An amplitude of the Sun in high latitudes...

🔍 Key Concepts

• Amplitude as used in navigation is the Sun’s bearing when its center is on the visible horizon • How refraction and dip of the horizon change when the Sun is above vs. exactly on the horizon • Why using the Sun’s center (not just a limb) on the visible horizon is important in high latitudes

💭 Think About

• Ask yourself: At what vertical position of the Sun does refraction change most rapidly, and how would that affect an amplitude observation? • Consider which choice describes a condition that is clearly and repeatably identifiable on the horizon, even in high latitudes where twilight is long. • Think about standard sight‑reduction practice: when we define sunrise/sunset times or amplitudes, do we conceptually use the Sun’s limb or its center for the geometric definition?

✅ Before You Answer

• Verify which option explicitly mentions the Sun’s center on the visible horizon, not just ‘above’ or a specific limb. • Check which condition would minimize errors from refraction, which is greatest when the Sun is just below or just breaking the horizon. • Confirm which description best matches the textbook definition of an amplitude observation used to find compass error.

An amplitude of the Sun in high latitudes __________.

should only be observed when the Sun's lower limb is above the horizon

is most accurate before sunrise

is most accurate after sunset

is most accurate when the Sun's center is observed on the visible horizon

🔍 Key Concepts

💭 Think About

✅ Before You Answer