Hertzsprung-Russell Diagram

  • Stars

    FAS Astronomers Blog, Volume 30, Number 5. Stars are huge balls of hydrogen plasma powered by nuclear fusion reactions at their core. Stellar Distances Except for the Sun, which is 93 million miles away, stars are a vast distance from us. Therefore, it isn’t always practical to measure these distances in miles, so astronomers use…

  • Observing the Stars

    Young Astronomers Blog, Volume 29, Number 17. After becoming familiar with the Night Sky and observing the Moon and planets, you might try to find a few stars. You will notice that some stars can have several names. The brighter stars in the night sky usually have proper names such as Betelgeuse, Vega, Rigel, and…

  • Betelgeuse is Dimming

    Young Astronomers Blog, Volume 28, Number 2. Astronomers measure the magnitude of a star in a bit of a strange way that dates to Hipparchus. A negative magnitude is brighter than a positive magnitude. A difference of one magnitude is actually a 2.5 times difference in brightness. A star’s apparent magnitude is the perceived magnitude…