Hover or tap underlined Spanish terms to see their translation and exam tip.
Las duraciones de los arcos diurno y nocturno de un astro dependen de:The durations of the diurnal and nocturnal arcs of a celestial body depend on:
Show the answer
Correct answer: b) The observer’s latitude and the body’s declination.
Why it is correct
The semi-diurnal arc (meridian angle at rising/setting on the true horizon) is given by cos P = −tan φ · tan δ. Thus the lengths of a body’s diurnal and nocturnal arcs depend solely on the observer’s latitude (φ) and the body’s declination (δ).
Why the others are not
- a) For a given declination, daylight duration varies with the observer’s latitude.
- c) Right ascension shifts when transit occurs, not what fraction of the parallel lies above the horizon.
- d) Neither longitude nor right ascension changes the duration of the diurnal and nocturnal arcs.
How to work it out in the exam
- Duration of diurnal and nocturnal arcs: depends on observer’s latitude (φ) and body’s declination (δ).
Where this question comes from
- Junta de Andalucía · 2023 · 1ª convocatoria · CY Módulo de navegación · question 6 Official paper · Official answer key
Pending instructor review. Machine translation, not reviewed.