- Is My Blue Your Blue? (ismy.blue)
People have different names for the colors they see. Language can affect how we memorize and name colors. This is a color naming test designed to measure your personal blue-green boundary.
- Beta Draconis (Wikipedia)
Beta Draconis (β Draconis, abbreviated Beta Dra, β Dra) is a binary star system and the third-brightest star in the northern circumpolar constellation of Draco. The two components are designated Beta Draconis A (officially named Rastaban /ˈræstəbæn/, “head to sole of foot”, the traditional name of the system) and B respectively. With a combined apparent visual magnitude of 2.79, it is bright enough to be easily seen with the naked eye. Based upon parallax measurements from the Hipparcos astrometry satellite, it lies at a distance of about 380 light-years (120 parsecs) from the Sun. The system is drifting closer with a radial velocity of −21 km/s.