Site survey for the Large Array Survey Telescope (LAST): an extensive research of seeing and meteorological conditions


  Shani Nachshon  ,  Avishay Gal Yam  ,  Sagi Ben Ami   
Weizmann Institute of Science

Weizmann institute of science is in progress of designing a state of the art observatory to host the Large Array Survey Telescope (LAST) in southern Israel. An integral part of the preparation is determining the best location for the observatory. This should be chosen carefully considering sky brightness and seeing conditions, the latter a measure of image quality degradation caused by atmospheric turbulence. Two sites are examined in southern Israel: Shidrit, ~20 km from Mizpe Ramon, and Yeelon near Neot Semadar. This study will undertake an extensive survey of the sites, obtaining short and long-term in-situ measurements of seeing and meteorological conditions using a seeing monitor and an automated weather station. We further attempt to identify correlations between seeing and meteorological data using machine learning algorithms. Our preliminary results show seeing medians of of 2.9±0.5 and 3.5±0.9 arcsec per night, with best values found during June-August with medians of 2.4±0.3 and 1.9±0.2 arcsec for Shidrit and Neot Semadar respectively. Correlation coefficients higher than p=0.5 were found for seeing with temperature, relative humidity, wind speed and wind gust, though the direction seemed to invert between nights. Additional data is yet required to achieve statistical significant conclusions.