Wave-lengths of the red lines of neon and their use as secondary standards

Abstract

The spectrum of neon is dominated by a strong group of lines in the red. These are easily produced in an ordinary Geissler tube with very great intensity, and are sufficiently sharp to give measurable interference fringes with long path differences, of 120,000 waves or so. For these reasons the red lines of neon appear to be eminently suitable for use as secondary standards, and in view of the good agreement of the wave-length determinations of a number of observers (especially Burns, Meggers, and Merrill at the Bureau of Standards) they were adopted as secondary standards by the International Astronomical Union in 1922.