Steven Juchnowski (sjastro) posted this image of D 507 = NGC 55
http://users.westconnect.com.au/~sjastro/ngc55c.html
NGC 55 is visible in a 50mm finder.
Dunlop discovered "A beautiful long nebula, about 25' in length; position north preceding, and south following, a little brighter
towards the middle, but extremely faint and diluted to the extremities. I see several minute points or stars in it, as it were through the nebula: the nebulous matter of the south extremity is extremely rare, and of a delicate bluish hue. This is a beautiful object."
He saw it 182 years ago on Fri 7/7/1826 at 5:05am with his 9" reflector. He also discovered NGCs 134, 7552 and 7582 that night.
Imagine discovering 4 galaxies in one night!