Collimation, alignment and focus control of the Pan-STARRS PS1 telescope

Prof. Nick Kaiser, Theoretical Astrophysics at the Institute for Astronomy, University of Hawaii

Wide-field telescopes like those used in Pan-STARRS need to be collimated and aligned to very high precision in order to deliver sub-arcsecond image quality and low PSF anisotropy required by e.g. weak lensing. Errors in positioning of the large optical elements at the tens of micron level (fraction of the width of a human hair) give significant image degradation.

In the discussion, Prof. Kaiser described the techniques using out-of-focus images that have been developed to collimate and align the PS1 telescope. He also briefly described the active control system that was developed to maintain accurate focus of the telescope.

PS1 telescope and dome on Haleakala in Hawai’i. Photo: Institute for Astronomy, University of Hawai’i; Brett Simison