I should have replied to this image yesterday, but better late than never. Thanks, Juan Lozano de Haro, what an interesting picture! I wasn't aware that there is a galaxy cluster located apparently right next to NGC 891, although in reality NGC 891 and Abell 347 are of course separated by vast distances in space.
To the lower right of the bright yellow star is an edge-on galaxy, NGC 898, that looks very much like NGC 891, except that it hasn't got a visible dust lane. I guess the apparent size of NGC 898 is really just one eighth of the apparent size of NGC 891, and NGC 898 may well be eight times farther away. Interesting!
NGC 891. Photo: Bob Franke.
You will forgive me now for talking about NGC 891, because it is really such an interesting galaxy. It is definitely one of the most perfectly edge-on galaxies I know. The bright nucleus is completely hidden by the central dust lane, and it is almost impossible to say which half of the bulge, the upper half or the lower half, sticks out more from the dust lane.
Note, too that NGC 891 has a very extensive yellow disk. At least half of its disk appears to be yellowish, and only the relatively faint outer half of it is bluish, apparently from intermediate-aged stars of spectral classes A and F.
NGC 4565. Photo: Johannes Schedler.
It is interesting to compare NGC 891 with similarly edge-on (but not as perfectly
edge-on) NGC 4565. Note that NGC 4565 has a more extended disk than NGC 891 and is larger in overall size. Note that it has a larger component of A- and F-type stars in its disk, since its disk is bluer than the disk of NGC 891. But note, too, that its dust lane is a lot more "quiet" than the dust lane of NGC 981.
The dust lane of NGC 891 is a busy place. Note the obvious blue star clusters on the left side of the central dust lane in Bob Franke's picture. As for NGC 4565, it is not certain that the overall mottling of the dust lane represents anything else than different levels of extinction by dust.
Also note the large number of smoking "chimneys" in the dust lane of NGC 891. Many supernovas have popped off here. The dust lane of NGC 4565 is much less disturbed and displays a much smaller number of obvious chimneys.
In a way, NGC 891 is like a small fast car
outrunning its slow, steady competitor.