M106
NGC 4258
Spiral
Properties
Position & Identifiers
Visibility
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About M106
Description
M106 is a large, bright spiral galaxy in Canes Venatici, about 23.5 million light-years from Earth. It has a spectacular system of anomalous spiral arms visible in radio and X-ray wavelengths, driven by jets from its active galactic nucleus. The galaxy spans about 135,000 light-years and harbors a 36-million-solar-mass supermassive black hole with a water maser — a natural microwave laser — in its accretion disk.
Observing Tips
Located about 5 degrees south of the Big Dipper's bowl, between Gamma and Beta Ursae Majoris extended toward Canes Venatici. In binoculars it appears as a large, elongated fuzzy patch. A 4-inch telescope shows a bright oval with a strong nuclear concentration. An 8-inch reveals hints of spiral arm structure under dark skies. One of the brighter non-Virgo galaxies. Best observed from March through July.
History
Discovered by Pierre Mechain in July 1781. Like M105, it was not in Messier's published catalog and was added later. The water megamaser in its nucleus was discovered in 1995 and has been used to make one of the most precise distance measurements to any galaxy.
Fun Facts
The water megamaser in M106's nucleus has enabled the most precise geometric distance measurement to any galaxy beyond the Local Group — 23.5 million light-years with an uncertainty of only 3%. This measurement, independent of the cosmic distance ladder, provides a crucial anchor for cosmological distance scales. M106 also has anomalous spiral arms visible only at radio and X-ray wavelengths, heated by jets from its active nucleus.
Community Photos (1)
Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), and R. Gendler (for the Hubble Heritage Team). Acknowledgment: J. GaBany. License: Public domain. (Wikimedia Commons)
Skybred Feb 28, 2026