Heroic: The Celestial Planetarium

To complete the quest you take to the right right before the stairs up to Kologarn. Follow the way and just step outside the door at the very end to the left. There's an overseer there witch need to be killed unless you can stealth to the door or just use invisibility as I did. Deliver the quest to the NPC you accepted it from; "Prospector Loren".

Completing this will unlock 4 new quest:

Freya's Sigil
Thorim's Sigil
Hodir's Sigil
Mimiron's Sigil

All those 4 quest rewarding 26 gold and 46 silver each.

To complete those 4 quests you need to kill each of those 4 bosses on hard mode in heroic difficulty, and loot their sigil. When those quests are completed you will problably unlock a quest witch gives you the key for algalons room; "The Celestial Planetarium".

Unlocking the Celestial Planetarium

1. 
   
2. Complete I Choose You, Steelbreaker or I Choose You, Runemaster Molgeim, enabling one Archivum Data Disc to drop (it is not party loot; similar to Key to the Focusing Iris).
3. 
   
4. Accept the quest from the disc and bring it to the Archivum Console, located beyond the Assembly of Iron.
5. 
   
6. After listening to the Archivum Console speak, accept the quest The Celestial Planetarium from Prospector Loren. Locate the Celestial Planetarium and return to Prospector Loren.
7. 
   
8. This enables four quests to obtain the watchers' sigils, which may be performed in any order:
   
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   • Freya's Sigil - Complete Knock, Knock, Knock on Wood.
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   • Hodir's Sigil - Complete I Could Say That This Cache Was Rare.
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   • Mimiron's Sigil - Complete Firefighter.
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   • Thorim's Sigil - Complete Lose Your Illusion.
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9. 
   
10. Complete all four quests to enable the quest Algalon from Prospector Loren.
11. 
    
12. Simply speak to the Archivum Console to complete the quest, rewarding Celestial Planetarium Key.

Strangely, even though Ulduar can now only be run as 10 man normal you can choose to accept either the normal or heroic version of these quests. I took the heroic just to see if it works and it does. All sigils drop and the quests complete despite being heroic and the raid not being!