Night Sky Emissions

最終更新 : Jun. 14, 2004.

Units

1 Rayreigh
= 1.58 x 10^-7 [λ^-1 J m^-2 sr^-1 s^-1]
= 7.96 x 10⁸ [photons m^-2 sr^-1 s^-1]
= 1.87 x 10^-2 [photons m^-2 arcsec^-2 s^-1]

Photon数
1 [photon] = 1.986 x 10^-16 [λ^-1 J]

1 [arcsec²] = 2.35 x 10^-11 [str]

Relations

Photon number ratio
N(night sky)/N(m_AB)
= 3.4 x 10^-13・I_sky・(λ[Å]/Δλ[Å])・ 10^mAB/2.5 ・S
= 3.4 x 10^-13・I_sky・R・10^(mAB/2.5) ・S
I_sky [Rayleigh] : sky emission intensity
m_AB : AB magnitude of the object
λ[μm] : wavelenth
Δλ[Å] : wavelength resolution
R=λ[Å]/Δλ[Å] : resolution
S [arcsec²] : aperture

Night Sky Emissions

Emitter	Wavelength(Å)	Intensity (R)
OI	5588	250(Night), 180(Twilight)
OI	6300-6364	100(Night), 1000(Twilight)
HI	6563	15(Night)
NaI	5890-5896	30(Summer, Night), 1000 (Summer, Twilight)
NaI	5890-5896	200(Winter, Night), 5000 (Winter, Twilight)
O₂	8645	500(Night)
OH	8342	2000(Night)

from Allen's Astrophysical Quantities 4th ed. §11.25

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秋田谷洋