The lens of human eye has a diameter of `0.8 cm`. How much fainter star can be seen through `508 cm` objective of an astronomical telescope at Mount Polomar in USA ?

Answer

`403,225`

Explanation

Here, `d = 0.8 cm, D = 508 cm`
As light gathering power `prop ("diameter")^2`
`:.` Brightness ratio `beta = (D^2)/(d^2) = ((508)^2)/((0.8)^2) = 403,225`
It amplies that the telescope can see a star `403, 225` times fainter than the faintest star that can be seen with naked eye.