It does 150 damage per volley, one volley per 1.25 seconds, at a total of 20 volleys, which takes 25 seconds to go off.
It does this damage to all enemy forces within the range of the ability (10,000km).
Shield mitigation does reduce it.
A frigate or cruiser will have its shield mitigation maxed after approximately the 6th volley-a capital ship after approximately the 7th. Due to armor increases from tech, differing armor among ships, and capital ships leveling up, you may need to add an additional volley for frigates/cruisers and up to two additional volleys for capital ships to get the numbers to match up.
[Knowledge acquired.]