Mathematica notebook not working

1. The problem statement, all variables and given/known data
I am trying to find Rydberg's constant. I took measurements using a spectroscope and now I want to do a NonLinearModelFit on the following function:

[tex]\theta = \theta_0 + \alpha + \Arcsin{p k - \Sin{\alpha}}[/tex]

Where p is 1/(d*Rh). I know [tex]d[/tex] and so I can calculate [tex]R_H[/tex] if I know [tex]p[/tex]. Problem is, I can not get the fit method to work in mathematica, but I don't see what is wrong.

3. The attempt at a solution

View attachment 24028

Could anyone please take a look?