A perfect alignment, at last...

Every year, twice a year (February 7th and November 2nd) the Sun sets behind the Cerro Tololo International Observatory (CTIO) as seen from our own observing room. But not exactly in the same spot, as the length of the year is not 365 days, not even 365.25 days, so there are tiny variations from year to year.

This time, for the first time in over 16 years, we witnessed the "perfect alignment", that is when the centre of the solar disk coincides with the position of the centre of the base of the 4m Victor Blanco telescope, the main instrument of the CTIO.

Now we got to find out when this alignement will be repeated : could it be that we have to wait another 16 years ?...

Photos: Cristian Valenzuela / Observatorio del Pangue - February 7, 2025