WotLK Classic How to Unlock Algalon the Observer Boss Fight

Algalon the Observer is a challenging, Hard Mode-only boss found in Ulduar, and needs a key to access the Celestial Planetarium where he is located. To unlock the door, at least one player from the raid group must possess the key – rogues cannot pick the lock. Completing four quests with Hodir, Thorim, Freya, and Mimiron requires the acquisition of Sigils, and the only way to get them is to successfully complete Hard Mode battles.

Celestial Planetarium Key

For both 10-person and 25-person Ulduar, there are two different versions of this key:

• Celestial Planetarium Key (10-person Raid)
• Heroic Celestial Planetarium Key (25-person Raid)

Note, that each key has its own quests line and despite being similar are needed to be done in corresponding Raid Difficulty (10 or 25 person).

Unlocking the Celestial Planetarium

In order to get Celestial Planetarium Key or Heroic Celestial Planetarium Key, player needs to complete this steps:

• Complete I Choose You, Steelbreaker (Defeat the Assembly of Iron with Steelbreaker as the last member alive) or I Choose You, Runemaster Molgeim (Defeat the Assembly of Iron with Runemaster Molgeim as the last member alive), enabling Archivum Data Disc to drop (not personal loot, so raid will need to decide who gets it).
• Accept the quest from the disc and bring it to the Archivum Console, located beyond the Assembly of Iron.

• After listening to the Archivum Console speak, accept the quest The Celestial Planetarium from Prospector Loren. Locate the Celestial Planetarium (on the same floor as the Archivum, all the way to the east) and return to Prospector Loren.
• This enables four quests to obtain the Watchers’ Sigils, which may be performed in any order:
  • Freya’s Sigil – Complete Knock, Knock, Knock on Wood (Defeat Freya while leaving all 3 Elders alive) – This Hard Mode can be triggered by leaving the elders inside her room alive.
  • Hodir’s Sigil – Complete I Could Say That This Cache Was Rare (Defeat Hodir before he shatters his rare cache) – To trigger Hard Mode, you must defeat Hodir in under 3 minutes.
  • Mimiron’s Sigil – Complete Firefighter (Defeat Mimiron after activating his Self-Destruct mechanism) – Hard Mode is activated by pressing big “DO NOT PUSH” button at the back his room.
  • Thorim’s Sigil – Complete Lose Your Illusion (Defeat Thorim while Sif is present) – Hard Mode is activated if you force him into the arena within 3 minutes of the end of the pre-Phase.
• Complete all four quests to enable the quest Algalon from Prospector Loren.
• Simply speak to the Archivum Console to complete the quest, rewarding Celestial Planetarium Key.

This is how you unlock Algalon the Observer Boss Fight.