Animation showing the movement of Sagittarius across the night sky as seen by an observer at 35º South latitude. Only Sagittarius is shown in the animation; all other constellations have been omitted for clarity. The directions and altitudes shown refer to a star located on the ecliptic in central Sagittarius, indicated by a small yellow cross (+).
The constellation's direction and altitude (Alt) are shown at hourly intervals before Meridian Transit (-1 hour, -2 hours, etc) and after Meridian Transit (+1 hour, +2 hours, etc).
In the Southern hemisphere, the observer faces North to observe a zodiac constellation's meridian transit (as opposed to facing South in the Northern hemisphere). Constellations normally seen 'upright' (North up) in the Northern hemisphere appear inverted (South up) in the Southern hemisphere. Consequently, a Northern hemisphere observer visiting the Southern hemisphere will need to turn their familiar star atlas upside-down to match the view they see in the Southern hemisphere sky.
Because of Sagittarius' southerly declination (i.e. its angle South of the celestial equator) it remains above the horizon for a longer period of time in the Southern hemisphere than in the Northern hemisphere, covering a wider arc of the sky and transiting at a much higher altitude.
Scenery: Sydney Opera House and Harbour Bridge, New South Wales, Australia (latitude 33º.8 South) (modified screen capture from Microsoft's Flight Simulator 2004)
Copyright Martin J Powell Jul 2008