The Ursa Minor Dwarf Galaxy is a diffuse, low-surface-brightness dwarf galaxy that presents one of the more challenging targets in the deep-sky imaging repertoire. With an apparent magnitude of 10.6 mag spread across an angular size of 0.5° (32′), its light is smeared so thinly that its surface brightness sits at a very demanding 26.77 mag/arcsec², making it nearly invisible in single short exposures. Capturing it well rewards long total integration times under genuinely dark skies, where its sparse scattering of stars gradually emerges above the background noise. Wide-field setups suit it best, since the galaxy fills a substantial patch of sky yet never delivers a bright, concentrated core to lock onto.
Names and Catalog numbers
- Ursa Minor Dwarf Galaxy
- UGC 9749
- PGC 54074
Position and the cosmic neighborhood
The Ursa Minor Dwarf Galaxy sits high in the northern sky within the constellation Ursa Minor, at a right ascension of 15h 09m 08.0s and a declination of +67° 13′ 21″. Its far-northern placement is a real advantage for imagers at mid-northern latitudes, where it remains circumpolar and available across much of the night rather than skimming the horizon. As one of the small satellite companions orbiting our own Milky Way, this galaxy shares its neighborhood with the extended halo of the Galaxy, and its faint stellar field is often framed against the sparse foreground of the little bear. Also cataloged as PGC 54074 and UGC 9749, it is a rewarding project for observers seeking something well off the beaten path.
Nice to Know
- At a distance of about 326,000 light-years, the Ursa Minor Dwarf Galaxy is a close satellite companion of our own Milky Way.
- Despite spanning a physical diameter of roughly 3,060 light-years, its light is so diffuse that it ranks among the most difficult deep-sky objects to photograph well.
- Its surface brightness of 26.77 mag/arcsec² means the galaxy is far fainter per unit area than the night sky itself in many locations, demanding exceptionally dark conditions.
- Its blueshifted radial velocity of -246.9 km/s (redshift z = -0.000823231) shows it is moving toward us, a hallmark of a nearby galaxy bound to the Milky Way.
Brightness, distance and size
The object has an apparent magnitude of 10.6 mag, it lies about 326,000 light-years from Earth and spans roughly 3,060 light-years across. On the sky it appears about 0.5° (32′) in size.
