Queen of the Dead part 2, 54
I don't know if you actually can see the island of Aegina (originally named Oenone according to some ancient sources) from the Acrocorinth, but let's just say that it's possible in this fantasy version of ancient Greece, because otherwise I don't know how Sisyphus could know where Zeus brought the girl.
so this got me wondering.. the Acrocorinth's summit is a bit over 1800 feet. according to this site, at 1000ft the horizon would be at a bit over 32 miles away, and at 2000ft it would be at a touch over 59 miles.
according to googlemaps's "measure distance" featue, the distance between the acrocorinth and Aegina is 32.14 miles. so the island is not below the horizon if veiwed from the top of the acrocorinth.
however there are two factors at play that would make it pretty hard to see.. first is that atmospheric scattering would blur a lot of detail more than 30 miles away. which for something as big as an island might not be much of a factor, assuming it is visible at all.
the big issue would be that a direct flight path over the acrocorinth to aegina passes over rugged hills that block most of the LOS to the island.