solarnoon | when the moon centre crosses the meridian |
| Sun | solarmidnight | when the moon centre crosses the antimeridian |
| Moon | moonrise | when the upper limb of the moon becomes visible over the horizon² |
| Moon | moonset | when the upper limb of the moon no longer is visible over the horizon² |
| Moon | high_moon | when the moon centre crosses the meridian |
| Moon | low_moon | when the moon centre crosses the antimeridian |
| - | azimuth | horizontal angle from north to the horizontal component of the disc centre angle from the horizon |
| Moon | phase | degrees, 0 being new moon and 180 being full moon |
Note 1: Technically defined as when the sun is 0.8333 degrees below the horizon. This is an approximation given the average apparent radius of the sun and average refraction (both which can vary slightly due to irregular planetary orbits and atmospheric conditions).
Note 2: Computation of moonrise/set is more complicated than for the sun, as the apparent size of the moon varies since the orbit is not perfectly circular. For simplicity we have chosen a constant value of 34 arcminutes (0.5666 degrees) for atmospheric refraction and an averaged moon radius of 16 arcminutes (0.2667 degrees). For more information, see the US Naval Observatory.
Moon phases
| Degrees | Descripton |
|---|---|
| 0 | New moon |
| 0..90 | Waxing crescent |
| 90..180 | Waxing gibbous |
| 180 | Full moon |
| 180..270 | Waning gibbous |
| 270..360 | Waning crescent |
Example outputs
Sun
{
"type" : "Feature",
"copyright" : "MET Norway",
"licenseURL" : "https://api.met.no/license_data.html",
"geometry" : {
"coordinates" : [
10.716667,
59.933333
],
"type" : "Point"
},
"when" : {
"interval" : [
"2022-12-17T23:17:00Z",
"2022-12-18T23:17:00Z"
]
},
"properties" : {
"body" : "Sun",
"solarmidnight" : {
"disc_centre_elevation" : -53.47,
"time" : "2022-12-19T00:13+01:00",
"visible" : false
},
"solarnoon" : {
"disc_centre_elevation" : 6.67,
"time" : "2022-12-18T12:13+01:00",
"visible" : true
},
"sunrise" : {
"azimuth" : 140.12,
"time" : "2022-12-18T09:16+01:00"
},
"sunset" : {
"azimuth" : 219.87,
"time" : "2022-12-18T15:10+01:00"
}
}
}
Moon
{
"copyright": "MET Norway",
"licenseURL": "https://api.met.no/license_data.html",
"type": "Feature",
"geometry": {
"type": "Point",
"coordinates": [
10.716667,
59.933333
]
},
"when": {
"interval": [
"2022-12-17T23:17:00Z",
"2022-12-18T23:17:00Z"
]
},
"properties": {
"body": "Moon",
"moonrise": {
"time": "2022-12-18T02:01+01:00",
"azimuth": 98.49
},
"moonset": {
"time": "2022-12-18T13:01+01:00",
"azimuth": 255.99
},
"high_moon": {
"time": "2022-12-18T07:41+01:00",
"disc_centre_elevation": 23.89,
"visible": true
},
"low_moon": {
"time": "2022-12-18T20:03+01:00",
"disc_centre_elevation": -39.17,
"visible": false
},
"moonphase": {
"value": 288.54
}
}
}
Additional notes
Calculating the sun and moon elevations
As the sun elevation describes an almost perfect sine curve on the sky, the position at a given time can be calculated from the four fixed points given in the sunrise, solarnoon, sunset and solarmidnight elements. Similarly, the moonrise, high_moon, moonset and low_moon elements can be used to calculate moon elevation. If any of the elements are missing, it means the object is not visible or does not go below the horizon.
You can download a PDF document explaining the formulas in detail.
Sources
Sunrise 3 uses the Skyfield Python library for the calculations. If you have more advanced needs than is covered by this service we recommend downloading this or a similar library and do your calculations locally.