AVAILABLE ALL-SKY DATA IN 1987 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 414 291 171 88 0 0 0 0 69 299 208 417 41 MUONIO 0 0 0 0 0 0 0 0 0 41 0 24 2 IVALO 0 0 0 0 0 0 0 0 0 0 0 0 0 KEVO 169 125 119 58 0 0 0 6 56 152 180 225 19 HANKASALMI 0 0 0 0 0 0 0 0 0 0 0 0 0 KILPISJARVI 394 198 196 78 0 0 0 41 221 166 276 388 50 KIRUNA 0 0 0 0 0 0 0 0 0 0 0 0 0 TROMSO 0 0 0 0 0 0 0 0 0 0 0 0 0 HORNSUND 43 71 0 0 0 0 0 0 0 0 0 129 4 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