Latitude determination – altitude of key polar references For an observer anywhere on Earth, the latitude of the station equals the altitude of which of the following celestial references?

Introduction / Context:
Classical latitude determination in surveying relies on the altitude of the celestial pole. In the northern hemisphere, this is approximated by the altitude of Polaris; in the southern hemisphere, the south celestial pole is used via suitable star patterns.

Given Data / Assumptions:

• Latitude φ is measured from the equator to the observer's position.
• Altitude is measured upward from the horizon to an object on the celestial sphere.
• Polaris lies close to the north celestial pole (small offset ignored for conceptual understanding).

Concept / Approach:
The altitude of the celestial pole above the horizon equals the observer's latitude. In practice, observing Polaris yields approximately the same angle for northern observers. Conceptually, one may think of the terrestrial pole projected to the sky; its altitude is likewise φ.

Step-by-Step Solution:
Recognize the sky's apparent rotation around the celestial poles.At your location, the pole's altitude equals your latitude φ.Hence measuring Polaris altitude (north) or equivalent methods (south) gives φ.

Verification / Alternative check:
At the equator (φ = 0°), the pole lies on the horizon (altitude 0°). At the pole (φ = 90°), the celestial pole is at the zenith (altitude 90°). This matches observations.

Why Other Options Are Wrong:
Each listed reference is effectively describing the same polar direction; therefore the combined option is correct.

Common Pitfalls:
Neglecting the small offset of Polaris from the true pole; precise work applies a correction, but the principle remains.

Final Answer:
All the above