ABOUT THIS IMAGE:

This spectacular image of the large spiral galaxy NGC 1232 was obtained on September 21, 1998, during a period of good observing conditions. It is based on three exposures in ultra-violet, blue and red light, respectively. The colors of the different regions are well visible : the central areas contain older stars of reddish color, while the spiral arms are populated by young, blue stars and many star-forming regions. Note the distorted companion galaxy on the left side, shaped like the greek letter "theta".

NGC 1232 is located 20º south of the celestial equator, in the constellation Eridanus (The River). It was discovered on October 20, 1784 by William Herschel. The distance is about 60 million light-years, but the excellent optical quality of the VLT and FORS allows us to see an incredible wealth of details. At the indicated distance, the edge of the field shown corresponds to about 200,000 light-years, or about twice the size of the Milky Way galaxy.

The image is a composite of three images taken behind three different filters: U (360 nm; 10 min), B (420 nm; 6 min) and R (600 nm; 2:30 min) during a period of 0.7 arcsec seeing. The field shown measures 6.8 x 6.8 arcmin. North is up; East is to the left.

From Wikipedia:

NGC 1232 is an intermediate spiral galaxy about 60 million light-years away in the constellation Eridanus.

It is dominated by millions of bright stars and dark dust, in spiral arms rotating about the center. Open clusters containing bright blue stars are sprinkled along these spiral arms, with dark lanes of dense interstellar dust between. Less visible are dim normal stars and interstellar gas, producing such high mass that they dominate the dynamics of the inner galaxy. Not visible is matter of unknown form called dark matter, needed to explain the motions of the visible material in the outer galaxy.

NGC 1232 and its satellite are part of the Eridanus cluster of galaxies, along with NGC 1300.