Ah yes it is reasonable that several other characteristics make the sensor less likely to register photons from the field of view here. (The sensor/lens could a

Ah yes it is reasonable that several other characteristics make the sensor less likely to register photons from the field of view here. (The sensor/lens could also have some spatial frequency response characteristics that filter out non-diffused stars). I don't find it reasonable that there are no stars in that field of view though :)