Destiny 2's Lumina questline is no joke. Shaft 13 is just one of the locations where you might end up doing its initial stages, and it can be tricky finding the objective around these parts.
For that purpose, this Lumina Shaft 13 location guide is designed to try and point you in the right direction, should you have to go to the European Dead Zone in order to start the Lumina quest proper. Read on!
Lumina Shaft 13 Treasure
The map and the screenshot posted above should help you out a fair bit, if you're leaping into the quest headfirst with no context added, but here's a bit more juice to get you going. The System Positioning Device may send you to a wide variety of locations, such as Sinking Docks and Spine of Keres, and Shaft 13 of course.
Shaft 13 is - obviously - a shaft in the Sludge region of the European Dead Zone, and since it's a named location on the map, getting into the general area shouldn't pose an issue. This particular location can easily be spotted by keeping an eye out for the Lost Sector symbol drawn outside, but the chest itself won't be there.
Instead, you'll find it just before the entrance to this Lost Sector: turn right and go inside a small room nearby. The chest looks rather unique - more like a safe. Kinda hard to miss, so you'll be good when you're at that point. Good luck!