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Your eyes have a maximum dilation of 7mm at age 15. By 50-60 maximum in the average person has reduced to 4-6mm. The light from the 27mm exit pupil is mostly wasted.
With a 2x magnification, you can only use about 2x5mm up to 2x7mm of the primary aperture, ie 10-14mm of aperture. The rest of the 54mm aperture is just counterweight. They should make them 2x14mm.
I had a look through a pair that someone bought at astrofest. I compared naked eye mag limit to the binos in dark sky, dark surrounds and it seemed to me to be delivering views and limiting magnitudes consistent with the smaller aperture.
Joe
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