When deleting surface in SE, or generating one by a a ship anchoring, Ion cannon crashes the server with an error about indexing a surface.

The mod Auto-Targeting Ion Cannon (SE Edition) (0.1.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event auto-targeting-ion-cannon::on_nth_tick(60)
auto-targeting-ion-cannon/control.lua:7: attempt to index local 'surface' (a nil value)
stack traceback:
auto-targeting-ion-cannon/control.lua:7: in function 'find_target'
auto-targeting-ion-cannon/control.lua:21: in function 'shoot'
auto-targeting-ion-cannon/control.lua:30: in function 'shoot_many'
auto-targeting-ion-cannon/control.lua:36: in function 'do_tick'
auto-targeting-ion-cannon/control.lua:42: in function <auto-targeting-ion-cannon/control.lua:40>

How do you annihilate whole planets. are you a planet killer? ;-)
I'll take a look at that. shouldn't be a big deal, but I still have to find the time to do it.