Question

In the study of 'Gōla' (Spherical Astronomy), into which two primary 'Gōlas' (Hemispheres) is the celestial sphere divided based on the Sun's declination?
A. Pūrvagōla
B. Paścimagōla
C. Uttaragōla
D. Dakṣiṇagōla

• A. Only A, C
• B. Only B, D
• C. Only D, E
• D. Only C, D

Hint:

Gola = Sphere/Hemisphere. In Astronomy, the "Middle" is the Equator. Everything North is Uttara, everything South is Dakshina. East and West are daily motions, not seasonal Golas.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The term 'Gōla' refers to a sphere. In the context of astronomical geography and spherical geometry, the celestial sphere is bisected by the celestial equator (Nāḍī-vr̥tta). This division creates two hemispheres based on the North and South celestial poles. The Sun spends half the year in each hemisphere.

Step 2: Detailed Explanation:
1. Uttaragōla (C): This is the Northern Hemisphere of the celestial sphere. When the Sun is at a positive declination (North of the equator), it is said to be in Uttaragōla. This period starts from the Vernal Equinox (Mēṣa Saṃkrānti in the Sāyana system) and lasts until the Autumnal Equinox. In this hemisphere, the Sun rises North of East and remains above the horizon for more than 12 hours for observers in the Northern Hemisphere.

2. Dakṣiṇagōla (D): This is the Southern Hemisphere of the celestial sphere. When the Sun's declination is negative (South of the equator), it is in Dakṣiṇagōla. This period starts from the Autumnal Equinox (Tulā Saṃkrānti) and lasts until the Vernal Equinox. During this time, the days are shorter than the nights in the Northern Hemisphere.

Difference from Ayanas: While Ayanas (Uttarāyana/Dakṣiṇāyana) refer to the *direction* of the Sun's motion (moving Northward or Southward), Gōlas refer to the Sun's *position* relative to the Equator.
- Pūrvagōla (A) and Paścimagōla (B): These terms refer to the Eastern and Western halves of the sky relative to the observer's meridian (the line passing through the Zenith). While they are used in certain astronomical calculations (like Dr̥k-karma), they are not the primary standard 'Gōlas' used to define the seasonal and declination-based halves of the solar year.

The study of 'Gōladhyāya' in texts like Siddhānta Śirōmaṇi is dedicated to explaining these spherical divisions. Understanding Uttaragōla and Dakṣiṇagōla is crucial for calculating the 'Lagna' (Ascendant) and the 'Cara' (ascensional difference) for any given latitude.

Step 3: Final Answer:
The two primary hemispheres are Uttaragōla and Dakṣiṇagōla (C and D).