The sky around Cetus A at true scale, north up and east left, with stars to magnitude 8. The circles show the field of a low-power eyepiece and of 10×50 binoculars.
Cetus A is a spiral galaxy in Cetus, 46 million light-years away
Cetus A (M77, NGC 1068, Arp 37, PGC 010266, UGC 02188) is a spiral galaxy in the constellation Cetus, 46 million light-years away. It shines at magnitude 9.3 and spans 7′ × 6′ of sky, about 92,900 light-years across. It is best in a small telescope, 4 to 6 inches, and it is highest in the evening sky in December.
Galaxy: a system of billions of stars, gas and dust held together by gravity, far outside the Milky Way. Spiral galaxies have a disk with arms; elliptical galaxies are smooth, round or oval swarms of older stars.
Cetus A is Arp 37, one of Arp's spiral galaxies with low surface brightness companions
Halton Arp photographed it for his Atlas of Peculiar Galaxies (1966) as field Arp 37. It is in his group of spiral galaxies, Arp 1 to 101, under the category Spiral galaxies with low surface brightness companions.
Cetus A lies 3.3° south of Kaffaljidhma, the magnitude 3.5 star. Three fingers held at arm's length cover about 5°.
Cetus A is highest in the evening in December
The chart gives its height above the horizon at 9 pm through the year, from 60°N to 40°S. It can be seen from the whole southern hemisphere and north to about 90°N.
Cetus A is 46 million light-years away
The light seen from Cetus A tonight left it about 46 million years ago, long before modern humans existed. It ranks 92 of 109 by distance among the 110 Messier objects. Distance source: flow model (NAM), Anand 2021.
