Question

The 'Dakshinagolarambha' (Beginning of the Southern celestial hemisphere) occurs when the Sun reaches which point?

• A. Sayana Karka (Summer Solstice)
• B. Sayana Tula (Autumnal Equinox)
• C. Sayana Mesha (Vernal Equinox)
• D. Sayana Makara (Winter Solstice)

Hint:

Gola = Hemisphere. Hemisphere depends on the Equator. The Sun crosses the Equator at the Equinoxes. Moving South at Equinox = Tula.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The celestial sphere is divided into two hemispheres by the celestial equator: the Northern Hemisphere (Uttara Gola) and the Southern Hemisphere (Dakshina Gola). It is important to distinguish between 'Ayana' (Northward/Southward motion) and 'Gola' (Position North or South of the equator).

Step 2: Detailed Explanation:
1. Uttara Gola: Starts when the Sun crosses the celestial equator moving North. This is the Vernal Equinox (Sayana Mesha).
2. Dakshina Gola: Starts when the Sun crosses the celestial equator moving South. This happens at the Autumnal Equinox (Sayana Tula). From this point onwards, the Sun's declination becomes South (negative).

Step 3: Distinguishing from Ayana:
- Dakshinayana (Southward journey) starts at the Summer Solstice (Sayana Karka). However, for the first three months of Dakshinayana, the Sun is still in the Northern Hemisphere (declination is positive but decreasing).
- The Sun only enters the Southern Hemisphere (Dakshina Gola) when it crosses the equator at Tula.

Step 4: Final Answer:
The beginning of the Southern hemisphere (Dakshinagolarambha) is at Sayana Tula.