Golden hour, accurate to the second.
Anywhere on Earth.
The only ephemerides API that respects elevation. Plan a sunrise shoot at 4 000 m and arrive 17 minutes earlier than everyone else.
Real golden hour
Pre-computed morning and evening windows in your response — no client-side maths from twilight angles.
Elevation correct
Every response uses the elevation-corrected horizon. A ridge at 4 000 m sees sunrise ~17 min before the valley below.
Plan a season ahead
Up to 365-day forecast horizon on Business. Subscribe via iCal feed; your phone calendar stays current.
One call, everything a photo planner needs
curl -H "Authorization: Bearer $THIRDTRAIL_KEY" \
"https://thirdtrail.life/v1/ephemerides/?lat=36.0544&lon=-112.1401&elevation=2134&days=14&tz=America/Phoenix"Grand Canyon South Rim, two-week horizon. Returns sunrise / sunset, transit (solar noon), the four twilight phases and golden-hour and blue-hour windows for every day in the response.
Response excerpt:
{
"days": [
{
"date": "2026-06-21",
"sun": {
"rise": "2026-06-21T05:14:33-07:00",
"set": "2026-06-21T19:43:08-07:00",
"transit": "2026-06-21T12:28:51-07:00",
"golden_hour": {
"morning_start": "2026-06-21T05:14:33-07:00",
"morning_end": "2026-06-21T05:53:42-07:00",
"evening_start": "2026-06-21T19:04:06-07:00",
"evening_end": "2026-06-21T19:43:08-07:00"
},
"blue_hour": { "..." }
}
}
]
}Why photographers care about elevation
| Location | Sunrise (sea level) | Sunrise (actual elevation) | Difference |
|---|---|---|---|
| Mauna Kea summit (4 207 m) | 06:00:00 | 05:43:00 | 17 min earlier |
| Mont Blanc summit (4 808 m) | 06:00:00 | 05:41:30 | 18.5 min earlier |
| Grand Canyon S Rim (2 134 m) | 06:00:00 | 05:48:30 | 11.5 min earlier |
| Skellig Michael (218 m) | 06:00:00 | 05:56:24 | 3.6 min earlier |
Calculated for clear-sky conditions; actual ground-truth horizon may add seconds depending on local terrain. The reason is geometric horizon dip: from altitude h, the horizon drops by arccos(R / (R + h)) below the standard horizontal — roughly 1.7°√h(km).
How it compares
| thirdtrail | sunrise-sunset.org | PhotoPills | Roll your own | |
|---|---|---|---|---|
| Elevation-corrected horizon | ✅ | — | — | ~600 LOC of correctness traps |
| Pre-computed golden / blue hour | ✅ | — | app only | derive client-side |
| iCal feed | ✅ | — | app only | build it |
| 365-day forecast horizon | ✅ (Business) | — | app only | — |
| Webhooks (event triggers) | ✅ (Pro+) | — | — | build it |
Start using it
Free tier: 100 calls/day, 7-day forecast horizon. No credit card required.