This is surely one of the
finest galaxies in the sky. It was missed by Messier due to
its southerly declination and awaited discovery by William
Herschel's sister Caroline while hunting comets.
Part of the Sculptor
group, NGC 253 lies only about four times as far as the M 31 spiral
in our local group. Often photographed by amateurs and professionals
alike, this galaxy reveals vast lanes of dust, which are clearly
visible in the HST image below as dark brown streaks. The dust in a
galaxy is often associated with the clouds of gas that stars form
out of. Its effect on our view is to block the light of stars behind
it and to scatter the blue starlight away, making the stars appear
more red than they really are. Notice the blue clumps. Those are
areas where stars have formed recently--the hottest stars are
generally brighter and appear blue. They are also the most massive.
The massive stars live very short lives compared to the others, so
when a cluster of stars has recently formed we see the light of the
many bright, blue stars. In time the blue stars will disappear. In
this way the blue regions in NGC 253 trace the places where stars
are actively being formed today.
NGC 253 is bright
enough to be visible in binoculars from a dark site, and even the
smallest of telescopes reveal a smaller version of M 31. In 8-inch
or larger scopes look for a mottling, particularly on the NW side.
Due to its southerly declination, NGC 253 does not rise high in the
sky for northern latitudes. For this reason it is best to observe it
from these latitudes as it crosses the meridian. In mid October NGC
253 crosses the local meridian at around midnight local time.
Eyepiece view in 6-inch at
50x. North is down and east is to the right.
Larger scopes (16-inch
or greater) will clearly reveal the many thin lanes of dust. Their
appearance around the nuclear bulge can leave the viewer with a
clear impression of the apparent tilt of the galaxy. NGC 253 seen in
one of these instruments is one of the most unforgettable sights in