Re: sun's spectrum

[Leigh Palmer <palmer@sfu.ca>]

It is. Typically an optical pyrometer has an incandescent wire heated
by a current. It is placed at the focus of a telescope and an image of
the source to be measured is superimposed upon it. The wire appears
relatively bright or dark against the image depending on whether it is
hotter or cooler than the object being measured. It disappears at
equilibrium (unless one has switched in a filter to extend to a range
higher than can be reached with the incandescent wire).

> I was not aware of a line radiator in an optical pyrometer.  I thought it was
> just a matter of matching two continuous sources??
>
> On Fri, 30 Jan 1998 19:33:27 -0800 Leigh Palmer said:
> > > The condition for extinction of an emission (or absorption) line is equality
> > > of the temperature of the continuum radiator and that of the thermally
> > > excited
> > > line radiator.
> >
> > ...and that, by the way, is the principle of
> > operation of an optical pyrometer.
> >
> > Leigh