Direct and expanded R frames of the galaxy M 51:
a) composition of 2 direct frames, the scale is 2.7"/pix;
b) composition of 4 frames with focal expander, the scale is 1.82"/pix;
c) the same as in (b) but under 1.82 times expanding in the process of the digital rebinig and adding of the frames, the scale is 1"/pix;
d) the same as in (c) but after 2D polynomial smoothing.