The sky around Arp 273 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.
Arp 273 is a galaxy pair (Sb:) in Andromeda, 337 million light-years away
Arp 273 (UGC 1810, UGC 1813) is a galaxy pair (Sb:) in the constellation Andromeda, 337 million light-years away. It shines at magnitude 12.9 and spans 1.6′ × 1.2′ of sky, about 156,800 light-years across. It is a telescope object, 6 inches or larger, 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.
Arp 273 is one of Arp's double galaxies with connected arms
Halton Arp photographed it for his Atlas of Peculiar Galaxies (1966) as field Arp 273. It is in his group of double and multiple, Arp 269 to 332, under the category Double galaxies with connected arms. The field holds 2 galaxies.
Arp 273 lies 4.4° southeast of Almach, the magnitude 2.1 star. Three fingers held at arm's length cover about 5°.
Arp 273 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 northern hemisphere and south to about 51°S, and never sets north of 51°N.
Arp 273 is 337 million light-years away
The light seen from Arp 273 tonight left it about 337 million years ago, long before modern humans existed. It ranks 363 of 422 by distance among the galaxies on Go Astronomy. Distance source: Cosmicflows-4 (Tully et al. 2023), Tully-Fisher.
