1. The problem statement, all variables and given/known data A sailor somewhere on the Pacific Ocean uses a navigational instrument to measure the altitude of the star Aldebaran (α Tauri, the brightest star in the constellation Taurus, the Bull) at the moment that Aldebaran is due south of the zenith. The equatorial coordinates of Aldebaran are α = 4h 36m 12s, δ = +16°31', and the sailor measures Aldebaran's altitude as 73° 51'. a.What is the sailor's latitude? b.For what range of declinations would stars be circumpolar as seen by this sailor? c. Where would the sailor need to stand so that i. all stars visible in the sky are circumpolar? ii. Aldebaran passes through the sailor's zenith? 2. Relevant equations Nothing particular relevant 3. The attempt at a solution a. I've seen many formulas for calculation latitude so I'm not sure which is correct. Any ideas? b. Basically the range would be Dec >90-latitude? c. i. The celestial equator? ii. This one I have no idea, would it be the same longitude that corresponds to it's Right Ascension?