A team of professional and amateur astronomers has succeeded in observing a distant companion as it eclipsed the bright variable star b Persei (not to be confused with Beta Persei) in a rare event.
The b Persei system was already known as a binary, with two stars that orbit each other every 1.5 days. But a suspected third companion popped up during a survey of radio-emitting stars. The Navy Precision Optical Interferometer (NPOI) began to trace out the companion’s orbit, and what began as routine observations turned into a rare eclipse prediction: the distant companion was set to cross in front of the other two stars in February 2013, and then again in January 2015.
- See more at: http://www.skyandtelescope.com/astronomy-news/astronomers-observe-rare-stellar-eclipse-0602201503/