AVAILABLE ALL-SKY DATA IN 1980 observation hours per month STATION JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC films (*) OULU 0 0 0 0 0 0 0 0 0 0 0 0 0 SODANKYLA 179 145 136 56 0 0 0 0 166 102 197 125 19 MUONIO 164 149 84 25 0 0 0 0 67 170 32 90 15 IVALO 0 0 0 0 0 0 0 0 0 0 0 0 0 KEVO 105 4 123 18 0 0 0 0 58 94 71 138 10 HANKASALMI 98 100 16 54 0 0 0 0 70 76 173 89 15 KILPISJARVI 190 185 65 12 0 0 0 0 100 106 221 215 24 KIRUNA 265 230 224 77 0 0 0 0 99 195 278 365 37 TROMSO 0 0 0 0 0 0 0 0 0 0 0 0 0 HORNSUND 0 0 0 0 0 0 0 0 0 46 113 110 15 ANDOYA 0 0 0 0 0 0 0 0 0 0 0 0 0 GEORG FORSTER 0 0 0 0 0 0 0 0 0 0 0 0 0 (*) analyzed films per year