|
Credit & Copyright: Osvaldo Castillo
Explanation:
At the latitude of ESO's
Paranal Observatory
in Chile, about 25 degrees south,
Earth's
rotation moves the planet's surface eastward at over 1,500 kilometers per hour.
And while that's faster than the
speed of sound
at sea level, the motion is
imperceptible.
Still, that motion can be revealed in the
apparent rotation of the
night sky by
photographing
star trails.
This star trail image was composed from a digital stack of 300
consecutive 25-second exposures made with a camera
fixed to a tripod to trace the star trail arcs.
The graceful arcs are concentric and centered at the south
celestial pole,
the southern hemisphere extension of Earth's axis of rotation into space.
One of the observatory's operating 1.8 meter auxiliary telescopes,
AT 3,
appears beneath the south celestial pole,
faintly illuminated in the foreground of this
well-planned scene from a rotating planet.
APOD's main NASA site is
moving:
From apod.nasa.gov to
science.nasa.gov/apod
|
January February March April May June July August |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||
NASA Web Site Statements, Warnings, and Disclaimers
NASA Official: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& Michigan Tech. U.
Based on Astronomy Picture
Of the Day