1. What is Twilight?

Twilight is the time between dawn and sunrise or between sunset and dusk, when sunlight is scattered in the upper atmosphere, illuminating the lower atmosphere. There are three types of twilight defined by how far the sun is below the horizon.

2. How Does the Calculator Work?

The calculator determines when the sun reaches specific altitudes below the horizon:

Explanation: The calculations are based on astronomical algorithms that account for the observer's location, date, and the sun's position.

3. Importance of Twilight Calculation

Details: Twilight times are important for aviation, photography, military operations, and religious observances. Different activities require different levels of darkness.

4. Using the Calculator

Tips: Enter your latitude (-90 to 90°), longitude (-180 to 180°), and the date. The calculator will show the times for each twilight phase and sunrise.

5. Frequently Asked Questions (FAQ)

Q1: Why are there different types of twilight?
A: The different types correspond to different levels of darkness needed for various activities (civil = general outdoor activities, nautical = sea navigation, astronomical = astronomy).

Q2: How does latitude affect twilight duration?
A: Near the poles, twilight can last for weeks during certain seasons, while at the equator it's much shorter (about 1 hour).

Q3: What time standard is used?
A: Times are calculated in local solar time. For precise local clock time, timezone and daylight saving adjustments would be needed.

Q4: Why don't I get astronomical twilight results sometimes?
A: In summer at high latitudes, the sun may never reach -18°, so astronomical twilight doesn't occur.

Q5: How accurate are these calculations?
A: They're generally accurate to within a minute for most locations, though local topography can affect actual visibility.