After finishing the quests "Seeking Disclosure" and the optional quest "Scroll Scouting", you bring the two Elder Scrolls (Elder Scroll: Blood, Elder Scroll: Dragon) to Dexion Evicus, the Moth Priest. But he says he cannot help you with the scrolls any longer, for he has gone blind.

Dexion offers an alternative way to read the scrolls. Scattered across Tamriel are secluded locations known only as Ancestor Glades. There's one in Skyrim, in the Pine Forest. Performing the Ritual of the Ancestor Moth within the glade should provide you the answers you seek. The ritual involves carefully trimming the bark from a Canticle tree which will in turn attract Ancestor Moths to you. Once enough of the moths are following, they'll provide you with the second sight needed to decipher the scrolls.

Ask Dexion how to carefully gather the bark. He says that in keeping with tradition, you must use a specific tool in the Ancestor Glade, an implement known as a Draw Knife. Every Moth Priest is taught this ritual, but few ever get a chance to perform it. You should consider yourself fortunate if it works for you.

Ask the Moth Priest if you need to read the scrolls in any particular order. He tells you that from what he saw in the vision, the Elder Scroll which foreshadows the defiance of the gods with the blood of mortals is the key to the prophecy.

Elder Scroll (Sun) is added to your inventory, and your map is updated. You should now be carrying all three Elder Scrolls:

Elder Scroll (Blood)
Elder Scroll (Dragon)
Elder Scroll (Sun)

The next quest starts:

Unseen Visions
After discovering that Dexion has become blind, I've had to secure alternate means to decipher the Elder Scrolls and locate Auriel's Bow. It's been suggested that I might be able to read the Elder Scrolls myself if I use an ancient technique performed by the original Moth Priests. I'm now on my way to a place known as the Ancestor Glade to discover the origin of the mysterious ritual.

Objectives
Find a Moth Priest's knife.

You can ask Dexion some more questions about Moth Priests, the Elder Scrolls, and his blindness. You find out he did not prepare enough for the reading of the first scroll, which is why he went blind so early. Also learn about the relations between moths and the Elder Scrolls. The voice of the Ancestor Moth has always been an integral part of reading the Elder Scroll. Moth don't literally read the scrolls, but instead they maintain a connection to ancient magic that allows the Moth Priest to decipher them. Dexion believes that you were destined to hear the ancestral chorus that the moths produce.

Exit castle Volkihar and locate the Ancestor Glade on the map. It is located near Falkreath, so fast travel to Falkreath and then trek east to get to the Ancestor Glade. Alternatively, you could travel to Pinewatch and from there go southwest. Either way, locate a path leading up to the mountain. You will have to climb the steep road for a while, before reaching a cave which is the entrance to the Ancestor Glade.

Enter the Ancestor Glade.