Na-light flare observations: McMath 13043-July 1974

We extract a temporal sequence of the 1355 UT 4 July, 1974 event from monochromatic filtergrams in Na light obtained in Rome on the McMath region No. 13043-July 1974. It is, to our knowledge, the first temporal sequence of a flare seen through a narrow-band filter (80 mÅ) in the Na-D lines. Due to the properties of Na filtergrams we could also derive quite easily the exact relative position among sunspots, magnetic fields and flare-knots. The last result is indeed a very useful tool when studying an active region. For the McMath No. 13043 we were able to infer some interesting remarks about the magnetic pattern at the flaring site.