TY JOUR TI INVESTIGATION OF LONG-TERM CHANGES IN THE LEVEL OF SKY ILLUMINATION AS AN ENVIRONMENTAL FACTOR KW -8 KW night sky illumination KW light pollution KW astronomical observations KW CrAO KW AMT-8 JO Russian Journal of Biological Physics and Chemisrty AU Nazarov, S.B. AU Rogova, O.V. AU Khalaimova, A.V. PY 2018 IS 3 PB Federal State Educational Institution of Higher Education Sevastopol State University