The Caldwell Objects

17 & 18
clude, "it could be the case that the youngest stars
originate from material ejected from dying stars
and that this process would only be efficient
enough in the center of the galaxy."
Interestingly, NGC 147 does not seem to
have shared in this recent star-forming epoch.
Hubble Space Telescope data have shown that
star formation ceased there about 1 billion years
ago. No evidence for star-forming regions could
be found, nor any evidence for star-forming dust.
The galaxy's youngest stars are concentrated
toward the center, as is the case in NGC 185.
78
After scrutinizing these galaxies at the highest
workable magnification, return to low power and
try glimpsing both of them again in the same
field of view. Seen this way, NGC 147 and NGC
185 remind me of M31's two brightest
companions (M32 and M110) minus the great
spiral itself. I can easily imagine NGC 185 taking
the place of the round elliptical galaxy M32 and
the more elongated NGC 147 representing M110.
Try comparing all these systems on the same
night to gain an appreciation for this remarkable
collection of dwarf galaxies.
Deep-Sky Companions: The Caldwell Objects