As long as by ultra rare, you mean for both the player and the enemies. Rare enough that encountering multiple celestial death rays in one fight would be very bad luck. As it is now, if you get a celestial sector 3, it seems that maybe half the ships have celestial death rays. In my example, 7 out of 9 ships that spawned at the station had one.
As for the nukes, I think having extra missiles as interference doesn't help sometimes because often the nuke is not shot down by point defenses or drones. Often the nuke collides with a projectile from the enemy's main guns.
I actually love using setups that spam a lot of projectiles (lots of ion cannons, projectile cannons, flak, dual plasma, all with burst upgrade) because it's so efficient at blocking missiles, nukes, and swarms of drones.
