Perspective of the Moon from the Northern and Southern Hemispheres

September 13, 2011

2 Moons 2
: Mario Freitas
Summary Authors: Mario Freitas; Jim Foster

As a consequence of our planet being ball-shaped, observers in the Southern Hemisphere see celestial bodies and constellations upside-down when compared to how they appear in the Northern Hemisphere. The two photos above, depicting the waxing gibbous Moon rising over the eastern horizon, were taken 28 hours apart, using the same camera, before and after an international flight from Curitiba, Brazil to Paris, France. Although the lunar disk displays almost the same phase and the same elevation in both pictures, it seems to have tumbled in the sky. This of course is due to the change in the observer’s horizontal plane. Note the inclination of the Moon’s terminator, with reference to the wires and trees in the first picture, and the vertical chimneys in the second.

The lunar phase is a result of the relative locations of the Moon, Earth and Sun and doesn’t depend on where on the Earth’s surface you’re looking. But how the Moon is oriented in the sky depends on the latitude (and hemisphere) of the observer. However, the size of the Moon, regardless of phase, is the same as viewed everywhere on Earth. Photos taken on July 9/10, 2011.

Photo Details: Both photos - Camera: Panasonic: DMC-LX5; Focal Length: 19.2mm (35mm equivalent: 171mm); Aperture: f/4.0; Exposure Time: 0.0080 s (1/125); ISO equiv: 80.