Re: sun's spectrum

[Leigh Palmer <palmer@sfu.ca>]

> If we don't see emission lines in the Sun's spectrum then what does
> an H-alpha filter do? There has to be some sort of emission in order
> for the band pass filter to pass it through to your telescope.

Gary explained the function of the H-alpha filter, but he did not
answer your question directly. Emission lines are those for which
the radiant flux is greater than the flux at adjacent wavelengths.
they show as peaks in a spectrum of intensity plotted against
wavelength. The Sun has none to speak of in the visible, and
certainly not in the disk for hydrogen, which is abundant in the
chromosphere. Emission lines of hydrogen can be seen in solar
prominences during a total solar eclipse. In fact they look red.
Those with an intense interest in the solar spectrum might like
to store this URL:  http://mesola.obspm.fr/form_spectre.html

Leigh