We finally have the two movement axes of the Gran Telescopio Canarias (GTC), the azimuth axis and the elevation axis. In order to move, height-wise, we have a huge ring, a circular and hollow 40- ton box with two structures on the sides, called “trunnions”, which couples the engines allowing for the tube to rotate around the elevation axis.
After mounting the “trunnions", the two sections which complete the circle have been mounted.
The ring will bear the weight of the tube, passing it onto the structure. It will also bear the weight of the instruments installed on the Cassegrain focus and the 4 folded Cassegrain foci.
These foci are located on one side of the ring, simplifying the range of movements that the tertiary mirror will have to perform to resend the beam of light to the instruments. In order to compensate the weight of the instruments on only one side of the ring, a weight system will be used to level the telescope.
The total mass supported by each of the Cassegrain foci is 1000 kg, and the instruments installed will be able to have a length of 2m and a 1m diameter.
Natalia R. Zelman