Quote:
Originally Posted by CraigS
G'Day Steven;
Thanks for that .. very interesting. I'll have to read up more on that one.
Perhaps the compensation by using DRIFT still leaves room for some ambiguity, when looking further out at comets …?...
I should be careful about drawing conclusions about ground based measurements of other CO2 diffusing objects, though. (Like Mars and exoplanet atmospheres).
They also used a gamma ray spectrometer on the Mars Odyssey probe which detected large amounts of Hydrogen ions (from orbit). I believe the conclusion about lots of frozen H2O in the poles, is still inferred from these measurements, however.
Interesting.
Cheers
PS: I still don't get her comment about the space based scopes, though.  |
Craig ,
I'm not drawing any conclusions, simply highlighting how one uses an IR spectrometer in the Earth's atmosphere.
One of the advantages of being close to an object is that it allows a specific region of the object to be analysed without having to significantly reduce the aperture of the detector to screen out the surrounding region. This maintains a high S/N ratio.
Clearly Earth and space based telescopes armed with IR detectors don't have this luxury as reducing the aperture of the detector well below the diameter of the exit pupil will block much of the signal.
Regards
Steven