In September 25th, at 22:57h Local Time, the Javalambre Survey Telescope (JST250) achieved engineering first light.

This is a very important milestone in the project since it is the first time that photons from the Universe, in this case coming from the Polaris star, have gone through the complete optical system of the telescope as it was designed: collected by the 2.55m primary mirror, reflected at the 1.2m secondary mirror, corrected through the complex field corrector of 60cm lenses, and finally successfully focused at the 50cm focal plane of the telescope.

With this milestone, the on-site assembly and integration phase is completed. During the next weeks, pointing, tracking and image quality verification are planned to be carried out with the JST250 verification camera. This camera in turn consists on an opto-mechanical setup with two fast read-out cameras, each one assembled in a different translation stage, thanks to which these can be remotely controlled and located at any position of the large focal plane of the telescope, as well as in perpendicular direction along the optical axis.