Devan produced a lot of images using Poisson Statistics. But he could only see 20% frames with any photon at all. Why, can we not explain this using average number of photons from the sky?
Yes, we can. We get only average of 0.17 photon over all pixels of the detector put together. This gives a probability of ~84% to have zero photons incident on the detector. That is perfectly acceptable! Statistics can be trusted :p