Stellarium [0] is such a great project. We even used it in an upper-division college observational astronomy course to perform the historical experiment to meas

Stellarium [0] is such a great project. We even used it in an upper-division college observational astronomy course to perform the historical experiment to measure the Earth-Sun distance (the astronomical unit or au). It was a lot of fun, we mock-observed the transit of Venus [1] from two different latitudes to perform the same calculation done in 1769 on James Cooke's expidition from Tahiti [2]. [0] http://stellarium.org http://stellarium.org [1] https://en.m.wikipedia.org/wiki/Transit_of_Venus https://en.m.wikipedia.org/wiki/Transit_of_Venus [2] https://en.m.wikipedia.org/wiki/1769_Transit_of_Venus_observed_from_Tahiti https://en.m.wikipedia.org/wiki/1769_Transit_of_Venus_observ...