Drawing of Observatory

Astronomer's weather forecast showing cloud cover, transparency, steadiness, and darkness.

Click on any of the "hour squares" in the Clear Sky Clock above to see an explanation of all its terms and symbols.


The U.S. Naval Observatory clock below does not run in Microsoft Internet Explorer. It does run for a maximum of 30 seconds in other browsers such as Netscape Navigator and Mozilla Firefox. "Refresh" or "Reload" your browser (usually by pressing your F5 key) to re-activate the clock for a few seconds.

USNO Clock

For a continuously operating real-time clock showing areas of the Earth in daylight and darkness visible in all browsers click


Sky & Telescope Sights for the week selected by Sky & Tel magazine.
Heavens-Above (GSOC) Artificial satellite visibility predictions.
What's Up NASA JPL Video
A two-minute video guide tells you where to look and what to see in the sky each month. This service is provided by JPL Education Gateway.
SpaceWeather.com Science news and information about the Sun-Earth environment. Includes daily images and reports of solar activity.
Space.com Current Moon phase and planet info.
The Weather Channel Weather forecast for Cranford area.
Sperry Observatory Light Pollution Map Attilla Danko of cleardarksky.com presents a light pollution map for Sperry Observatory.
Maintained by Ray Shapp
Page last updated 01/03/2011