טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentYatvetsky Pavel
SubjectPhasing of a Multi-Aperture Telescope on a Nearby Planet
DepartmentDepartment of Physics
Supervisor Dr. Erez Ribak
Full Thesis textFull thesis text - English Version


Abstract

The angular resolution of classical reflecting telescopes is limited by our ability to construct large mirrors. The angular resolution of space telescopes is even more restricted since weight and size are major concerns to a space mission feasibility. These restrictions may be overcome by the use of a segmented mirror as the primary reflecting telescope mirror. Segmented mirrors can be relatively lightweight and offer a major advantage to space telescopes since they may even be folded during space launch to be unfolded in space. There are already several earth based telescopes that use segmented mirrors, but there are no such space telescopes yet. A major obstacle for segmented mirror telescopes is the installation process. For a mirror segment to contribute to the total angular resolution, it must not only be aligned with all of the other segments, but it also must match its phase, producing a single cophased mirror. To achieve phase matching among the mirror segments, they must be arranged precisely up to a fraction of the intended wavelength. Such precision in the optical range is unachievable by purely mechanical means. Therefore some phasing calibration system should be introduced. There are several proposed methods; most use additional hardware such as additional camera at a strategic location or a special kind of lens that is designed for the sole purpose of the phasing calibration. In addition, all of the other methods try to focus on a distant (and usually a bright) star for calibration. This research investigates experimentally a phase calibration method based on the simulated annealing algorithm and makes use of no additional hardware. In addition, it attempts to use a large incoherent light source such as a nearby planet. The ability to use a large incoherent calibration target is very useful for telescopes that point towards earth to be used in various scientific fields such as meteorology, botany and even archeology.