1. A method for operating a nuclear magnetic resonance tomography apparatus for acquiring two differently weighted images, comprising the steps of: (a) disposing an examination subject in a constant, uniform magnetic field; (b) in an excitation phase, exciting nuclear spins in said examination subject by emitting a first radio-frequency pulse; (c) in a read-out phase, emitting a plurality of radio-frequency refocusing pulses in succession, each refocusing pulse being followed by at least one nuclear magnetic resonance signal arising from the excited nuclear spins, each nuclear magnetic resonance signal being spatially-encoded by phase-encoding and read-out gradients; (d) sampling said nuclear magnetic resonance signals and entering nuclear magnetic resonance signals lying chronologically closer to said excitation phase into rows of a k-space of a first raw data matrix and entering nuclear magnetic resonance signals lying chronologically farther from said excitation phase into rows of k-space of a second raw data matrix, with fewer rows of said first raw data matrix being filled than of said second raw data matrix after each excitation phase; repeating steps (b), (c) and (d) until all rows of both of said first and second raw data matrices are filled; and producing a first image from said first raw data matrix by Fourier transformation of the nuclear magnetic resonance signals contained therein and producing a second image from said second raw data matrix by Fourier transformation of the nuclear magnetic resonance signals contained therein.