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Table 2

Lyα/Lyβ irradiance energy ratio during a solar activity cycle.

Reference Ratio   (σ or %) Mission/Instrument

minimum   activity
Lemaire  et al. (1978) 69  (±30%) OSO8/LPSP
this  work 71 (6) TIMED/EGS-SEE

moderate activity
Donnelly & Pope (1973) 75 (50%) compilation

maximum  activity
this  work 55  ( 4) TIMED/EGS-SEE

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