Skyrim bone altars locations?

[tickle gamer]

Hi All! Well, I'm back at playing Skyrim. I am playing as a Necro-mage.

I have a perk tree mod installed, and just got the "Bone Collector" perk. Can someone tell me the location of the alters? I know about the one at Windhalm.

I've done a search online, but came up dry.

 

[tickle gamer]

For anyone else having this issue. I don't know exactly how it happened, but now the alters are marked on the map.

I am guessing it might have been reading one of the conj skill books.