Question

Arrange the following celestial elements in the correct logical sequence of their study/definition while learning spherical astronomy:
A. Yamya-uttaravrittam (Meridian)
B. Khamadhyam (Zenith)
C. Shanku (Gnomon)
D. Drigvrittam (Vertical Circle)
E. Kshitijavrittam (Horizon)

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

Hint:

Start from the observer (Zenith) $\rightarrow$ Earth (Horizon) $\rightarrow$ Direction (Meridian) $\rightarrow$ Planet (Vertical Circle) $\rightarrow$ Measurement (Shanku).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
To describe the position of a planet, we build a coordinate system step-by-step.

Step 2: Logical Progression:
1. B. Khamadhyam (Zenith): We first define the point directly above the observer.
2. E. Kshitijavrittam (Horizon): Perpendicular to the zenith line, we define the horizon.
3. A. Yamya-uttaravrittam (Meridian): We orient ourselves using the North-South line passing through the zenith.
4. D. Drigvrittam (Vertical Circle): We draw a circle passing through the zenith and the planet to measure its position.
5. C. Shanku (Gnomon/Sine of Altitude): We finally calculate the height (altitude) of the planet along that vertical circle.

Step 3: Final Answer:
The correct logical sequence is B, E, A, D, C.