Astronomers measure a star’s brightness using the apparent magnitude system, where lower values indicate brighter stars.

SiriusXM and Maxar Space Systems announced today that the SXM-9 satellite has completed in-orbit testing and is now fully ...

Greek astronomer Claudius Ptolemy, who lived in Egypt, built upon Babylonian knowledge in his geocentric model of the ...

A celestial event being hyped by some internet sites as an extremely rare planetary alignment has been oversold, astronomers are saying, but it should be a cool show if the sky is clear Saturday ...

Equally significant was the Egyptians' use of the 365-day solar calendar, which divided the year into three seasons of 120 ...

The Wolf Moon will reach its peak fullness at 5:27 p.m. Eastern Time on January 13. It will rise in the sky about an hour ...

In ancient Egypt, the new year began with the heliacal rising of Sirius, the brightest star ... introducing the Julian calendar. This solar-based system officially started the civil year on ...