[Laser] photon flux for magnitude 6 stars

[TWOSIG at aol.com]

This is an interesting topic.  It may not contribute much, but I have  a 
question.  I note that the numbers for photons per second are all based  on 
converting all of the energy output of a star (and our sun was used as a  reference) 
into monochromatic photons near the middle of the visual  range.    I think 
that would be an excellent assumption for  estimating the photons we can see 
from a 6th magnitude star, if only  the energy in the visible spectrum was used 
instead of the total energy  output.  There is lots of spectrum we cannot see 
above and below the  visible.
 
So my question is:  What is the fraction of a star's total energy  output 
that is visible?  If the number is at least 10 percent, then the  numbers in the 
original post should be in the right order of magnitude.
 
 
This topic got me to thinking about "counting photons".  If I want to  
receive voice quality signals, can I expect to be able to do that if my system  
receives 50,000 photons per second?  I figure that for that quality, I need  the 
equivalent of more than 10,000 samples per second, so that only  averages 5 
photons per sample, so my samples range from zero to ten.  
 
That seems far too ambitious even at 100 times that many photons.
 
Still, the idea of estimating the number of photons that I see when I look  
up at a star helps me understand how big of an aperture I need to receive voice 
 signals that look about as bright.
 
 
James
N5GUI