How much more light gathering power would a telescope with a 50 cm objective lens have than a telescope with a 25cm objective lens?

Answer 1

The light-gathering power of a telescope is directly proportional to the area of its objective lens. The area of a circle is calculated using the formula A = πr^2, where r is the radius of the lens.

For a 50 cm lens, the radius is 25 cm, so the area would be A = π(25)^2 = 625π square cm. For a 25 cm lens, the area would be A = π(12.5)^2 = 156.25π square cm.

Therefore, the telescope with the 50 cm objective lens would have approximately 4 times the light-gathering power of the telescope with the 25 cm objective lens.

Answer 2

Provided that the parabolic shapes of the surfaces of both reflectors are similarly accurate,

the "gains" are proportional to the areas, which also means proportional to the square of

the diameters.

(300m/50m)2 = (6)2 = 36 times more

or the larger reflector has 10log(36) = 15.6 dBmore gain, at any specific wavelength.

Answer 3

"Light gathering power" is simply the result of the area of the lens, and the area

is proportional to the square of the diameter. So the one with twice the diameter

has 4 times the light gathering power.

Answer 4

The so-called "light gathering power" depends on the areaof the telescope's

objective lens or primary mirror, so it varies as the square of the diameter.

5m/0.5m = 10

Light-gathering power of the larger one is (10)2 = 100 times that of the smaller one.

(100 times corresponds to exactly six star magnitudes.)