Question

How do astronomers measure the diameter of the sun?

Answer 1

Please see below.

Explanation:

One of the easiest way to measure diameter is to use a pinhole camera. But, for this you need a very small hole in, say, a card. This is not easy, but what you can do is to make a bigger whole say `3` `cm.` wide square or a circular hole.

Now a paste a metal film covering it completely. You can use a aluminium foil for this. Now create a very tiny hole in it and place it in sun to form an image as shown below.

Now measure the diameter of image. (better make image on a centimeter graph for accuracy). Also measure the distance of image from pinhole.

The diameter of sun can then be calculated as follows:

`Diametercolor(white)(x)ofcolor(white)(x)sun`

Note that finer the pinhole and larger the distance between pinhole and image, higher the accuracy in measuring diameter.