Equinox | Magic: The Gathering
Formats Equinox is Legal in
Official Oracle Text for Equinox
Enchanted land has ": Counter target spell if it would destroy a land you control."
Official Rulings for Equinox
10/4/2004 : Equinox will not counter a spell that has a random chance of destroying a land.
10/4/2004 : Equinox will not counter a spell which would indirectly cause destruction of one of your lands.
10/4/2004 : The ability can target any spell, even one that would not destroy a land.
10/4/2004 : Equinox will not counter a spell that deals damage to an animated land, even if it would deal more damage than the land's toughness. This is because the spell itself does not destroy the land directly. The land is destroyed by a game rule.
10/1/2008 : Will not counter a spell which would destroy a land only if a choice is made.
9/20/2013 : When the activated ability resolves, determine whether the targeted spell would destroy a land if it resolved right then. If it would, then counter that spell. Otherwise, it is not countered, even if the spell could, under other circumstances, destroy a land.