This is a nice picture, and IC 342 is an interesting galaxy.
Thanks to the fact that IC 342 is very reddened, coupled with the fact that this image has been color-balanced in such a way that only the very bluest stars look blue, we can easily discern the different populations that make up this galaxy. Since IC 342 is a substantial galaxy, similar in size to the Milky Way, we most definitely expect it to have a yellow bulge - and it does.
Photo: ESO
Interestingly, we can see that the inner arms of IC 342 are yellower than the outer arms. The same phenomenon can be seen in spiral galaxy NGC 1232 at left. There is a substantial population of old stars in the inner arms of both IC 342 and NGC 1232.
NGC 1232 has a large number of sharply defined, thin arms. Only large galaxies tend to be so elegantly shaped. NGC 1232 therefore looks larger or at least brighter than IC 342, and it is, too. According to my software, NGC 1232 is twice as bright as IC 342.
NGC 6946 has more in common with IC 342 than NGC 1232 does. Like IC 342, NGC 6946 has rather broad arms. The arms are typically made of intermediate-aged stars of spectral classes A and F, and therefore they are muted in color rather than bright blue. Red emission nebulae stand out in both galaxies, and small blue patches of very hot blue stars can also be discerned. Interestingly, NGC 6946 is dust-reddened just like IC 342 and is seen through a veil of Milky Way dust, although the dust is thinner than the dust in front of IC 342. Very interestingly, NGC 6946 and IC 342 appear to be about equally bright, similar to the Milky Way.
But NGC 6946 clearly has more star formation than IC 342. There is so much star formation in NGC 6946 and so many supernovae that the entire galaxy is distorted. IC 342, by contrast, appears to be undisturbed by any internal turmoil.
In some ways, IC 342 is similar to M74. M74 is quite undisturbed, like IC 342. It is also similar in brightness to IC 342. But M74 is more elegantly shaped than IC 342, and it may or may not be intrinsically bluer.
Ann