An astronomer is studying a particular nebula in interstellar space using a reflecting telescope. The telescope has an objective aperture diameter of D₁ = 290 mm and focal length of fo,1 = 1,900 mm. The telescope captures the nebula's image on photographic film at its prime focus with an exposure time of At₁ = 1.75 min. If the astronomer wants to produce the same light energy per unit area on the film, what should be the exposure time (in minutes) to photograph the same nebula with a smaller telescope, which has an objective with diameter D₂ = 60.0 mm diameter and a focal length f0,2 = 900 mm? min

An astronomer is studying a particular nebula in interstellar space using a reflecting telescope. The telescope has an objective aperture diameter of D₁ = 290 mm and focal length of fo,1 = 1,900 mm. The telescope captures the nebula's image on photographic film at its prime focus with an exposure time of At₁ = 1.75 min. If the astronomer wants to produce the same light energy per unit area on the film, what should be the exposure time (in minutes) to photograph the same nebula with a smaller telescope, which has an objective with diameter D₂ = 60.0 mm diameter and a focal length f0,2 = 900 mm? min