Taylor's thesis work was on lunar occultation measurements. Juno was the first asteroid for which an occultation was observed. Existence of the atmosphere of Pluto was proven via stellar occultation. The International Occultation Timing Association recorded no observations at all. Syzygy sometimes results in an occultation, transit, or eclipse. An occultation of Venus by the Moon was visible from some locations. A similar kink was observed during stellar occultation in 1988. Major GNSS radio occultation missions include the GRACE, CHAMP, and COSMIC. Typically the occultation of the hotter star causes the primary eclipse. In this way, a solar eclipse is an occultation of the Sun. The last occultation of Regulus by a planet was on July 7, 1959, by Venus. Sunnis in general reject the Twelver Shi'ite principle of the Mahdi's occultation. The next occultation of Mercury by Venus will be on December 3, 2133. They introduced the doctrines of Occultation (Ghayba) and Return (Raj'a) of the Mahdi. Another evidence of the haze was obtained in 2002 due to a new occultation.