Hover or tap underlined Spanish terms to see their translation and exam tip.
En la mar, se toma con la alidada del compás el ángulo formado entre el Norte y Dubhe, ¿qué es lo que hemos obtenido?At sea, if we measure with the compass azimuth ring (alidada) the horizontal angle between North and the star Dubhe, what have we obtained?
Show the answer
Correct answer: a) The azimuth.
Why it is correct
The horizontal angle measured around the horizon from North to the vertical circle of a celestial body (such as Dubhe) using a compass azimuth sight vane is, by definition, the body’s azimuth (compass azimuth when read off the compass card).
Why the others are not
- b) Greenwich hour angle is an equatorial arc obtained from the Almanac using UT.
- c) Local hour angle is measured along the celestial equator from the observer’s upper meridian.
- d) Sidereal hour angle is measured along the celestial equator from the First Point of Aries.
How to work it out in the exam
- Horizontal angle measured from North to a star with a compass sight vane = azimuth.
Where this question comes from
- Ministerio de Transportes (Madrid) · 2022 · Convocatoria de junio · CY Test 1 · question 3 Official paper · Official answer key
- Ministerio de Transportes (Madrid) · 2022 · Convocatoria de junio · CY Test 2 · question 10 Official paper · Official answer key
Pending instructor review. Machine translation, not reviewed.