def ts_grismc_sim(pixels):
    """
    Simple analytic wavelength calibration for Simulated GRISMC data
    """
    disp = 0.0010035 ## microns per pixel (toward positive X in raw detector pixels, used in pynrc)
    undevWav = 4.0 ## undeviated wavelength
    undevPx = 1638.33
    
    wavelengths = (pixels - undevPx) * disp + undevWav
    
    return wavelengths