Question

How can the diameter of the sun be determined?

Answer 1

From the angular spacing of the right-above-head solar disc and the distance of the Sun.

Explanation:

If the angular spacing is `alpha` and the distance of the observer from the Sun is`1 AU -6378 km=149597871-6378 = 149591493 km`,

the diameter = 2 X 149591493 X tan `(alpha/2)` km-

The compatible data are `alpha = 0.5334^o` and 5-sd diameter = 1392600 km.

The precision depends on the precision in `alpha`. It is just 4-sd approximation for `alpha`.So, answer is reliable up to 4 or 5 sd only.