NGC 309 - SAB(r)c

NGC 309

De Vaucouleurs Atlas Type: SAB(r)c

Filter: g

Telescope: SDSS 2.5-m
North right , East up
Field Dimensions: 2.7 x 2.0 arcminutes

RC3 Type: SAB(r)c
RSA Type: Sc(r)I
Surface Brightness Range Displayed: 19.0-24.5 mag per square arcsec
Absolute Blue Magnitude: -22.2
Elmegreen Spiral Arm Class: AC 9

De Vaucouleurs Atlas Description:

The face-on orientation of this excellent late-type spiral reveals two interesting features. First, the inner ring is a highly elongated feature in the plane of the galaxy. Although the ring appears to be made of wrapped spiral arms, it is sufficiently closed to merit the (r) classification. Secondly, the weak bar crossing the ring is clearly misaligned with its intrinsic major axis. This places NGC 309 into the rare class of misaligned bar-ring galaxies , of which ESO 565-11 (book Section 2.13) is the type example. Irrespective of these facts, NGC 309 is a very good example of an Sc galaxy with an inner ring .