Elliott Thorn, Research School of Astronomy and Astrophysics – The Australian National University, Visa Korkiakoski, Research School of Astronomy and Astrophysics – The Australian National University, Doris Grosse, Research School of Astronomy and Astrophysics – The Australian National University, Francis Bennet, Research School of Astronomy and Astrophysics – The Australian National University, Francois Rigaut, Research School of Astronomy and Astrophysics – The Australian National University, Celine d’Orgeville, Research School of Astronomy and Astrophysics – The Australian National University, Josephine Munro, Research School of Astronomy and Astrophysics – The Australian National University, Craig Smith, Electro Optic Systems (EOS)
Keywords: SCIDAR, atmospheric turbulence, scintillation, space situational awareness
Abstract:
The Research School of Astronomy and Astrophysics (RSAA) in conjunction with the Space Environment Research Center (SERC) has developed a single detector stereo-SCIDAR (SCIntillation Detection And Ranging) system to characteristic atmospheric turbulence. We present the mechanical and optical design, as well as some preliminary results. SERC has a vested interest in space situational awareness (SSA), with a focus on space debris. RSAA is developing adaptive optics (AO) systems to aid in the detection of, ranging to, and orbit propagation of said debris. These AO systems will be directly improved by measurements provided by the usage of the stereo-SCIDAR system developed. SCIDAR is a triangulation technique that utilises a detector to take short exposures of the scintillation pupil patterns of a double star. There is an altitude at which light propagating from these stars passes through the same “patch” of turbulence in Earth’s atmosphere: this patch induces wavefront aberrations that are projected onto different regions of the scintillation pupil patterns. An auto-correlation function is employed to extract the height at which the turbulence was introduced into the wavefronts. Unlike stereo-SCIDAR systems developed by other organisations — which utilise a dedicated detector for each of the pupil images — our system will use a pupil-separating prism and a single detector to image both pupils. Using one detector reduces cost as well as design and optical complexity. The system has been installed (in generalised SCIDAR form with a stereo- SCIDAR upgrade scheduled for nest year), tested and operated on the EOS Space Systems’ 1.8m debris-ranging telescope at Mount Stromlo, Canberra. Specifically, it was designed to observe double stars separated by 5 to 25 arcseconds with a greater magnitude difference tolerance than conventional SCIDAR, that conventional difference being roughly 2.5. We anticipate taking measurements of turbulent layers up to 15km in altitude with a resolution of approximately 1km. Our system will also be sensitive to ground layer atmospheric turbulence. Here we present details of the optical and mechanical design in addition to preliminary results.
Date of Conference: September 19-22, 2017
Track: Optical Systems