Messier 84, also cataloged as NGC 4374, is a bright Seyfert galaxy that shines at an apparent magnitude of 10.49, making it an accessible target for astrophotographers working with modest to mid-sized telescopes. Its relatively compact angular size of 6.5′ × 5.8′ means longer focal lengths help resolve its smooth elliptical glow and bright core against the surrounding field. With a surface brightness of around 23.0 mag/arcsec², capturing its outer halo rewards patient integration under dark skies and careful stretching in post-processing. Because it sits within a crowded region of the sky, wide framing can gather several neighboring galaxies in a single exposure, turning a single-target image into a rich galactic tableau.
Names and Catalog numbers
- M 84 (Messier 84)
- NGC 4374
- UGC 7494
- PGC 40455
Position and the cosmic neighborhood
Messier 84 (NGC 4374) lies in the constellation Virgo at a right ascension of 12h 25m 03.74s and a declination of +12° 53′ 13.1″. It resides in the heart of a densely populated stretch of sky, where numerous galaxies crowd together within a small field of view. This makes it an ideal anchor for astrophotographers building mosaics or wide-field frames, since a single well-composed shot can capture a chain of galaxies flanking Messier 84. Framing along this region rewards planning, as the alignment of nearby galaxies offers striking compositional opportunities.
Nice to Know
- Messier 84 is classified as a Seyfert galaxy, hinting at an active galactic nucleus that gives its bright core a distinctive punch in images.
- Spanning roughly 103,000 light-years across, it is comparable in physical extent to many large galaxies, yet appears compact at a distance of about 54.8 million light-years.
- Its measured radial velocity of 1014.57 km/s corresponds to a redshift of z = 0.00339, reflecting the cosmic expansion carrying it away from us.
- Carrying multiple designations including NGC 4374, PGC 40455 and UGC 7494, it is a well-documented favorite for deep-sky imagers exploring the Virgo region.
Brightness, distance and size
The object has an apparent magnitude of 10.5 mag, it lies about 54.8 million light-years from Earth and spans roughly 103,000 light-years across. On the sky it appears about 6.5′ × 5.8′ in size.
