RE: ATM fiber optics

["Antonio de Ugarte Postigo" <ugarte@mad.servicom.es>]

Hi Mitch
>Second, Is there a (useful) difference between a solar spectrograph and
>a stelar spectrograph? (i.e. bright source versus dim source).

They are essetially the same thing: an entrance slit, a colimator lens (or
mirror) a light dispersor (prism or grating) and a focusing device. The real
difference comes when you thinck about the amount of ligh you are going to
disperse. With the Sun you have so much light that you can have an enormous
dispersion with very short exposures. With other stars you'll have to expose
for hours to get just a fraction of the dispersion. Another fact is that as
a star is just a point of light you can avoid the use of the slit, not the
case of extended objects.

>Third, how are your going to get the light to enter the fiber, and guide
>the scope during the exposure?
>
>Mitch
We are planning to proyect the light with a refractor onto a screen where
there will be some fibers that will conduct the light to the spectroscope.
We will use the guiding motors of a small mount. We don't need a really good
guiding as the exposures will be relatively short.

Antonio de Ugarte Postigo