1. What is Local Hour Angle?

Local Hour Angle (LHA) is the angle between the observer's meridian and the hour circle of a celestial body, measured westward along the celestial equator. It is a fundamental concept in celestial navigation and astronomy.

2. How Does the Formula Work?

The calculator uses the Local Hour Angle formula:

Where:

• \( LHA \) — Local Hour Angle (degrees)
• \( LST \) — Local Sidereal Time (hours)
• \( Longitude \) — Observer's longitude (degrees)

Explanation: The formula converts longitude from degrees to hours (dividing by 15, since 15° = 1 hour) and subtracts it from Local Sidereal Time to determine the angular distance of a celestial body from the observer's meridian.

3. Importance of LHA Calculation

Details: LHA is crucial for celestial navigation, astronomical observations, and satellite tracking. It helps determine the position of celestial bodies relative to the observer's location on Earth.

4. Using the Calculator

Tips: Enter Local Sidereal Time in hours and Longitude in degrees. Positive longitude values are east, negative values are west. The result will be in degrees.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of LHA values?
A: LHA typically ranges from 0° to 360°. Values outside this range are usually normalized using modulo 360.

Q2: How is LST different from Local Mean Time?
A: LST is based on the rotation of Earth relative to distant stars, while Local Mean Time is based on the Sun's apparent motion.

Q3: Why divide longitude by 15?
A: Because Earth rotates 15 degrees per hour, converting longitude from degrees to time units (hours).

Q4: Can LHA be negative?
A: Yes, but it's usually converted to a positive value by adding 360 degrees.

Q5: What are practical applications of LHA?
A: Celestial navigation for ships and aircraft, astronomical telescope pointing, and satellite communication systems.