During the fight, the boss will place a Time Bomb on random players, which will eventually detonate and cause raid-wide damage. If the detonation goes off while the player is standing on top of one of the purple/blue circles surrounding the Nightwell, a beam of light will begin to emerge from the circle, which acts as a 'spotlight'.
To obtain the achievement, simply activate each of the 8 circles around the room using Time Bomb, and then defeat the Chronomatic Anomaly. Note that the number of Time Bombs that occur varies depending on the difficulty setting, making it harder on Normal, for example, to achieve the required number than it would be on Heroic difficulty.
Patches and hotfixes
- Hotfix (2017-05-22): "Grand Opening now requires 8 spotlights activated during the Chronomatic Anomaly encounter (was 12)."
- Patch 7.0.3 (2016-07-19): Added.