Lunar occultation is a method for finding the radius of a star. The idea is to measure how long it takes for the moon to cover the star as the moon passes in front of the star.
(1) The moon makes a full revolution around the earth in 27 days. Show that the angular speed of the moon is 2.7×10−6 rad s-1.
(2) A star is covered by the moon in 17 ms. What is the angular diameter of the star?
(3) The parallax of the star is 0.167 arcsec. What is the radius of the star?