Monday, August 18, 2014

The First Planetary Nebula Spectrum

Sky and Telescope has an article "The First Planetary Nebula Spectrum." 150 years ago this month was the first time anyone had take spectrum of a planetary nebula.

At the time the word "nebula" covered a variety of objects that were visible in telescopes, but whose composition was not understood. The observed spectrum gave important clues about one type of nebula, namely the planetary nebula.

See this link....