This is not really the most appropriate forum for my question, but that's where the most binoviewer owners are
When discussing limiting magnitude, practically everybody says that looking by both eyes through a binocular (not binoviewer) provides twice as much light and hence a binocular corresponds in light gathering capability to a telescope of an aperture sqrt(2)
times larger. This should supposedly increase limiting magnitude by 2.5*log(2) = 0.75
for the same aperture.
These statements have always striken me as careless. Brain doesn't just add up the light that comes from two eyes, it makes something very complicated that makes people love binoviewers, even though a binoviewer does not provide any additional light but shares the same amount of light between two eyes.
So my question to all owners of binoviewers who have a computer star atlas that shows accurate magnitudes of faint stars: does use of a binoviewer change telescopic limiting magnitude? Can you see deeper when you use a binoviewer as compared viewing without binoviewer and with the same eyepiece? If yes, how much deeper? If we follow the logic that I mentioned above, limiting magnitude through a binoviewer should decrease because the total amount of light is the same minus additional loss in prisms.
Another question: if you look in the binoviewer and then with one eye in one half of the binoviewer, do the faintest stars disappear? If yes, how much you do loose in limiting magnitude?