Another amazing modern observer is Kent Wallace from California.
He attempted to observe 1064 planetary nebulae.
692 were seen.
359 eluded him.
13 were uncertain but may have been seen.
The northern PN were observed from California and the southern PN from Western Australia. He uses a 20" Dob without any goto aids.
His list is at:
www.blackskies.org/PN_Files/SECGPN_V6DS.xls