That veritable master of astrometry, C.G. Tinney, has measured
the radial distortion over the TAURUS field of view to high accuracy. The
form of the radial profile given below supersedes all previous estimates
from Zemax simulations and from inferior measurements by JBH. This
was measured by the displacement of point sources with known positions,
i.e. the matrix mask. D.H. Jones confirms this relation in his thesis from
the FWHM of stars over the full field. Recall for the MITLL detectors
that the pixels are 15um.