Recently reported measurements of the absorption band strength (i.e., the Einstein B-coefficient for absorption) for the transition O-2(X(3) Sigma g --> a(1) Delta g) at 1.27 mu m, when correctly reanalyzed in this paper, indicate that the Einstein A-coefficient for spontaneous emission of radiation is 1.47 x 10(-4) s(-1). This is a factor of 1.75 smaller than the value of 2.58 x 10(-4) s(-1) that has been used almost exclusively in the aeronomy field for the past 30 years. The determination of the new A-value is reviewed, with an emphasis on the derivation of the appropriate ratio of the degeneracies of the upper and lower states of this transition. The new A-value implies that ozone concentrations as inferred from measurements of O-2(a(1) Delta g) emission must be increased significantly in existing databases and also that the efficiency of solar heating in the Hartley band of ozone is larger than previously calculated.