Question

What is the technical term for the longitudinal difference between two places on Earth used for time correction in Jyotish?

• A. Rēkhāntara
• B. Dēśāntara
• C. Akṣāṃśa
• D. Paramakrānti

Hint:

Remember: Deshantara = Longitude correction (Time). Akshansha = Latitude (Shadow). Deshantara is essential to convert 'Universal/Standard' planetary positions to 'Local' ones.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
All ancient Indian astronomical calculations were initially done for a standard meridian, which passed through Lanka (on the equator) and Ujjain. Since every place is at a different longitude, the planetary positions and the time of events must be corrected for the specific location. This correction based on longitude is called 'Dēśāntara'.

Step 2: Detailed Explanation:
1. Dēśāntara: 'Dēśa' means place/country and 'Antara' means difference. It is the distance in 'Yōjanas' (ancient unit of distance) between the observer's place and the Prime Meridian. Because the Earth rotates, this distance translates into a time difference.
2. Calculation: The circumference of the Earth at a particular latitude is determined. The distance of the place from the meridian is measured. The ratio of this distance to the circumference determines the amount of time (in Ghaṭis/Palas) to be added or subtracted from the standard 'Madhyama' (mean) planetary positions.
3. Distinction from other terms:
- Akṣāṃśa: This is Latitude (distance from the equator). It is used for shadow calculations (Palabha) but not for the primary longitude time offset.
- Paramakrānti: This is the maximum declination of the Sun (Obliquity of the ecliptic), usually taken as \( 24^\circ \) in ancient texts.
- Rēkhāntara: While 'Rekha' refers to the meridian line, the standard term for the *correction* factor or the *difference* in longitude itself in the context of Surya Siddhanta is Dēśāntara.

Without Dēśāntara, the 'Tithi' or 'Nakṣatra' end-times would be the same for everyone in the world, which is scientifically incorrect. Every 1 degree of longitude results in a 4-minute difference in local time. Ancient Indian astronomers calculated this by finding the 'distance on the earth' and applying it to the daily motion of the planets.

Step 3: Final Answer:
The difference between two places is called Dēśāntara.