Look to luminous Messier 77 

Messier 77 is a large and luminous Seyfert-II active galaxy that produces great images and can be found and observed through a small- to medium-aperture telescope. Image: Adam Block.

Messier 77 (NGC 1068 and Arp 37) is an impressive spiral galaxy in Cetus that presents face-on to our Earthly perspective. Other than Local Group heavyweights Messier 31 and Messier 33, perhaps only Messier 74 in Pisces can claim bragging rights over it. 

Messier 77 is classed as a type-II Seyfert galaxy, a class of active galaxies bright at infrared wavelengths and powered by intense radiation blasted out from an accretion disc around a  supermassive black hole at their heart. Though Seyfert galaxies are less energetic than quasars, Messier 77 is actually very luminous across the electromagnetic spectrum. It’s also one of the closest active galaxies, lying around 45 million light years away.

Messier 77 shines with an integrated magnitude of +8.8 and can be located through a large finderscope or a pair of binoculars. It gives up its secrets only grudgingly to visual observers, but imagers will be delighted with what Messier 77’s data yields. 

Messier 77 lies in the far north-eastern regions of Cetus, just south of the head of the sea monster, the constellation’s distinctive hexagonal-shaped asterism. AN graphic by Greg Smye-Rumsby.

How to observe

Messier 77 is located in the north-eastern quadrant of the largely southern constellation of Cetus, the Sea Monster, whose northern extremities are quite well-placed from UK shores. 

Cetus’ main hexagonal-shaped asterism (which forms the head of the monster) is found in the constellation’s far north-east quadrant and consists of third- to fourth-magnitude stars, including magnitude +2.5 Menkar (alpha [α] Ceti] and magnitude +3.5 Kaffaljidhma (gamma [γ] Ceti). Messier 77 is easily located just over three degree south of Kaffaljidhma. At mid-November, Messier 77 culminates at about 11pm and achieves an altitude of nearly 40 degrees from London. 

A small telescope reveals Messier 77 as a very small though high-surface-brightness spot of light. Amateur images show the galaxy extends to 6.9’ x 5.9’ and appears like a ‘galaxy within a galaxy’, with its three-arcminute-wide oval centre showing intense spiral structure surrounded by much fainter, sweeping spiral arm. 

Visual observers will struggle to see anything other than the bright central region unless observing through a telescope of at least 300–350mm (12 to 14 inches) in aperture. 

Messier 77 also gives its name to a small group of galaxies, which include, among others, nearby NGC 1055 (see the Deep-Sky tour in Astronomy Now October 2021), NGC 1073, UGC 2161, UGC 2275 and UGC 2302.