Day Lab Part 1: Determine the Angular Size of the Sun

We can measure the sun's angular diameter by recording the time that it takes the sun to move through its own diameter.  We can do this by marking the two edges of the sum on a piece of paper after focusing the sun through a lens, and measuring the time that it takes for the sun to move entirely across the line.

This is what the data measurement procedure looked like:

 This is what we where actually measuring:

The average time for the sun to move through its own diameter was 2:11.14 or 2 minutes and 11.14 seconds.

It's time to do some math.

There are 24 hours in a day, so the sun moves through 360 degrees in 24 hours.

\[\frac{t_{diameter}}{\theta_{diameter}}=\frac{t_{orbit}}{\theta_{orbit}}\]

\[\theta_{diameter}=\frac{t_{diameter}\times \theta_{orbit}}{t_{orbit}}\]

\[\theta_{diameter}=\frac{2:11.14 \times 360^{\circ} }{24:00:00}\]

\[\theta_{diameter}=\boxed{0.55^{\circ}} \]

Therefore, the angular diameter of the sun as viewed form Earth or 1 AU, is 0.55 degrees. 

I worked with the Tuesday 1:00PM lab group to do this experiment.