Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 March 30
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Beijing Ancient Observatory
Credit & Copyright: Judy Tobin

Explanation: Did observatories exist before telescopes? One example that still stands today is the Beijing Ancient Observatory in China. Starting in the 1400s astronomers erected large instruments here to enable them to measure star and planet positions with increasing accuracy. Pre-telescopic observatories throughout the world date back to before recorded history, providing measurements that helped to determine when to plant crops, how to navigate ships, and when religious ceremonies should occur. It is interesting to compare the above picture to one taken in 1895.

Tomorrow's picture: Plumes Toward Mars


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