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Posted by Henry Spencer on November 12, 2005, 6:24 am
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>-> I'd never heard of an imaging spectrometer until now, but they sound like
>-> real workhorses.
>
>Aren't they basically the same as the "spectroheliographs" which have
>been used to take photographs of the sun using light of only one
>selected frequency - usually an emission or absorption line of some
>element - for something like a century now?
Not exactly. For one thing, an imaging spectrometer usually takes a full
spectrum of each image point, instead of just choosing one frequency and
shooting an image there. For another, the usual way to build one shoots a
full spectrum of each point along a slit (as an image, with distance along
the slit on one dimension and wavelength on the other) at once, and you
get a full image by doing that repeatedly while moving the slit (either
mechanically or optically), rather than by taking an image at each
wavelength.
--
spsystems.net is temporarily off the air; | Henry Spencer
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