A new table and approximation formula for the relative optial air mass

The mostly used table of the relative optical air massm as function of solar altitude γ (or zenith angle ϑ=90°—γ) was computed byBemporad [1, 2, 3] using values of the vertical air density profile up to 10 km height as they were known about the turn of the century, and taking the refractive index of the air at ground leveln0=1.000293; this index refers to light of wavelength 0.54 μ (peak of the visible spectrum) and to air of temperature 0°C and...