The Goggles of Revealing are a craftable headpiece that allows you to see Thaumcraft related information and events. The recipe for these is unlocked with the Goggles of Revealing Research, which is unlocked after you achieve the Unified Thaumic Theory.
Some of the information you are able to see with the goggles equipped are Aura levels, as well as the current level of Flux contamination. The goggles also allow you to perceive Aura nodes that occur around the world.
Another large benefit of using the goggles is that they allow you to view current Essentia values while crafting. Instead of having to guess and remember what you have put into a cauldron, the values and types of Essentia present will appear over the cauldron. This also occurs for Essentia in Alembics and Warded Jars.
There is currently what people call a "bug" where you can't see any node while wearing the goggles. This is actually due to there being no nearby Aura Node. After getting close enough to an Aura Node, you will be able to see how much Vis and Flux it has. After moving away from the Node to where there is no local Aura you will still see the info of the Node.
It can also be added to the Modular Powersuits Helmet using a Tinkering Table but nodes cannot be seen.
Here's a video that shows you how Goggles of revealing work: http://www.youtube.com/watch?v=oRu_k4v9bHs
"The Goggles of Revealing are well suited to divining the mystical world. Not only do they make aura nodes visible to the naked eye, they also allow their wearer to see the mystical interplay between nearby nodes.
The most useful feature of the goggles is that while wearing them, you can see the precise mixture of aspects within a crucible."
|Goggles of Revealing|
Crafting the Goggles of Revealing requires an Infusion Altar and the following materials: four Leather, two Gold Ingots, and two Thaumometers. The recipe also calls for 60 vis, and a latent (in a nearby Warded Jar, Crucible, or Alembic) eight Mutatio, eight Visum, and eight Praecantatio.