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Cosmic Observatory CM Guide

Published Nov 1, 2023 Updated Jan 27, 2024
Aly writer

Face the Wizard of the Celestial in the Cosmic Observatory in Challenge Mode.

  • Failed CC of Dagda fails the strike.

  • Five main phases, four unique, with three split phases at 75%, 50%, and 25%.

  • Stack into the green arrow and circles and spread out orange circles and numbers.

  • The special action key is a projectile used to kill the Soul Feast and and remove Demonic Aura from Dagda.

  • Turn shaders down to avoid being blinded by the bright Planet Crash attack.

  • Show player names can be helpful if anyone takes 10 stacks of Residual Anxiety

  • Timer of 10 minutes to complete strike.

When first setting up to fight Dagda you'll need to consider:

  • Bring a lot of CC
  • Favours ranged and condi DPS
  • Some stability can be helpful on split phase.
  • The instance is set to Tyria Time on opening.
Hide Ally Visual Effects

This currently needs to be set to Hide None or Only Show Squad as it is altering the visibility of indicators for spreading and stacking mechanics in Challenge Mode.

Pets & Summons

Some mechanics in this fight will target on player allies. In particular Spinning Nebula on damage builds can be problematic as ranger pets, mechs and necromancer minions (mesmer clones untested) will gain stacks of Debilitated from the projectiles. If they are melee range of the spin they will take 3 stacks near instantly. They do not gain stacks from standing in the wrong segment of Demonic Blast.

Dagda, Wizard of the Celestial
Dagda, Wizard of the Celestial
100% to 90%

Dagda starts the strike with 10 stacks of Demonic Aura. The fight starts when a players gets Dagda in combat, who opens with Planet Crash. Each Defiance Bar must be broken or it is an instant wipe.

When the bar breaks, Dagda is briefly Exposed and Planetary Weight is applied to her.

Subsequent breaks, and failed Shooting Stars or Meteor Crash, will apply a stack of Planetary Weight, increasing her Defiance Bar capacity.

Each stack of Demonic Aura reduces damage taken by Dagda by 10%. When all stacks are removed Demonic Aura Timer is applied for 20 seconds before 10 stacks of Demonic Aura are reapplied.

Purifying Light will be deployed to the field and Dagda will start her auto attack chain will begin her auto attack visually identified with striking from left, right, overhead: Strike, Vengeful Strike, Starburst. Strike and Vengeful Strike are melee attacks; Starburst is a melee attack in her hitbox and a ranged projectile outside it - standing at the edge of the hitbox can result in being hit by both versions. This is her repeating chain this phase:

  • Auto x1 Shooting Stars (Green Arrow)
  • Auto x1 Shooting Stars (Green Arrow)
  • Auto x1 Spinning Nebula

This repeats until 90% HP when Dagda casts Demonic Blast.

Planet Crash

Planet Crash

Dagda channels a massive attack, break the defiance bar or fail the strike.

Purifying Light

Purifying Light Three copies shown with overlapping mechanics.

One to five fields will periodically be placed on the field which grant the skill Purifying Light on special action key.

Prioritise use against Dagda as this removes 5 stacks of Demonic Aura.

Purifying Light can kill one Soul Feast and turn its field non-damaging.

Consider using the minimal copies for intial use and collecting the others right before despawn to maximise the speed in removing Demonic Aura as the skill is available for 15 seconds after collection. Watch for the buff icon flashing for the skill expiring

Shooting Stars

Shooting Stars Shooting Stars randomly targets one player, with a target overhead and a green arrow pointing through them. Beware the Shooting Stars. Hide behind your allies! will appear in the middle of the target's screen and red text in chat. There is a 6.5 second window to get a minimum of 5 allies directly between the target and Dagda to mitigate the mechanic. Failure of this mechanic applies one stack of Infirmity to the squad and kills the target. The target should step backwards and stay still.

When overlapping with collecting Purifying Light, non-target supports should be the first choice to handle Demonic Aura.

Spinning Nebula

Spinning Nebula Centre

Spinning Nebula has multiple projectiles coming from the centre, or one fan at the side, and an AOE circle outlined in red below Dagda.

Being hit by a projectile will apply Debilitated up to 3 stacks.

This is not susceptible to projectile control in Challenge Mode, but may be body blocked to shield others or distorted while body blocking to avoid stacks.

Spinning Nebula

Spinning Nebula Side

Demonic Blast

Demonic Blast At 90% HP Dagda goes briefly untargetable and casts Demonic Blast. Step between the orange slices. Failure on this mechanic will apply one stack of Debilitated and 3 stacks Residual Anxiety to each player failing the mechanic and summons one of The Tormented at their location.

It is possible to Evade this mechanic.

Key Mechanic

At reaching 10 stacks of Residual Anxiety players will turn hostile and are Taunted by squad members. After either being hit with (most) Hard CC skills or entering downstate they will no longer be hostile.

If all surviving players reach 10 stacks of Residual Anxiety the strike will instantly fail.

If player name options are not turned on it may not be obvious someone in the squad has turned unless you are the Taunt target as they do not show as enemies. If you have turned it may not be obvious without seeing yellow and red player names.

Revenant CC skills do not consistently work against hostile players.

A note about Demonic Blast/Champion spawns

There is a commonly held belief that players being hit with Demonic Blast increases the number of Champions spawning in the following Split Phase.

This was repeatedly looked at when the guide was originally published, and due to this information persisting in the community, was confirmed again in testing January '24 to have no discernible correlation to being hit by or evading over the damage section of this mechanic.

90% to 75%

Dagda adds Demonic Fever (Spread Circles) into the rotation. This targets the 7 closest players with orange circles. Avoid overlapping another player with the mechanic with the circle before they explode.

Dagda will have this rotation until 75% HP:

  • Auto x2 Shooting Stars (Green Arrow)
  • Demonic Fever (Spread Circles) as Auto x 1
  • Spinning Nebula at centre or the side
  • Demonic Fever (Spread Circles) as Auto x 1
Demonic Fever
Demonic Fever

In current testing runs targets of Demonic Fever are usually the closest 7 players, but there is anomalous data which may be due to skill movement.


Dagda casts Demonic Blast and pushes everyone towards the wall through a damaging field.

One player is targeted by five Soul Feasts that are hard to target for Purifying Light. Players may need to dodge through the spawning circles.

A combination of four, Champion and Elite Tormented, will spawn around the arena. They inflict Torment. The Champions can summon additional Phantoms, which are immune to damage and must be CCed to kill them directly. The Champions use Tornado of Torment to Launch players backwards.

Ideally, position between the stairs on the outer instance to avoid foes leaping out of player bounds.

Kill all foes to progress.

Demonic Blast with push

Demonic Blast Demonic Blast is now combined with a pushback and a damaging field around Dagda.

Exit the field as quickly as possible, dodging the blast segments if needed. This mechanic can be dangerous when overlapping mechanics in later phases and DPS may need to be adjusted to avoid phasing.

Soul Feast

Soul Feast Soul Feast targets a single player that receives a red chat and mid-screen message: You are targeted by Soul Feast. Run! Five will spawn, one per second, and follow the player until they either expires in 15 seconds from their individual spawn, or a player hits each of them with Purifying Light.

Anyone hit by an active Soul Feast, not its residual field, gains a stack of Residual Anxiety.

Soul Feasts under Dagda will apply one Demonic Aura stack per tick.

On phase change it is possible to have this mechanic on two targets at once.

75% to 50%

Dagda returns with 10 stacks of Demonic Aura and a new rotation. Use the voice lines for Demonic Pools a cue for avoiding Spinning Nebula as the next attack.

January 2024 this has been noted to have changed from the original rotation to have overlap and has been updated

Charging Constellation (Numbers) (this happens in isolation once, then repeats attacks below):

  • Auto x 2, Shooting Stars (Arrow)
  • Meteor Crash (Green Circles) with Auto x 1
  • Auto x 1 with Demonic Pools (Outer Orange) and alternates centre/side Spinning Nebula
  • at centre, Soul Feast
  • Auto x 1, Demonic Fever (spread circles) with Charging Constellation (Numbers)

This continues until 50% HP.

Demonic Pools:

Demonic Pools Pools with overlapping mechanics.

Demonic Pools are 8 large orange circles, which change to have the same appearance as Soul Feast. They spawn harmlessly near the outer edge in a set pattern for a couple of seconds before becoming damaging fields for a total of around 20 seconds when they despawn. Standing in the AOE applies Residual Anxiety.

For this mechanic, Zojja uses the voice lines:

  • Don't stand in that or we'll lose you!
  • Get out! Get out!
  • Get outta that! It's making you vulnerable!

Charging Constellation:

Charging Constellation Charging Constellation (Numbers) targets 5 players who are sequentially attacked in turn with a range attack by Dagda, which will apply Extreme Vulnerability to the target and nearby players.

Spread enough so the attacks cannot hit more than one player.

This mechanic has orange edge of screen borders and red squad UI borders.

The damage and Extreme Vulnerability application can be negated with Aegis & block. Evade testing has it likely, but incomplete due to boon overlap. It can be sidestepped with low ping.

Meteor Crash:

Meteor Crash Meteor Crash places green circles under two players. Three players are required to be in the circles, which may be stacked, for success of the mechanic.

More players is not currently detrimental in testing, but visual indicators show there are an excess of people.


Dagda casts Demonic Blast and pushes everyone towards the wall through a damaging field.

  • Any Charging Constellation (Numbers) or Shooting Stars (Green Arrow) in progress should not execute as she changes animation, but treat them as if they will.

  • Demonic Fever (Orange Spread) and Meteor Crash (Green Circles) are likely to execute as the damage is not tied to her animation. Soul Feast will also persist.

This repeats the previous split phase with the foes increased to five.

It is possible for a single target to carry Soul Feast into this phase and be chosen again, to have a total of 10 following them.

50% to 25%

Dagda returns with 10 stacks of Demonic Aura and a new rotation until 25% HP:

  • Auto x 2, Shooting Stars (Arrow)
  • Meteor Crash (Green Circles)
  • Auto x2, Demonic Pools (Outer Orange)
  • Auto x 1, Spinning Nebula centre
  • Soul Feast
  • Auto x2, Rain of Comets
  • Demonic Pools (Outer Orange) overlapping Auto x 2
  • Planet Crash
  • Charging Constellation (Numbers)
  • Auto x 2, Shooting Stars (Arrow)
  • Auto x2, Demonic Pools
  • Auto x 1, to side Spinning Nebula
  • to centre Soul Feast
  • Auto x2, Rain of Comets
  • Demonic Fever (Spread Circles)

Dagda casts Demonic Blast and pushes everyone towards the wall through a damaging field.

  • Any Charging Constellation (Numbers) or Shooting Stars (Green Arrow) in progress should not execute as she changes animation, but treat them as if they will.

  • Demonic Fever (Orange Spread) and Meteor Crash (Green Circles) are likely to execute as the damage is not tied to her animation. Soul Feast will also persist.

This repeats the previous split phase with the foes increased to seven.

25% to 0%

Dagda returns with 10 stacks of Demonic Aura and the same rotation as the previous phase until 0% HP

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