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                Spectra of Nebula

The spectra of nebula will show emission lines as contrasted with stars that typically exhibit absorption lines.  Low resolution spectra of the well known nebula M57 is used as an illustration.  The graph was obtained from 600 second exposure.  The spectra of M57 shows energy at discrete green and red wavelengths.  There is no broad background emissions as is seen in stellar spectra.  The blue line at 3869 Angstroms does not clearly show on the graph due to the reduced sensitivity of the detector at that wavelength. Separate graphs of the two regions of interest are shown just below the composite graph.

The emission lines in the green region are:

4861 Hydrogen       relative strength 10   

4958 Oxygen III     relative strength  30

5007 Oxygen III     relative strength 130

The line at 5080 is a cosmic ray hit since it did not reproduce on subsequent exposures

The emission lines in the red region are:

6562 Hydrogen Balmer line (H I )       Relative strength 30

6583 Nitrogen II                                Relative Strength 20

The appearance of the false line at 5080 Angstroms illustrates the need to do several exposures to validate the data. 

Additional nebula spectra will be added in the future.