This website, created by scientist David Harper and webmaster and mathematician Lynne Stockman, offers interactive modules about the sun, moon, and Earth. Users can calculate the distance between any two locations on Earth and determine latitudes and longitudes. The site displays the phases of the moon and lists the occurrences of eclipses. Visitors can learn about Blue Moons and when they are expected to occur. Although this site describes itself as being visually appealing without depending on any particular type of software or hardware so that it is viewable on any browser, Java is needed to convert between OSGB (the British National Grid), OSNI (the Irish Grid), and latitude/longitude.