i have an astronamy class but its a math problem ?

Question

Earth's rotational axis precesses with a period of 26,000 years, tracing out a circle in the sky. Currently Polaris marks the location of the north celestial pole (NCP). How long until Alderamin, the brightest star in the constellation Cepheus (roughly 70° from Polaris along the circle), becomes the new North Star?

( ) years.

Answer 1

Ω = precession rate = 360°/(26,000 years)

 

You need to precess by 70° to align the star with the North Star position.

 

Ωt = 70°

 

Solve for t.

 

t = 70°/Ω = 70° / [360°/(26,000 years)] ≅ 5055.6 years