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Play a Sound Protoss Observer Observer Witness IV
Hit Points: 40
Plasma Shields: 20
Size: Small
Supply: 1
Cost: 25 75
Build Time: 40
Produced at: Robotics Facility
Requires: Observatory
Base Ground Attack: N/A
Base Air Attack: N/A
Base Armor: 0
Range: N/A
Sight: 9/11 Upgraded
Cooldown: N/A
Production Hot Key: O

These small drones are employed to survey vast wasteland areas or observe and record battles for study within the Archives. Their complex sensor array leaves little energy for defenses, but they can detect cloaked or concealed units with ease, making them invaluable on the battlefield.

Observers that are used for deep-space exploration are often deployed without any defensive systems, but when used in a combat zone they are equipped with a microcloaking field to hide them from the enemy. Like the Arbiter, the Observer does not require any additional energy to maintain the field.

Observers are Robotic spies for Protoss forces on the battlefield. Their huge advantage is the ability to stay permanently cloaked. While Terran players must research upgrades to cloak their Wraiths and Ghosts, every Observer constructed is equipped with a cloaking field without extra cost. No upgrades are necessary to enable this cloaking ability, and there is no need to worry about activating the cloak in combat.

Observers are fairly cheap at a cost of only 25 minerals and 75 Vespene gas, so a Protoss player can usually afford to have several on the battlefield at once.

As the only mobile cloak detector available to the Protoss, Observers are vitally important when attacking a force that has units capable of cloak. The other cloak detector the Protoss possess is the Photon Cannon, but the Cannon is a static defensive structure.

When building Observers, it is a good idea to move the Rally point for the Robotics Facility a short distance away from the building. Because Observers are cloaked, you may find they are hard to spot when they warp in next to the Robotics Facility. By moving the Rally point a little ways away from the building, the Observers should be easier to spot. They can be seen on the mini-map if you have real difficulty finding them.

Can you find the two Observers in this picture? How about during battle?

Where is the Observer?
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Observers are an extraordinary tool in the Protoss arsenal. A Protoss commander can easily see the other species Cloak Detectors (Terran Science Vessels, Zerg Overlords), while the enemy only notices your Observers if they happen to move by it with a cloak detector, cast Scanner Sweep, or see the distortion on the map. Even if detected, the small size of the Observer can make them difficult to see by a player on the screen. This is another reason Observers are such good reconnaissance units.

Place Observers over enemy buildings, Mineral spots, Trees and other Terrain. By doing this, they will be very hard to spot even if the enemy has a detector.

Place Observers over key resource spots to watch for enemy resource expansion attempts. This one of the main uses of the Observer. If you have more areas to check than you have observers, make use of the Patrol command. Way points can also be used to order an Observer to move over multiple areas. Select the Observer, hold down Shift and right click on all the resource spots, then release Shift.

Send Observers with your Carrier and Scout fleets to avoid attack by cloaked Wraiths, and to spot cloaked Ghosts and Burrowed units. Be sure to send multiple Observers with your fleets, especially against a Terran player who might try to Scanner Sweep your Observers. If they destroy one Observer, you want other Observers nearby to keep the Detection coverage intact.

Observers are the best Protoss weapons against Zerg Burrowing. Before building an expansion town, make sure to first scout the location with an Observer. You can detect any burrowed units the Zerg is using as scouts, eliminate them, then create your expansion without tipping off the Zerg.

Observers are fragile. Avoid moving them next to Terran Missile Turrets, Protoss Photon Cannons, and Zerg Spore Colonies, all of which not only can detect the presence of your Observer but also damage or kill it.

Research both upgrades for the Observers in the Observatory as quickly as possible. The upgrades give you much more flexibility when using your Observers.

Observer reveals Lurker Observer Spies on town

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A Lurker was destroying this Protoss town by itself until this Observer comes in to reveal it. Notice all the Protoss units hiding by the Photon Cannon (a good strategy).

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An Observer takes a peek at a Zerg town.

Observers spot each other Observers watches the Resources

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Zileas and Blacklizard's Observers happen to spot each other in the middle.

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An Observer lets this player know that the resource spot is not free and an enemy sneak attack is on its way.

Observers find enemy expansion Observer watching aerial forces

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An Observer finds the enemy trying to start a new town. It's time to attack while there are no defenses.

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When using Carriers, Corsairs and Scouts it is important to protect them with some Observers. This Observer insures that cloaked units will not be able sneak by.

Observer find a weak expansion Expansion is attacked

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The Observer finds an expansion with no defenses and an attack is quickly launched.

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Terran Wraith strength is largely dependant on its power to Cloak. Put an Observer near them and Cloaking is useless.


If you pay careful attention, the graphical disturbance a cloaked Observer creates can be seen. This will alert you to their presence, and you can take the appropriate measures to eliminated the threat


  • Erect Missile Turrets around your town. This should prevent Observers from spying on your town, and also provide a strong air defense.
  • ComSat an area where you know an Observer to be hidden and destroy the Observer easily with nearby combat units.

Missile Turret hits Observer Observer Destroyed

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A Missile Turret keeps an Observer from sneaking into the town.

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The Terrans go Observer hunting. A Science Vessel reveals the Observer and the Valkyrie and Wraiths quickly destroy it.


  • You will need your own Observers to reveal enemy Observers in remote locations.
  • Set up a ring of Photon Cannons around your bases to keep the Observers away.


  • Overlords are usually all the Zerg player needs to counter Observers. Place a ring of Overlords around your bases.
  • Also place Spore Colonies around each base. Not only will Observers be detected but they and any other enemy air unit will be fired upon.

Air Armor Air Armor
Level 1 - 150 150
Level 2 - 225 225
Level 3 - 300 300
Plasma Shields Plasma Shields
Level 1 - 200 200
Level 2 - 300 300
Level 3 - 400 400
Sensor Array Sensor Array
150 150
Increased Observer sight range
Gravitic Booster Gravitic Booster
150 150
Faster Observer movement

Air Armor - Each Upgrade adds +1 to Armor for a total of +3 with all three upgrades.

Plasma Shields - Each Upgrade adds +1 to Shields for a total of +3 with all three upgrades.

Sensor Array - This will allow the Observer to see more of the area around it. This is a must have.

Gravitic Booster - This allows the Observer to move much faster. Another must have upgrade.

Both the Sensor Array and Gravitic Booster upgrades are useful and nearly obligatory when using Observers. The ability to see further and move faster greatly increases the usefulness and flexibility of the Observer.

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