Re: [APML]: Color Film and Filters

[joneil@obs.empath.on.ca (Joseph O'Neil)]

sdilling@ford.com (Stephen Dillinger) writes:
> 
> A simple visual test would be to look at a *white* card in sunlight and see
> what sort of tint you notice.  Strongly colored objects shining by reflected
> light are not representative of the night sky.

  I am trying to follow this - earth based colour is due to sunlight from 
a single source (the sun) and reflected light of an object.

  In the sky, astronomical objects are not always from a single source, 
but from many sources (billions of suns in a galaxy).  Also, colour in 
astronomical objects is due not to reflected light, but emmitted light.

   Therefore, photo filters for  daylight earth use are based on a 
totally different situation that astro-photo filters.  Have I got it 
right?
joe