Non-Common Path Error(NCPE) is one of the factors that limit an Adaptive Optics(AO)system from delivering ultra-high performance. To correct the NCPE associated static aberration, we propose a simple but robust and hi...Non-Common Path Error(NCPE) is one of the factors that limit an Adaptive Optics(AO)system from delivering ultra-high performance. To correct the NCPE associated static aberration, we propose a simple but robust and high-performance pupil-plane based wavefront measurement and correction technique, which can copy a single-mode fiber generated perfect wavefront to the AO system via an iteration optimization process, and the NCPE can be effectively corrected by directly commanding the Deformable Mirror(DM) of the AO system. Compared with the previous focal-plane based approach that uses focal plane based Point Spread Function(PSF) for correction evaluation, the pupil-plane based approach can be reliably and rapidly converged to a global optimization result and provides better performance, in particular for an AO system with a large initial static wavefront error. This technique we proposed can be implemented in astronomical AO systems where extremely high performance is required.展开更多
A telescope with a larger primary mirror can collect much more light and resolve objects much better than one with a smaller mirror, and so the larger version is always pursued by astronomers and astronomical technici...A telescope with a larger primary mirror can collect much more light and resolve objects much better than one with a smaller mirror, and so the larger version is always pursued by astronomers and astronomical technicians. Instead of using a monolithic primary mirror, more and more large telescopes, which are currently being planned or in construction, have adopted a segmented primary mirror design. Therefore, how to sense and phase such a primary mirror is a key issue for the future of extremely large optical/infrared telescopes. The Dispersed Fringe Sensor （DFS）, or Dispersed Hartmann Sensor （DHS）, is a non-contact method using broadband point light sources and it can estimate the piston by the two-directional spectrum formed by the transmissive grating＇s dispersion and lenslet array. Thus it can implement the combination of co-focusing by Shack-Hartmann technology and phasing by dispersed fringe sensing technologies such as the template-mapping method and the Hartmann method. We introduce the successful design, construction and alignment of our dis- persed Hartmann sensor together with its design principles and simulations. We also conduct many successful real phasing tests and phasing corrections in the visible waveband using our existing indoor segmented mirror optics platform. Finally, some conclusions are reached based on the test and correction of experimental results.展开更多
Astronomy is an observation-driven science that utilizes telescopes to obtain information from the universe in order to study the most fundamental scientific questions in the universe.The aperture of the telescope det...Astronomy is an observation-driven science that utilizes telescopes to obtain information from the universe in order to study the most fundamental scientific questions in the universe.The aperture of the telescope determines the number of photons received per second and,therefore,the sensitivity and angular resolution ofthe telescope so people can see farther,and itis possible to see fainter objects in the deep universe with a larger-aperture telescope.At present,there are 19 optical astronomical telescopes in the world whose apertures are larger than 6 m,and 14 of them are in the 8-to 10-m class with a maximum aperture of about 10 m,including two Keck telescopes and the Hobby-Eberly Telescope in the United States,the Gran Telescopio Canarias in Europe,and Southern African Large Telescope in South Africa.Most of these telescopes are general-purpose optical telescopes.These telescopes are mainly owned by the United States,Europe,and Japan and are installed in America,Europe,and Africa,while Asia still does not have a single big telescope so far.展开更多
文摘Non-Common Path Error(NCPE) is one of the factors that limit an Adaptive Optics(AO)system from delivering ultra-high performance. To correct the NCPE associated static aberration, we propose a simple but robust and high-performance pupil-plane based wavefront measurement and correction technique, which can copy a single-mode fiber generated perfect wavefront to the AO system via an iteration optimization process, and the NCPE can be effectively corrected by directly commanding the Deformable Mirror(DM) of the AO system. Compared with the previous focal-plane based approach that uses focal plane based Point Spread Function(PSF) for correction evaluation, the pupil-plane based approach can be reliably and rapidly converged to a global optimization result and provides better performance, in particular for an AO system with a large initial static wavefront error. This technique we proposed can be implemented in astronomical AO systems where extremely high performance is required.
基金supported by the National Natural Science Foundation of China(Grant Nos. 10703008 and 11073035)also partly supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KJCX2-YW-T17)
文摘A telescope with a larger primary mirror can collect much more light and resolve objects much better than one with a smaller mirror, and so the larger version is always pursued by astronomers and astronomical technicians. Instead of using a monolithic primary mirror, more and more large telescopes, which are currently being planned or in construction, have adopted a segmented primary mirror design. Therefore, how to sense and phase such a primary mirror is a key issue for the future of extremely large optical/infrared telescopes. The Dispersed Fringe Sensor （DFS）, or Dispersed Hartmann Sensor （DHS）, is a non-contact method using broadband point light sources and it can estimate the piston by the two-directional spectrum formed by the transmissive grating＇s dispersion and lenslet array. Thus it can implement the combination of co-focusing by Shack-Hartmann technology and phasing by dispersed fringe sensing technologies such as the template-mapping method and the Hartmann method. We introduce the successful design, construction and alignment of our dis- persed Hartmann sensor together with its design principles and simulations. We also conduct many successful real phasing tests and phasing corrections in the visible waveband using our existing indoor segmented mirror optics platform. Finally, some conclusions are reached based on the test and correction of experimental results.
文摘Astronomy is an observation-driven science that utilizes telescopes to obtain information from the universe in order to study the most fundamental scientific questions in the universe.The aperture of the telescope determines the number of photons received per second and,therefore,the sensitivity and angular resolution ofthe telescope so people can see farther,and itis possible to see fainter objects in the deep universe with a larger-aperture telescope.At present,there are 19 optical astronomical telescopes in the world whose apertures are larger than 6 m,and 14 of them are in the 8-to 10-m class with a maximum aperture of about 10 m,including two Keck telescopes and the Hobby-Eberly Telescope in the United States,the Gran Telescopio Canarias in Europe,and Southern African Large Telescope in South Africa.Most of these telescopes are general-purpose optical telescopes.These telescopes are mainly owned by the United States,Europe,and Japan and are installed in America,Europe,and Africa,while Asia still does not have a single big telescope so far.
