Center-To Observations of the Sodium D Lines.

Center-to4imb photoelectric observations of the sodium D lines made through the double-pass system at Sacramento Peak Observatory are described For this instrument the scattered-light and resolvingpower corrections are negligible, thus permitting reliable direct observations of the sodium D lines. The measured central intensities of D2 and D2 at the center of the disk are 5 0 and 4.4 per cent, respectively. Profiles of these lines are tabulated with respect to both the continuum at the center of the disk and the local continuum