  The third year of observations with the Python microwave background
experiment densely sample a $5.5^o\times 22^o$ region of sky that includes the
fields measured during the first two years of observations with this
instrument. The sky is sampled in two multipole bands centered at $l \approx
92$ and $l \approx 177$. These two data sets are analyzed to place limits on
fluctuations in the microwave sky at 90 GHz. Interpreting the observed
fluctuations as anisotropy in the cosmic microwave background we find flat band
power estimates of $\delta T_l\equiv \sqrt{l(l+1)C_l/2\pi }% =54_{-12}^{+14}\mu
K$ at $l=92_{-24}^{+37}$ and $\delta T_l=58_{-13}^{+15}\mu K$ at
$l=177_{-58}^{+66}$. Combining the entire three year set of Python
observations, we find that the angular power spectrum of fluctuations has a
spectral index $m=.02_{-.16}^{+.18}$ and an amplitude $% \delta
T_{l_e}=53_{-11}^{+13}\mu K$ at $l_e=145_{-74}^{+59}$ for the functional form
$\delta T_l=\delta T_{l_e}(l/l_e)^m$. The stated uncertainties in the
amplitudes and spectral index represent 1$\sigma $ confidence intervals in the
likelihood added in quadrature with a 20\% calibration uncertainty and an
estimate of the effects introduced due to imperfect overlap of the beams on the
sky. The limits of $l$ are determined from the full width at half maximum of
the window functions.
