Celestial-Equatorial (RA/Dec) Demonstrator
The Celestial Sphere
Star Position
RA: h
dec: °
you can also change the star's position by dragging it
Labels
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Celestial-Equatorial (RA/Dec) Demonstrator

This simulator shows the equatorial coordinate system projected onto the celestial sphere centered on Earth.

Right Ascension (RA) is measured eastward from the vernal equinox (0h circle) along the celestial equator, from 0h to 24h.

Declination (dec) is measured north (+) or south (−) of the celestial equator, from −90° to +90°.

Drag the sphere to rotate the view. Drag the star (✦) to reposition it. Use the sliders or type values directly.

The green lines are celestial great circles. The blue arc shows RA, the red arc shows declination.