ok the question is,
Calculate the photons you expect to receive per Angstrom at the focus of a Cassegrain telescope of aperture 30cm for a star of V magnitude 9.0, observed at a zenith distance of 60 degrees. Assume extinction coefficient of 0.15 magnitudes per airmass, reflectivity at each...
To answer your first part, we have
angular momentum L = mvr
energy E = 1/2(mv^2) - GMm/r
rearrange energy equation until you have v = something...
substitute that into L = mvr for v
multiply m into the squareroot and that's your answer.
suppose a mass m reduces its orbital velocity by 2 at some point in its circular orbit, but leaving its direction of travel unchanged at that moment, how does the orbit change? I know the new orbit is elliptical but i have no idea how to get to that conclusion.