Messier Index/M77

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Cetus A
Spiral Galaxy M77
Observation data (w:J2000 epoch)
Constellation w:Cetus
Right ascension 2h 42m 40.7s[1]
Declination -00° 00′ 48″[1]
Redshift 1137 ± 3 km/s[1]
Distance 47.0 Mly (14.4 Mpc)[2]
Type (R)SA(rs)b[1]
Apparent dimensions (V) 7′.1 × 6′.0[1]
Apparent magnitude (V) 9.6[1]
Notable features One of the biggest galaxies
of w:Messier's catalog.
Inclination estimated to be 40°.[3]
Other designations
Cetus A, M77, NGC 1068, UGC 2188, PGC 10266, Arp 37[1]

Messier 77 (also known as NGC 1068) is a barred spiral galaxy about 47 million w:light-years away in the w:constellation w:Cetus. Messier 77 is an w:active galaxy with an w:Active Galactic Nucleus (AGN), which is obscured from view by astronomical dust at visible wavelengths. The diameter of the molecular disk and hot plasma associated with the obscuring material was first measured at radio wavelengths by the w:VLBA and w:VLA. The hot dust around the nucleus was subsequently measured in the mid-infrared by the MIDI instrument at the w:VLTI. It is the brightest[4] w:Seyfert galaxy and is of type 2.[2]

M77, amateur image. Courtesy of Hunter Wilson

Messier 77's diameter is a 170,000 light-years.


Messier 77 was discovered by w:Pierre Méchain in w:1780, who originally described it as a nebula. Méchain then communicated his discovery to w:Charles Messier, who subsequently listed the object in his catalog.[5] Both Messier and w:William Herschel described this galaxy as a star cluster.[5] Today, however, the object is known to be a galaxy.

External links