The north celestial pole appears 30° above your horizon.The star Vega is on your meridian.By studying your star charts and your clocks,you determine that Vega crossed the meridian in Greenwich (England)3 hours ago.Where are you?
A)latitude 30°N,longitude 45° west
B)latitude 30°N,longitude 3° west
C)latitude 60°N,longitude 45° west
D)It is not possible to determine your longitude from the information given.

Question

Quizplus · Accepted Answer

The north celestial pole's altitude above the horizon is equal to the observer's latitude, so a 30° altitude indicates a latitude of 30°N. The time difference between the local meridian crossing of Vega and its crossing in Greenwich (3 hours) corresponds to a difference in longitude, as the Earth rotates 15° per hour. Thus, 3 hours x 15°/hour = 45° west.

The North Celestial Pole Appears 30° Above Your Horizon