I started using this name before blockland and it's been sticking with me for a while.
I was messing around in Microsoft Worldwide Telescope (I think that's what it's called...) and I saw a star named Altair. Thought it sounded cool.
I thought you got it from Assassin's Creed, being that the main character's name is Altair
That's what everyone thinks. Although I think that game is pretty fun, it's not where my name came from.