> But any child can look at the sun (with eye protection :) and see that it is a disc, not a point of light. The disc is about 0.5 degrees, which is not so smal

> But any child can look at the sun (with eye protection :) and see that it is a disc, not a point of light. The disc is about 0.5 degrees, which is not so small. Page 11-12 explicitly discusses "sun-as-a-disk", the resulting shadow penumbra and other sources of inaccuracies.