What would be the highest possible magnitude $m$ of some star that could be viewed with a naked-eye? I am acquainted with this question, but mine is about the ideal conditions.
In order to achieve maximum possible efficiency, I would suggest these points to be considered:
- Find (or better, construct) a monochromatic star with the peak wavelength at the maximum of the human perception ability (in order to avoid bolometric correction and ensure maximum efficiency).
- Find the most experienced astronomer possible with extraordinary viewing abilities.
- Place him out of the atmosphere, therefore in the middle of nowhere (just an astronomer and a star of magnitude $m$).
- Let him use the averted vision technique.
Do you suggest any other points that should be considered? What is then the maximum possible magnitude $m$?