Observatorium Crafting Leves

[Conradus]

I was going to use these to raise weaving to 50 but was not able to talk to the guy in the middle of town. He said I was too weak to take the leves...but my crafting was like level 40 at the time...but my BLM is only level 30...do you have to raise your main class adventuring to open up crafting leves here?

Basically, yes. You have to do the sidequest "Leves of the Observatorium" that he hands out before you can do any of his leves. This is a level 35 sidequest, and he'll make you do the battlecraft leve "Saving Bessy". Most levemetes have to be unlocked in this fashion.