Destiny 2's A Matter of Time is the quest you need to complete in Season of Dawn in order to unlock the Sundial activity.
Once you pick it up from Ikora in the Tower, you then visit Osiris in Mercury before powering up an obelisk on Tangled Shore.
What follows is how to complete every quest step - which will eventually see you receive the seasonal artefact and access to the Sundial.
Destiny 2 A Matter of Time quest steps in brief
Here's every step of A Matter of Time:
- Visit Ikora in the Tower
- Visit Osiris on Mercury
- Defeat Cabal on Tangled Shore
- Visit the Tangled Shore obelisk
- Defeating enemies with abilities, Supers and by collecting Orbs of Light
- Visit the Tangled Shore obelisk again to get a Sundial reward
- Visit Osiris on Mercury a second time
- Complete a run of Sundial and get a Tangled Shore obelisk reward
- Visit Osiris one final time to receive the seasonal artefact
The entire quest shouldn't take longer than an hour.
Here's how to do it in detail...
Where to find Osiris's location on Mercury in A Matter of Time
First visit Ikora in the Tower, who tells you of your victory against the Undying Mind in Season of the Undying.
Following that, there's been some Red Legion activity on Mercury, so you'll receive the first A Matter of Time quest step, find Osiris on Mercury.
To find Osiris on Mercury, select the node 'Disturbance on Mercury' from the destination screen - it's not in the patrol space itself.
Approach the Sundial and Osiris will emerge, and give you the next quest step, Recovery Operation, which involves recovering Sundial Components.
Where to get all Sundial Components and find Cabal on Tangled Shore
You now have to get 50 Sundial Components by killing Cabal in the Tangled Shore.
The easiest way to do this is to complete the Trapper's Cave Lost Sector within Four-Horn Gulch, the area to the south-east. Equip a solar weapon and sub-class, and each defeated Cabal within will give you three Sundial Components each - meaning you'll complete this by the time you've finished.
Once done, take the components to the obelisk. It's right next to the south-most fast travel point in the destination.
After that, you then need to power it up further by defeating enemies with abilities, Supers and by collecting Orbs of Light. A little more time intensive this one due to recharge times, but nothing difficult.
Now the Obelisk has been restored, you'll need to return again and interact with it. You'll receive a Major Fractaline Harvest as a reward, and a reward for the next time you run the Sundial.
The next step is to visit Osiris back on Mercury, then complete a round of Sundial Arena.
It's an activity on your destination screen, and works much like Menagerie - it's a matchmade activity with multiple stages, and you cannot fail, so continue playing until you win.
At the end of the encounter, inspect the panel to choose from one of the two rewards you earned at the Tangled Shore Obelisk.
Visit Osiris one final time to get the Season of Dawn artefact, The Lantern of Osiris.
You now have the seasonal artefact, have unlocked the Sundial activity, and have three more quests with Osiris - Recovering the Past, Keeping Time, and Mars: Obelisk Attunement - to complete at your leisure.