The distortion of the stars in those parts of the map is just an effect of the projection. The oval shapes near the top and bottom of the star maps are not galaxies. They are designed for spherical mapping in animation software. The maps are presented in plate carrée projections using either celestial (ICRF/J2000 geocentric right ascension and declination) or galactic coordinates. The constellation figures also come from the IAU, although they're not official. The constellation boundaries are those established by the International Astronomical Union in 1930. This set of star maps was created by plotting the position, brightness, and color of 1.7 billion stars from the Hipparcos-2, Tycho-2, and Gaia Data Release 2 star catalogs, with help from the Yale Bright Star Catalog, UCAC3, and the XHIP Hipparcos cross-reference.