What Is Latitude?

For an observer located in Billings, Montana (latitude 45.8o N, 108.5o W), what would be the angle measure bet?

• For an observer located in Billings, Montana (latitude 45.8o N, 108.5o W), what would be the angle measure between the northern horizon and the north celestial pole? A. 54.2 B. 45.8 C. 44.2 D. 108.5 Also, For an observer located in Billings, Montana (latitude 45.8o N, 108.5o W), what would be the angle measure between the southern horizon and the celestial equator? A. 54.2 B. 45.8 C. 44.2 D. 108.5 An explanation would also be great.

• Answer:

  For an observer in the northern hemisphere (Billings, Montana) the angle between the northern horizon and the northern celestial pole would be the same as the latitude (45.8). This is actually an old navigation trick. Travelers, most commonly sailors, could determine their latitude by locating the north star or north celestial pole and measuring the angle. For the celestial equator, just subtract the latitude from 90 degrees. So 90 - 45.8 = 44.2. This is because the distance between zenith (straight overhead) and the celestial equator is the same as the distance between the north celestial pole and the northern horizon. Since there are 90 degrees between zenith and the southern (or any) horizon, just subtract the latitude from 90.