Infared Telescope questions

4. IR sensors (telescopes) are specially suited for studies of gas bodies like nebulae or to view through gas bodies that other wavelengths (visible & Ultra Violet) can't penetrate. This was the experience gained from the study of Venusian surface, being blocked by thick Sulfurous & CO2 clouds. Yet, atmospheric gases of Earth absorb the incoming IR light, attenuating the picture. hence it is desirable to go to high altitudes like those in Hawaiin Islands or even satellites above the atmosphere.
5. Astrophysics concerns with electromagnetic spectrum of which IR is a part, while visible region too is one. While Visible region is a sliver hardly 1 Octave wide, IR spans nearly 9 Octaves and so is a rich source of information to which we hardly opened our eyes, thanks to the advances made in modern Astronomy. IR spectroscopy is inherently ana analytical tool, much like the other (visible) spectroscopy. All the principles employed in the visible region (including the Doppler based Red and Blue shift) are applicable in IR too and have far greater promise. I wouldn't wonder if several IR bright stars get discovered in nearby areas (there might be an IR star nearer than Proxima Centauri, who knows!)that we couldn't see as they are invisible in visible region with their feeble visible energy pulling down their apparent magnitudes to 16 or 20.