Question

According to the 'Grahalaghava' text, what is the precise numerical measure of the Sun's daily mean motion (Madhyama Gati)?

• A. Nabjaka
• B. Gokshagaja
• C. Goksharthaka
• D. Adryakshaja

Hint:

Sun's motion is always approx 59'. In mnemonic codes, 'Na' (0) often signifies the precision digits. Memorize the 'Nabjaka' code specifically for the Sun in the Grahalaghava context.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Mean motion (Madhyama Gati) is the average angular distance a planet travels in one terrestrial day (24 hours). For the Sun, this motion is approximately 59 minutes and 8 seconds of an arc. In traditional Sanskrit astronomical texts, these values are not written as decimal numbers but are encoded using word-numerals (Bhuta Sankhya) or specific mnemonic systems like 'Katapayadi' to fit the poetic meter of the verses.

Step 2: Detailed Explanation:
The Grahalaghava is famous for simplifying these motions into manageable ratios. The mean motion of the Sun is standardized at 59 minutes, 8 seconds, and 10 thirds (59' 08” 10”').
- The term 'Nabjaka' represents this value in a coded format.
- In the Katapayadi system or the specific nomenclature of the text:
- Na = 0, Bja = 8, Ka = 1. (Representing the fractional parts).
- The Sun's daily motion is nearly one degree ($60'$). The specific term 'Nabjaka' is used in the context of the 'Dhruvas' (constant values) provided in the first chapter of Grahalaghava.

Step 3: Comparison with other options:
The other options like 'Gokshagaja' or 'Adryakshaja' refer to the mean motions or constants for other planets like Mars, Jupiter, or Saturn, or represent different parameters like the planetary revolutions (Bhagana). For instance, 'Go' = 9, 'Ksha' = 5, which often appears in larger planetary constants. However, for the Sun's daily mean motion, 'Nabjaka' is the unique identifier used by Ganesh Daivajna.

Step 4: Final Answer:
The mean motion of the Sun in Grahalaghava is designated by the mnemonic 'Nabjaka'.