Based on a true story about Roberto "Beto" Bubas, a ranger in Chubut, Patagonia Argentina.
The name of the white horse is the same as a bright star (a blue supergiant), Rigel, in the constellation of Orion (also known as Beta Orionis). It is on the left of the Orion's Belt, if Sirius is on the top, and Betelgeuse is on the right.
Beto talks about Sirius (also known as Alpha Canis Majoris, or Alpha CMa), the brightest star in the sky (in both hemispheres). It is the fourth brightest object in the night sky, after the Moon, Venus, and Jupiter.
Beto talks about Southern Cross (also known as Crux), the smallest of the eighty-eight constellations, made up of 49 stars. The four main stars are Acrux, Mimosa, Gacrux, and Imai (these form the cross). At some point in the past (untill 16th century) the Greeks considered it part of Centaurus.