Binoculars?

[Tapok]

Hey guys,

What is the role of the binoculars within this game? It's something I've never figured out, and I've been playing since Soldiers.

I understand that in multiplayer it reveals part of the map, but what about in singleplayer in which you can see the enemy at all times anyway? I'm playing the mission where you have to capture the lighthouse (Second campaign) and one character says he can call in artillery from the nearby battleship - I assume you use the binoculars for this, but I can't get that to work. What do I need to do?

Oh, also: What does "Call for Ally" (F9) do? Never been able to figure that one either.