Messier 66, also cataloged as NGC 3627, is a bright barred spiral galaxy that presents itself as a rewarding target for deep-sky imagers thanks to its integrated magnitude of 8.92 mag. With an angular size of 11′ × 6.0′, it fits comfortably within the field of view of most telescope and camera combinations while still offering enough detail to reveal its asymmetric spiral arms and dusty texture. Its moderate surface brightness of 22.138 mag/arcsec² means that longer integration times and dark skies help draw out the fainter outer structure and the subtle knots of star-forming regions. Positioned in Leo, this galaxy is a classic springtime subject and a frequent companion in wide-field mosaics of the surrounding galaxy group.
Names and Catalog numbers
- M 66 (Messier 66)
- NGC 3627
- UGC 6346
- PGC 34695
- Arp 16
Position and the cosmic neighborhood
Messier 66 (NGC 3627) sits in the constellation Leo at a right ascension of 11h 20m 15.02s and a declination of +12° 59′ 29.4″, placing it well within reach of northern-hemisphere astrophotographers. It is one of the members of the well-known Leo Triplet, and its proximity to bright neighboring galaxies makes it an ideal anchor for wide-field compositions that capture several galaxies in a single frame. The galaxy’s slightly distorted spiral form, likely shaped by gravitational interactions with its companions, gives imagers plenty of structure to resolve when framing the region.
Nice to Know
- Messier 66 carries the peculiar-galaxy designation Arp 16, reflecting its visibly distorted and asymmetric spiral arms.
- It is one of the prominent members of the Leo Triplet, making it a favorite for multi-galaxy wide-field astrophotography.
- Its physical diameter spans roughly 79,600 light-years, a scale comparable to many large spiral galaxies.
- At a distance of about 23.9 million light-years, it recedes with a radial velocity of 724 km/s, corresponding to a redshift of z = 0.00241793.
Brightness, distance and size
The object has an apparent magnitude of 8.9 mag, it lies about 23.9 million light-years from Earth and spans roughly 79,600 light-years across. On the sky it appears about 11′ × 6.0′ in size.
