AVAILABLE ALL-SKY DATA IN 1978 observation hours per month STATION JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC films (*) OULU 66 0 0 0 0 0 0 0 0 0 0 0 2 SODANKYLA 143 115 101 46 0 0 0 0 64 219 259 272 35 MUONIO 157 88 86 43 0 0 0 0 77 17 77 187 20 IVALO 146 47 90 39 0 0 0 6 26 57 128 95 17 KEVO 199 101 148 21 0 0 0 6 59 119 142 123 23 HANKASALMI 0 65 19 52 0 0 0 0 120 226 197 288 14 KILPISJARVI 0 0 266 58 0 0 0 0 139 121 140 205 25 KIRUNA 0 0 0 0 0 0 0 0 111 100 315 256 17 TROMSO 0 0 0 0 0 0 0 0 0 0 0 0 0 HORNSUND 0 0 0 0 0 0 0 0 0 0 0 0 0 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