In this article, the authors describe their use of simultaneous observations of the 2016 transit of Mercury made from two widely separated locations on Earth to determine the distance to the Sun in a way different from that suggested in 1715 by Halley. Using an internet link, teachers and students can make a similar derivation at the 2019 transit of Mercury also based on parallax and requiring only a set of measurements at one agreed-upon instant of time. They did not compare timing of the contacts (Halley's method), which groups did for the 2012 transit of Venus.