The PHB delineates the circumstances under which 2 spells could be cast in a turn.
My 15th-level Warlock knows Crown of Stars. The spell says it costs a bonus action to attack with a mote, which to my understanding leaves a full action to attack with the Eldritch Blast cantrip.
Is this right? It seems to check out, but it seems particularly devastating, especially if the target is hexed. This happened in an encounter recently and my Celestial warlock did monstrous amounts of damage.
Best Answer
You can attack with Crown of Stars and cast a spell with your action
Crown of Stars takes an action to cast, once cast it grant a bonus action ranged spell attack. This attack does not count as casting a spell so there is no limitation on what you can use your action for. The relevant part of Crown of Stars is below (emphasis mine):
The restriction you are concerned about is the bonus action spell casting rules:
Making a ranged spell attack (which Crown of Stars requires) does not count as casting a spell. Therefore this rule does not come into play. Even if it did you would still be allowed to cast Eldritch Blast as it is a 'cantrip with a casting time of 1 action'.