calc_flux_observed
==================

.. py:function:: luminet.black_hole_math.calc_flux_observed(r, acc, bh_mass, redshift_factor)

   Calculate the observed bolometric flux of a photon :math:`F_o`

   .. math::

       F_o = \frac{F_s}{(1 + z)^4}

   :Parameters: * **r** (*float*) -- radius on the accretion disk (BH frame)
                * **acc** (*float*) -- accretion rate
                * **bh_mass** (*float*) -- mass of the black hole
                * **redshift_factor** (*float*) -- gravitational redshift factor

   :returns: *float* -- Observed flux of the photon :math:`F_o`