How effective is a nuke, I see it in wiki dawn but i think it's way outdated..

Basically what happens when a nuke hits a colony, all troops reduce to 1 hp? What about if you shoot a colony with an ion cannon?

Also what would happen if i nuked a relic like 5 times.. does it's troops hp recover?

a nuke will kill 10% of the units at then target and the units will have an hp of 1.
the ion cannon will affect 10 random units in the target and will have half the HP.
And when you hit the target with a nuke the troops in it will heal 1 hp per tik

Yes, this basically sums it up. Although sending a nuke out takes up 25 energy (Which for me is alot), I only use nukes to really defend my alliance. I also build them to make other alliances anxious ( make them not want to come near me). I think the Ion cannon is very effective if you are in a war and your on defense.

to add somethg also is that if ur being attacked by squads and u use ion cannon then one of the squads get delayed 1 tik