This is a picture I took of M33. It’s not much, but revealing all the same, given the fact that it’s a simple picture taken in primary focus with a standard DSLR. 25″ exposure time, a special high ISO setting (over ISO 3200) and a C8; magnification about 40 times.
M33 is the well known “pinwheel” galaxy. The picture shows an area that is magnified about 40 times, more or less (f=2032 mm, 2032mm/50mm -standard- = about 40). It’s about three quarter of an arc minute of sky.
You can see the center of M33. But it’s only the center. M33 is larger than this picture shows. Look at the annotated picture below, which indicates a few stars from our own galaxy and a few NGC numbers.These are all star forming regions in the M33, and not at the edge.
The 8th magnitude HD9483 star is about halfway from the center to the edge of M33, the same goes for NGC604 below left. The M33 is tilted; the long axis runs from above left to below right. The edges are, as stated, outside the picture.
The stars near to the center of M33 are all in our galaxies. One of the fainter ones is indicated as a magnitude 14.2 star, giving you an indication what you can do with 25 seconds on a standard camera and a 203mm mirror scope.
Puzzling to find out what you see on a picture can be as much fun as observing itself.