M81 · Bode's Galaxy

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Credit NASA, ESA and the Hubble Heritage Team (STScI/AURA) · Public domain

Chinese name	波德星系
Type	Galaxy
Constellation	UMa
RA	09h56m
Dec	+69°
Apparent magnitude	6.9ᵐ
Hemisphere	Northern
Best season	Spring
Difficulty	Moderate
Focal length	中焦 600–1000mm

About

Bode's Galaxy lies about 11.7 million light-years away in Ursa Major and is the dominant member of the M81 Group, named after the German astronomer Johann Bode. It boasts symmetric, well-ordered grand-design arms and a bright yellow bulge, with a supermassive black hole of roughly 70 million solar masses at its core, making it a textbook large spiral. It sits barely half a degree from the violent starburst galaxy M82 (the Cigar Galaxy), whose gravitational interaction with M81 triggered that starburst, and the two can be imaged in a single frame. Deep wide-field exposures also capture the faint integrated flux nebula (IFN), galactic dust drifting around both. With clear structure and a bright core, it is a popular medium-focal-length galaxy target.