Deneb Kaitos (Beta Ceti, sometimes also called Beta Ceti and Diphda ranks as the most brilliant star in the constellation Cetus the Whale (or Sea-Monster). This star shines on par with Polaris the North Star. There is a famous variable star also in Cetus, called Mira. And Mira might sometimes brighten up enough to match Deneb Kaitos, though only extremely rarely. Mira typically remains much too faint to see with the unaided eye. Meanwhile, as seen from mid-latitudes in the Northern Hemisphere, Deneb Kaitos soars highest in the southern sky when the Big Dipper falls lowest in the northern sky, or goes beneath your northern horizon. In other words, you’ll find Deneb Kaitos shining highest at about 9-10 p.m. local time, from now until about mid-November.
The stars return to the same place in the sky about 2 hours earlier with each passing month (or four minutes earlier with each passing day). In middle January, look for Deneb Kaitos to reach its high point around 7 p.m. local time. On February evenings, this star drifts into the southwest sky, and disappears from the evening sky by March.
It’s easy to locate Deneb Kaitos if you’re familiar with the Great Square of Pegasus. Locate the star by drawing an imaginary line through the two Great Square stars Alpheratz and Algenib.
At nearly 100 light-years distant, Deneb Kaitos is a giant of a star, sporting a diameter 17 times larger than our sun’s. Check out this star with binoculars sometime and note its orange complexion. The orange color indicates a rather low surface temperature, and also lets us know that this star is entering into the autumn of its years.
Bottom line: Deneb Kaitos, or Beta Ceti, is the brightest star in the constellation Cetus the Whale.