Right ascension, a celestial coordinate dating back to Hipparchus, measures the east-west position of celestial objects along the celestial equator, starting from the vernal equinox. Right ascension, ...

The equatorial coordinate system projects Earth's latitude and longitude onto the celestial sphere, using declination (angular distance from the celestial equator, measured in degrees) and right ...

Newly discovered fragments of 2,200-year-old star coordinates—once thought lost—reveal the incredible skill of the ancient astronomer Hipparchus. This colored version of a 19th-century engraving ...

Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria Research Institute It’s the time of the equinox or more specifically the spring equinox for us in the ...