This quest has a quick guide, found here, which briefly summarises the steps needed to complete the quest.

The Observatory Quest is a standalone quest where you must help the professor of the Observatory repair the building and restore it to its former glory.

Official description

Walkthrough

Start point:	Talk to the Observatory Professor in the Observatory Reception Room north of Castle Wars.
Member requirement:
Official difficulty:	Novice
Length:	Short to Medium (depends on how quickly you find the kitchen key)
Requirements:	Level 10
Items required:	Items from the toolbelt do not need to be listed unless that version won't work, or aren't automatically added to it. 3 planks A bronze bar Molten glass Recommended: An antipoison potion A Ring of duelling
Enemies to defeat:	Goblin Guard (level 42) (Optional) Poisonous Spider (level 31) (10 approx.)

Getting There

The fastest way to get to the Observatory is to use a ring of duelling to teleport to Castle Wars and just go up north. Alternatively, you could use the Spirit Tree to the battlefield and walk south.

Another easy way to get to the Observatory is using the Ardougne Teleport (after you have done the Plague City quest) and go south-west to the Observatory.

Starting Out

Talk to the professor in the house near the Observatory and mention the observatory. He will tell you that the telescope is broken and refer you to his assistant.

The assistant will ask you to collect some material for repairing the telescope and you need to give the first three items to the professor before you can start creating the lens mould.

• A bronze bar
• 3 planks
• A molten glass
• 1 lens mould (created during the quest)

The lens mould

Talk to the assistant, then the professor to turn in each of the items. They will tell you that they can't make a new lens because the goblins have stolen the lens mould.

Leave the house and head east to one of the abandoned buildings. There is a super antipoison (1) respawn in the south eastern abandoned building, which respawns about every 48 seconds. If you didn't bring antipoison, take two or three of those with you for when you encounter the poison spiders.

Climb down the stairs in the west building, which leads to a maze-like dungeon. Each dead end contains a chest. One of these chests contains the goblin kitchen key (the location is different for every player), the other chests contain nothing, a single dose of anti-poison or most likely a level 31 poison spider, which will likely poison, even if the attack does no damage. Keep searching the chests until you find the kitchen key.

Go back to the staircase you entered the dungeon from, but do not exit the dungeon. Instead, go east, north, and then west and keep on going west until you see sleeping guard guarding a kitchen. Once you prod him, he will turn into a level 42 goblin guard. You have to either kill him or bring him far enough away from the gate to get into the kitchen. Once you get into the kitchen, inspect the goblin stove. They have appeared to be using the lens mould as part of their cooking.

Head back to the professor. The professor will now ask you to make a lens for him. Do as he says by simply using the molten glass with the lens mould. Talk to the professor again and he will tell you to meet him at the other side of the observatory.

The Observatory

Head back down the stairs in the abandoned building where you got the key and lens mould from. Follow the path around and up the stairs, then talk to the professor and watch the long cut-scene of him fixing the telescope. Go up the stairs and talk to the professor again, he will tell you to have a look through the telescope. Talk to the professor after looking through the telescope. Tell him what constellation you saw.

Name	Picture	Name	Picture
Aquarius		Aries
Cancer		Capricorn
Gemini		Leo
Libra		Pisces
Sagittarius		Scorpio
Taurus		Virgo

Congratulations, quest complete!

Rewards

• 2 Quest Points
• 2,250 experience
• An uncut sapphire (not the constellation reward)
• 875 experience in , , , or (random)
• Depending on the astrological sign you see through the telescope, you will receive one of these items:
  • Maple longbow (Sagittarius)
  • Weapon poison (Scorpio)
  • 3 Law runes (Libra)
  • Amulet of defence (Cancer)
  • Black two-handed sword (Gemini)
  • Super strength potion (1) and an Uncut sapphire (Taurus)
  • About 25 Water runes and an Uncut sapphire (Aquarius)
  • 3 Fish pies or 3 Tunas (Pisces)
  • Uncut sapphire (Aries, Leo, Virgo, Capricorn, Gemini)
• 2 extra spins on the Squeal of Fortune
• You can talk to Historian Minas at the Varrock Museum to receive 5 Kudos.

Music unlocked

• Serenade - You do not have to do this quest to unlock this music, though it will be unlocked if you are in the starting area of the quest.
• Expedition - Can also be unlocked during Troll Stronghold quest.

Spirit of Scorpio

Should a player look through the telescope again after the quest is completed they will see Scorpio. Upon speaking to the Professor's assistant, he will reveal that his name is Patrick, and that the Professor's name is Mambo-duna-roona, though the Professor will deny that his name is Mambo-duna-roona. The Professor's assistant will thank you for having made his life easier, and give you a jug of wine.

The Professor's assistant will also mention a book to be found on a nearby table. The book of astronomy will mention Scorpius' grave. The Professor's assistant will tell you to look north of the Observatory; the location you need to go to find Scorpius' grave is considerably far north of the Observatory. Travel past the abandoned building where you picked up the super antipoison (1) near the goblins, and keep going north until you see some level 24 ghosts to your left near the entrance of the Ourania runecrafting altar. The spirit of Scorpius is located in this area with the ghosts. After a brief conversation, the spirit of Scorpius will give you an unholy mould and request you return when you are worthy. Take the mould and a silver bar and make an unholy symbol. Then return to the grave so the spirit of Scorpius can bless the symbol.

Trivia

• The entrance to the Observatory Dungeon used to be at the quest starting house. It has been moved due to an update and now its located on the hill.
• Upon completing this quest one's Adventurer's Log will read: "I soon fixed the professor’s telescope after it was destroyed by those pesky goblins."
• If you fight the kitchen guard, then leave before killing him, when you return there will be two kitchen guards.
• When you entered the kitchen, you used say to yourself "You had better be quick" rather than "I had better be quick". This has since been fixed.
• When you talk to Patrick after he gives you some wine, you will talk to him as though if you are drunk, even if you haven't drank the wine yet.
• After completing the quest, if you talk to Juna, your character will say, "...And when I had fixed the telescope, I looked through and saw the stars." to which she replies, "It is long since I have seen the stars..."
• If you take the lens off the goblin stove it disapears for other players.