CREATE TABLE table_25597136_1 (date_first_lit VARCHAR(255), focal_plane_in_ft__m_ VARCHAR(255))
Focal plane in ft (m) is 43ft (13.1m) is the first date lit.
    
SQL: SELECT date_first_lit FROM table_25597136_1 WHERE focal_plane_in_ft__m_ = "43ft (13.1m)"