Dense cluster of about 80-100 galaxies

It’s probably already

Uhhh. But that is really very, very many galaxies.

Abell 1656, aka the Coma Cluster

How are you able to identify that? Are you using one of the overlays?

Are they actually close to each other?

…wait, I’m doing my internet reading on The Coma Cluster…

In this case I activated “NGC/IC galaxies” and clicked on the link to NGC 4889 and there was a note:
" brightest cluster galaxy in ACO 1656 (2004ApJ…617…879L)"

Just check the position of the Coma Cluster in SIMBAD:
ACO 1656 – Cluster of Galaxies
194.9529 +27.9806