The Tokyo Atacama Observatory (TAO) is a Japanese astronomical observatory whose construction was completed last year at the top of the Cerro Chajnantor In the Atacama desertin Chile, at a record height of 5,640 above sea levelmaking it the highest observatory in the world. The advantage is that up there the atmosphere is much thinner and therefore represents much less disturbance for astronomical observations, the quality of which is also guaranteed by the fact that the Chilean desert sky is one of the best in the world.
The creation of the TAO, promoted by the Institute of Astronomy ofUniversity of Tokyo (Institute of Astronomy, UTokyo), lasted well 25 years precisely because of the extreme conditions of the site and the logistical difficulties linked to the high altitude and isolation.
The main instrument of this observatory is a telescope from 6.5 m of diameter optimized for the observation of visible and infrared light. The altitude and conditions of the site were selected specifically for infrared observations (in the Atacama region the air is extremely dry, therefore very poor in water vapor, which absorbs precisely these wavelengths). Be at 5,640 m it also means that the atmosphere above the observatory is much thinner and with less turbulence.
The extreme altitude presents significant logistical problems: operating at 5,640 m is difficult in itself, but the biggest obstacle for personnel is the harsh environmental conditions. For this reason, the TAO, like other high-altitude astronomical observatories in Chile, also has a base downstream to allow its full remote operation.
The TAO is one of the few observatories in the world capable of operating effectively in the mid-infrared from the ground: for this reason it will be able to make unique contributions especially in the observation of barely visible objects ea cosmological distances (the light emitted by objects at very large distances, in fact, is shifted towards the infrared due to a phenomenon called cosmological redshift). Obviously, even considering the altitude and optimal conditions of the site, it remains a ground telescopein the presence of atmosphere, which although thinner, is not absent as it is for space telescopes.
