Wujen wrote:Ooc: Astral Sight would make the box look "translucent" if something alive were in it, just as the rest of the world fades out except for the aura of living things, kind of like clothes don't stop you from seeing a person's aura.
5e doesn't really do a great job of explaining what you can see on the astral plane (at least not in the sections I have found on the subject, but indexing is awful in the books, so I may have missed something). All it really has to say on the matter is:
Living things in general are not active on the astral plane but still cast a reflection of themselves there. This reflection is called an aura; it appears as a shining, vibrant, colorful luminescence. Any non-living objects appear as faded semblances of their physical selves; grey, lifeless, and intangible.
Anything active on the astral plane, including spirits, active foci, dual-natured beings, etc., has a tangible astral form. These forms are more colorful and brighter than auras, as they are astrally “real.” The Earth has an astral form, and many regard this as proof that the planet as a whole is a living entity apart from (or made up of) the creatures that inhabit its surface.
It does not say that non-living things are translucent, but it doesn't not say that either. Just says they are intangible, which means you can go through them. But according to 4e's street magic, "non-living objects do make opaque shadows on the astral which can block line of sight," also "mirrors and glass on the astral plane are opaque and non-reflective, since those are concepts associated with visible light." So I wouldn't think you could see through a box on astral because it has no emotion tied to it. The reason you can see through clothing is because it is a personal item that absorb's the owner's emotion (which is what you are "seeing"). I suppose in theory you could project and poke your astral head through the box to see what is inside if it were a large enough box with enough space inside for you to see something other than shadow. Hitting something solid would be a good indicator that there's something magic or living in there though since those are tangible.
Mostly I reference the wiki entry on Astral Space. It cites the 5e book at the bottom so while 5e may not specifically restate the stuff above, I don't believe it has contradicted it either so it's what I am going with.