3 Line identification

Based upon this material we have made line identifications in the traditional way, paying both attention to wavelengths and intensities within the multiplets. The identifications were made with the help of the tables of Moore (1959); for Fe II we also used Johansson's (1978) compilation. In addition we have used the Meinel et al. (1969) catalogue for lines which we could not identify (see notes to Table 2). Some contamination with H$\gamma$ I from city lights was unavoidable and is signaled in Fig. 1. Also [O I] 6300 and 6363 are surely contaminated by emissions from the night sky.

  

Figure 1: Reproduction of CCD spectra of MWC 17. Abscissae: wavelengths in Å. Ordinates: intensities. The continuum is set to unity except for the panel at bottom right. Identifications of the most important lines are provided

Part of the material is reproduced in Fig. 1, where also some line identifications are provided.

In our spectra about 400 emission lines and 19 absorption lines are present. The proportion of emission lines identified is 92$\%$, which is about average for line identification work; 61$\%$ of all identified emission lines could be identified totally or partially with iron lines.

Of nineteen absorption lines we could identify seven with certain or probable interstellar features (Herbig 1975; Herbig & Leka 1991), namely $\lambda\lambda$6203, 6283, 6363, 6446, 6476, 6614 and 6662. The two Na I lines 5889 and 5895 are probably also interstellar, although a circumstellar origin cannot be excluded. From $\lambda\lambda$6203, 6283 and 6614, one can derive values of 0.8, 3.4 and 0.5 for the B-V excess.