Infrared observations

IR astronomy took-off relatively recently, with the advent of rockets and satellites to get the instruments above the atmosphere. The water vapour in the atmosphere will otherwise absorb a large fraction of the IR light. The construction of the camera for near IR observations is challenging. They need to be cooled, since otherwise the main source of signal is thermal radiation from the camera itself. I suspect that, again, a major driver behind their construction was not really astronomical, but over the past 10 years or so, it seems that much of the technology has becomes available to the astronomers.

IR-observations share with radio the great advantage not to be strongly absorbed by dust. In fact, much of the visible and UV-light absorbed by dust grains, is re-emitted in the IR and sub mm. And so we can use IR to probe the dust and look deep inside star forming regions. We thank the DIRBE instrument on the COBE (Cosmic Background Explorer) satellite for one of the best views of the Milky Way.