Delta Cephi - the Standard Candle

At the southeast corner of the house-shaped constellation Cepheus the King, there’s an intriguing variable star called Delta Cephei.
With clocklike precison, this rather faint star doubles in brightness, fades to a minimum and then doubles in brightness every 5.36 days.
You can see it change over a period of days. The entire cycle is visible to the eye alone in a dark-enough sky.
This star and others like it have secured a place as important standard candles for establishing the scale of the galaxy and universe.

Facts about Delta Cephei by Keith Turnecliff

This is a well known variable star, but also a striking double. As a double star for binoculars. Delta Cephei is a pretty, if somewhat challenging, sight.
It is a class of star that serves as an important 'standard candle' indicator of cosmic distances.
Following Delta Cephei's ups and downs can become addictive.

This star chart for represents the view from Long Itchington in mid October at 10pm.
Credits: Image courtesy of Starry Night Pro Plus 8, researched and implemented by Keith Turnecliff.