Barred spiral galaxy M109 (NGC 3992)

The bright spiral galaxy Messier 109 (NGC 3992) in Ursa Major, shown from a yellow-light (V-band) CCD exposure with an RCA CCD at the 1.1-meter Hall telescope of Lowell Observatory. North is at the top and east to the left, for direct comparison with a chart or eyepiece view. This display uses a logarithmic intensity transformation to preserve information across a wide dynamic range. The field is 3.6 by 6.0 arcminutes, which doesn't cover the whole galaxy (the bigger TI CCDs had gone to Australia at the time, to support observations of the Shoemaker-Levy 9 impact). The image was obtained in April 1994 by Bill Keel and Anatoly Zasov.

This galaxy shows an intriguing wealth of structure, including a central bar, almost complete surrounding ring, and outer arms which launch outward from dust lanes spiralling through the ring. Visually, this is one of the easier galaxies of its magnitude to find, lying 1.2 degrees southeast of Gamma Ursae Majoris in the bowl of the Big Dipper.

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Last changes: 5/2001      © 2001