Celestial Beacon

This is an entry in the Type column of the Overview Panel.
Its icon in the IC column is the beacon designation (an upside down triangle with a tail on top), colored white.
To make these appear in your Overview Panel, go to the Overview settings-->Filters tab-->Types subtab-->Celestial section. Place an X in the checkbox entitled Beacon. These sites can contain a cosmos combat site, or an acceration gate to a cosmos deadspace, or simply a point of interest. They will have a specific name in the Name column of the Overview Panel. The Nefantar Ruins in the Barkrik system is an example of a combat-type cosmos Celestial Beacon site.