When is the best time to observe Dheneb?

Dheneb is best observed from September through November, with peak visibility during October when it transits around midnight in the Northern Hemisphere.

Where is Dheneb located in the sky?

Dheneb lies in the constellation Cetus at right ascension 01h 09m and declination -10° 11′.

What telescope do I need to see Dheneb?

At magnitude 3.5, Dheneb is visible to the naked eye from dark skies, easy in any binoculars.

Dheneb — Star in Cetus

HIP 5364; Eta Ceti; 31 Ceti

Magnitude 3.5^m Star Cetus (Cet) Visible

Star Map + List + Plan

About Dheneb

Description

Dheneb, Eta Ceti, is a K1 III orange giant about 124 light-years away. It shines at magnitude 3.45 and is a mature red-clump star with a mass of about 1.8 Suns and a radius of 14 Suns. It should not be confused with Deneb (Alpha Cygni), the great supergiant of Cygnus — the similar names come from a common Arabic root.

Observing Tips

Dheneb marks the southern tail region of Cetus the Whale. Binoculars clearly show its warm yellow-orange color. It is well south on the celestial sphere and best observed from mid-northern to southern latitudes during the autumn months.

History

The name Dheneb comes from the Arabic "dhanab," meaning "tail" — the same root as Deneb (Cygnus's tail star) and Denebola (Leo's tail star). The IAU adopted the Cetus-specific spelling "Dheneb" in 2017 to distinguish it from Cygnus's Deneb.

Fun Facts

The confusing modern multiplicity of "tail" stars — Deneb, Dheneb, Denebola, Denebakrab, Deneb Algedi — all stem from the single Arabic word dhanab, applied separately to each constellation's tail end. The different IAU-adopted spellings help keep them distinct in modern references.