ALMA Starts Observing the Sun


A strong effort has been necessary to protect the antennas from the heat, but in the end they succeeded: ALMA started the observations of the Sun.

The lesson has been learned in the hard way: the Swedish–ESO Submillimetre Telescope (SEST) had a fire in its secondary mirror assembly after the telescope was accidentally pointed at the Sun.

The damage that was inflicted by the fire in the 15 m Swedish-ESO Submillimetre Telescope.


However, this time things went very well, and this week have been released by the ESO a series of images that show the power of this new ALMA capability.

Scientists focused their attention into a well known sunspot, which was observed at 1.25 and 3 millimetres.


This ALMA image of an enormous sunspot was taken at a wavelength of 1.25 millimetres. Sunspots are transient features that occur in regions where the Sun’s magnetic field is extremely concentrated and powerful. They have lower temperatures than their surrounding regions, which is why they appear relatively dark. These observations are the first ever made of the Sun with a facility where ESO is a partner. They are an important expansion of the range of observations that can be used to probe the mysterious physics of our nearest star.

These observations probed different layer of the chromosphere, and opened a new frontier in the study of our precious star. For further details you can read the official press release of the ESO where other interesting images are available.