Astronomical Sunrise (ex. 4:41 am)
- The Sun is 18° below the horizon.
- The first very faint light becomes visible, but the sky is still mostly dark.
- Not visible to the naked eye in city lights — astronomers use this to know when the sky is truly dark.
Nautical Sunrise (ex. 5:09 am)
- The Sun is 12° below the horizon.
- Some light appears; horizon becomes faintly visible.
- Traditionally used by sailors for navigation (hence “nautical”).
Civil Sunrise (ex. 5:37 am)
- The Sun is 6° below the horizon.
- Enough light for most outdoor activities without artificial lighting.
- Streetlights are usually turned off around this time.
Official Sunrise (ex. 6:01 am)
- The upper edge of the Sun becomes visible above the horizon.
- This is the “normal sunrise” we refer to in daily life.
Transit (ex. 12:18 pm)
- The Sun crosses the local meridian (highest point in the sky for the day).
- Often close to “solar noon”, which can differ from 12:00 on the clock due to longitude and time zone.
Official Sunset (ex. 6:36 pm)
- The upper edge of the Sun disappears below the horizon.
- This is the “normal sunset”.
Civil Sunset (ex. 7:00 pm)
- The Sun is 6° below the horizon.
- Still bright enough for outdoor activity without lights.
- After this, artificial lighting is usually needed.
Nautical Sunset (ex. 7:28 pm)
- The Sun is 12° below the horizon.
- Horizon is no longer visible at sea — sailors traditionally used this limit.
- Sky is darkening rapidly.
Astronomical Sunset (ex. 7:57 pm)
- The Sun is 18° below the horizon.
- The sky is fully dark — good for astronomers to observe faint stars, galaxies, etc.
Day Length: 12h 35m → From Official Sunrise to Official Sunset.
Night Length: 11h 24m → The rest of the time (24h minus day length).
Note - This example data is based on date Sep 6, 2025 and location New Delhi, India.