Cetus

Cetus is the fourth largest constellation, visible in the months around September just to the south of the ecliptic.

The ecliptic passes less than 0.25° from one of its corners. Thus the moon and planets will enter Cetus briefly and the southern part of the sun appears in Cetus for about one day each year.

As seen from Mars, the ecliptic (apparent plane of the sun and also the average plane of the planets which is almost the same) passes into Cetus – the centre of the sun is a foreground object in Cetus for around six days shortly after the northern summer solstice.

Despite its size, Cetus has few bright stars, and because it lies far from the plane of the Milky Way, it also has few deep sky objects. However, it does contain a number of galaxies, including the Messier object M77, a bright spiral galaxy viewed in a face-on orientation.

The star Mira, also known as o-Cet, was the first variable star to be discovered, by David Fabricius in 1596. Its brightness fluctuates between mag 3 and 10 with a 332-day period. Today it is the prototypical example of the Mira class of variable stars.

Cetus is often identified as a whale, or perhaps as the sea monster sent by Poseidon to ravage the kingdom of Cepheus and to which Andromeda was to be sacrificed. The monster was slain by Perseus

The area of the sky around Cetus is often known as The Sea or the Water, because it contains a number of water-related constellations including Aquarius, Eridanus and Pisces.

In the Indian system Cetus is called ತಿಮಿಂಗಿಲ (Timingila) which translates to Whale.

Cetus contains:

• Stars
  • Diphda (mag 2.0)
  • Menkar (mag 2.5)
  • η-Cet (mag 3.4)
  • τ-Cet (mag 3.5)
  • ι-Cet (mag 3.5)
  • γ-Cet (mag 3.6)
  • θ-Cet (mag 3.6)
  • Baten Kaitos (mag 3.7)
  • υ-Cet (mag 4.0)
  • δ-Cet (mag 4.1)
  • π-Cet (mag 4.2)
  • ξ²-Cet (mag 4.3)
  • μ-Cet (mag 4.3)
  • ξ¹-Cet (mag 4.4)
  • AE Cet (mag 4.5)
  • 2-Cet (mag 4.5)
  • χ-Cet (mag 4.7)
  • λ-Cet (mag 4.7)
  • σ-Cet (mag 4.7)
  • 20-Cet (mag 4.8)
  • φ¹-Cet (mag 4.8)
  • ε-Cet (mag 4.8)
  • κ-Cet (mag 4.9)
  • ρ-Cet (mag 4.9)
  • ν-Cet (mag 4.9)
• Open Clusters
  None
• Globular Clusters
  None
• Galaxy
  • Messier 77 (mag 8.9)
  • NGC 247 (mag 8.9)
  • IC 1613 (mag 9.0)
  • IC 127 (mag 9.2)
  • NGC 936 (mag 10.1)
  • NGC 908 (mag 10.2)
  • NGC 720 (mag 10.2)
  • NGC 1052 (mag 10.5)
  • NGC 584 (mag 10.5)
  • NGC 1055 (mag 10.6)
  • NGC 45 (mag 10.7)
  • NGC 210 (mag 10.9)
  • NGC 596 (mag 10.9)
  • NGC 578 (mag 10.9)
  • NGC 864 (mag 11.0)
  • NGC 1087 (mag 11.0)
  • NGC 779 (mag 11.0)
  • NGC 943 (mag 11.0)
  • NGC 1073 (mag 11.0)
  • NGC 942 (mag 11.0)
  • NGC 1042 (mag 11.0)
  • NGC 636 (mag 11.3)
  • NGC 1022 (mag 11.3)
  • NGC 428 (mag 11.4)
  • NGC 192 (mag 11.4)