Site monitoring at Mount Stromlo

The performance of large ground based optical telescopes greatly suffers from the turbulent atmosphere. However, the problems can be mitigated by using techniques such as adaptive optics. To optimally build and operate adaptive optics systems, as well as understand if they are working as designed, we need to understand the typical atmospheric conditions on the site where the telescope is built. Therefore, Advanced Instrumentation and Technology Centre is conducting a site characterization campaign at Mount Stromlo. 

Objectives

The aim of the project is to produce statistics of how atmosphere behaves above Mount Stromlo. We are interested in the strength of the turbulence, as well its evolution speed and altitude profile. This will help to design the systems that compensate the impacts of the turbulence.

Activities

We have designed a unique modification of an instrument typically used to characterise atmospheric turbulence: SCintillation Detection And Ranging (SCIDAR), which measures light from suitable sets of two stars. The instrument is installed on EOS 1.8 m telescope and operated intermittently during the campaign. In addition, we have started to prototype a SLODAR system that is similar to SCIDAR in many respect, but in principle is better suited to analyse a strong turbulence that is often encountered if the weather is not ideal.

Outcomes

Prototype instruments need to be assembled in laboratory. Commissioned instruments provides a large amount of raw data that needs to be calibrated and analysed. This will give us useful insight for how well Mount Stromlo suits for future the adaptive optics instruments for space-situational awareness and free-space optical communication.

Relevant publications

  • Korkiakoski, Visa, et al. "Site characterisation at Mount Stromlo: the first results." AO4ELT, 2017.

  • Korkiakoski, Visa, et al. "Single detector stereo-SCIDAR for Mount Stromlo: data analysis." Proc. SPIE, 2016. 

  • Grosse, Doris, et al. "Single detector stereo-SCIDAR for Mount Stromlo." Proc. SPIE, 2016.