  We investigate the independent points in the sky require to search the
periodic gravitational wave, assuming the noise power spectral density to be
flat. We have made an analysis with different initial azimuth of the Earth for
a week data set. The analysis shows significant difference in the independent
points in the sky for the search. We numerically obtain an approximate relation
to make trade-off between computational cost and sensitivities. We also discuss
the feasibility of the coherent search in small frequency band in reference to
advanced LIGO.
