Idaho Skies Transcript for April 19th, 20th, and 21st

PAUL
Welcome to Idaho Skies for April 19th, 20th, and 21st. We’re your hosts, Paul...

RACHEL
...and Rachel.

PAUL
Ancient cultures understood that some stars varied in brightness, but it wasn’t until 1783 that an astronomer proposed a mechanism to account for stellar variability.

RACHEL
The astronomer’s name was John Goodricke, and he was born in the Netherlands on September 17th, 1764. A childhood illness left him profoundly deaf, but he didn’t let this prevent him from carrying out astronomical research. Upon his return to England, he took up observing variable stars on the advice of a neighbor.   

PAUL
One of the most famous variable stars is named Algol. In Arabic, its name means the ghoul and people normally refer to it as the demon star. Until Goodricke, no one appears to realize that Algol changed brightness at a regular period. Goodricke’s observations indicated the star maintained constant brightness for 2.9 days.

RACHEL
Then for about 10 hours, Algol becomes about half as bright. Since this period was so regular, Goodricke proposed that Algol consisted of two stars. Goodricke thought the stars orbited each other, and when the fainter star passed in front of the brighter, it caused an eclipse. Astronomers today can detect an even smaller eclipse that occurs when the brighter star eclipses the fainter one.     

PAUL
This variability of Algol is very noticeable to stargazers, even to those living in Boise. To see it yourself, use a star map to show you where to find the constellation of Perseus and its star Algol. Currently, Algol appears in the low northwest after dark. Check out online resources for the times and days that Algol reaches minimum brightness.   

RACHEL
That’s Idaho Skies for the 19th, 20th, and 21st of April.

PAUL
Be sure to follow us on Twitter @IdahoSkies for this week’s event reminders and sky maps.
For Idaho Skies this is Paul...

RACHEL
...and Rachel.

RACHEL
Dark skies and bright stars.