  We present results from a NuSTAR observation of the Crab made at a large
off-axis angle of 1.5\degree. At these angles X-rays do not pass through the
optics, but rather illuminate the detectors directly due to incomplete
baffling. Due to the simplicity of the instrument response in this
configuration and the good absolute calibration of the detectors, we are able
to measure the absolute intrinsic flux of the Crab to better than 4%. We find
the spectral parameters of the powerlaw to be Gamma=2.106 +/- 0.006, N=9.71
+/-0.16, in agreement with the values measured 42 years ago by Toor & Seward
(1974). This suggests that the observed variability of the Crab is not part of
a long term trend, but instead results from fluctuations around a steady mean.
The NuSTAR observation also enabled improved measurement of the detector
absorption parameters without the added complications of the mirror response.
