A Two-Meier Vacuum Spectrograph—The construction and operation of an optical vacuum-grating spectrograph capable of accommodating a grating of two meters radius of curvature is described. Means are provided for introducing and removing the photographic plate as well as altering the focus and inclination of the grating while the vacuum is maintained.
Doublet Separations in C ii.—The following doublets in Fowler’s series have been resolved and the frequency separation measured. (2π1 − 3σ)(2π2 − 3σ) Δν =64 in the second order of the grating and 60 in the third order. (2π1 − 3δ)(2π2 − 3δ) Δν =64.5 in 2nd order. For lines λ1335 Δν = 65 and lines λ = 1036 Δν = 62 showing that since the 1036 line belongs to Cii probably 1335 does also.
Doublet Separation in Si iii.—In these series the following doublet is resolved. (3σ1 − 4π) (3σ2 − 4π) Δν = 153.
© 1926 Optical Society of AmericaFull Article | PDF Article
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