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The duo will appear high in the southwestern sky after nightfall and will gradually slip down toward the horizon before setting around 9 p.m., local time. An encore will be visible the following ...
Stars slowly lose mass by the emission of a stellar wind from the photosphere. The star's magnetic field exerts a torque on the ejected matter, resulting in a steady transfer of angular momentum away from the star. Stars with a rate of rotation greater than 15 km/s also exhibit more rapid mass loss, and consequently a faster rate of rotation decay.
On Friday 24 January and Saturday 25 January, six planets will line up in the night sky, in an event that some astronomers refer to as a planetary parade. Mars, Jupiter, ...
Star trails captured during a total lunar eclipse. In astronomy, diurnal motion (from Latin diurnus 'daily', from Latin diēs 'day') is the apparent motion of celestial objects (e.g. the Sun and stars) around Earth, or more precisely around the two celestial poles, over the course of one day.
For this reason, to simplify the description of Earth's orientation in astronomy and geodesy, it was conventional to chart the positions of the stars in the sky according to right ascension and declination, which are based on a frame of reference that follows Earth's precession, and to keep track of Earth's rotation, through sidereal time ...
[citation needed] [dubious – discuss] In large cities, about 300 to 500 stars can be seen depending on the extent of light and air pollution. [citation needed] The farther north, the fewer are visible to the observer. [citation needed] The brightest star in the night sky is located in the southern celestial hemisphere and is larger than the Sun.
Sigma Octantis is the current southern pole star, whose counterpart is Polaris, the current North Star. To an observer in the southern hemisphere, Sigma Octantis appears almost motionless and all the other stars in the Southern sky appear to rotate around it. It is part of a small "half hexagon" shape.
A pole star is a visible star that is approximately aligned with the axis of rotation of an astronomical body; that is, a star whose apparent position is close to one of the celestial poles. On Earth, a pole star would lie directly overhead when viewed from the North or the South Pole.