The nebular spectra of two slow novae, DQ Herculis and RT Serpentis.

The spectrum of Nova Herculis has been measured in the region λλ 3200-6700, and many new lines have been identified. The character of the spectrum has not changed greatly since the observations by Adams and Joy in 1935-1936, but the increased separation between the two visual components of the Nova has now made it possible to observe separately the two spectra. The ionization seems to be identically the same in the two objects, but some differences in the structure of the lines was noticed. Spectra taken with the slit along the major axis of the elongated image show a marked depression between the two outside components of the emission lines, while at least the preceding component of the binary shows a fairly strong central component between the two outside components. The observations are sensitive to conditions of seeing, and it is not possible at this stage to unravel the true nature of the spectroscopic structure of the lines.
The spectrum of Nova Serpentis, which had an outburst in 1909 and which is known to have developed abnormally slowly, was last described by Joy in 1931. Since that time the spectrum has undergone marked changes: the lines of [Fe III], which were strong in 1931, are very weak on our spectrogram. Instead, [Ne III], [Ne V], and [Fe VI] are strong, in addition to H, He I, He II, and [O III].