  We present a deep, 42.79 hr image of the nearby, edge-on galaxy NGC 4565 in
the
  Beijing-Arizona-Taipei-Connecticut (BATC) 6660A band using the large-format
CCD system on the 0.6m Schmidt telescope at the Xinglong Station of the
National
  Astronomical Observatories of China (NAOC). we obtain a final image that is
calibrated to an accuracy of 0.02 mag in zero point, and for which we can
measure galaxy surface brightness to an accuracy of 0.25 mag at a surface
brightness at 27.5 mag arcsec^-2 at 6660A, corresponding to a distance of 22
kpc from the center of the disk. The integrated magnitude of NGC4565 in our
filter is m6660=8.99 (R magnitude of 9.1) to a surface brightness of 28 mag
arcsec-2. We analyze the faint outer parts of this galaxy using a
two-dimensional model comprised of three components: an exponential thin disk,
an exponential thick disk, and a power-law halo. A total of 12 parameters are
included in our model. We determine the best values of our model parameters via
10,000 random initial values, 3,700 of which converge to final values. The thin
disk and thick disk parameters we determine here are consistent with those of
previous studies of this galaxy. However, our very deep image permits a better
determination of the power law fit to the halo, constraining this power law to
be between r^-3.2 and r^-4.0, with a best fit value of r^-3.88. We find the
axis ratio of the halo to be 0.44 and its core radius to be 14.4 kpc (for an
adopted distance of 14.5 Mpc).
