Interesting to compare modern CCD technology to what was obtained from the Hubble telescope a decade or so ago. Top image is my shot, and bottom is the Hubble composite.
M51: Stack of 4 - 5 minute acquisitions from New Mexico.
This Hubble image is inverted from the original to compare with my New Mexico shot above. (Reference: H II Region Luminosity Function of the Interacting Galaxy M51. Astrophysics Journal, 2011. DOI: 10.1088/0004-637X/735/2/75)