…continuedExploring the Hubble Sequence by Eye
On the second Palomar Observatory Sky Survey (POSS-II), M84 looks like a pure elliptical galaxy without a hint of a disk. This agrees with the online NASA Extragalactic Database, which lists M84's type as E1. Various observations I have made over the years with different telescopes indicate the brightness rising smoothly and quickly toward the center, where a conspicuous but nonstellar nucleus resides. The outer boundary seems to be indefinite because it merges so smoothly with the sky background. On the POSS-II film (digitized portions of which are available here), M86 shows a weak but distinct collar of brightness in the inner regions and a huge oval corona in the outermost parts larger even than that of M87, which some consider to be the dominant member of the Virgo Cluster. These two features signify the type S0-, the “earliest” lenticular following the pure ellipticals. NED also considers the galaxy to be a transition case.
Telescopically M84 and M86 appear outwardly similar, but they differ subtly in their inner regions. While M84 fades without a break until lost to the sky's background glow, M86 has a zone where the brightness nearly levels off for an arcminute or two in radius. This indicates one can discern the disklike attributes of lenticular galaxies even in a small telescope. Both galaxies have nuclei that rise sharply from the bright background of their inner regions. If you observe them at quite high magnification, say 200x on an 8-inch telescope, can you tell any difference between them?