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- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_2e_(OpenStax)/02%3A_Observing_the_Sky_-_The_Birth_of_Astronomy/2.02%3A_The_Sky_AboveThe direct evidence of our senses supports a geocentric perspective, with the celestial sphere pivoting on the celestial poles and rotating about a stationary Earth. We see only half of this sphere at...The direct evidence of our senses supports a geocentric perspective, with the celestial sphere pivoting on the celestial poles and rotating about a stationary Earth. We see only half of this sphere at one time, limited by the horizon; the point directly overhead is our zenith. The Sun’s annual path on the celestial sphere is the ecliptic—a line that runs through the center of the zodiac, which is the 18-degree-wide strip of the sky within which we always find the Moon and planets.
- https://phys.libretexts.org/Courses/Prince_Georges_Community_College/General_Physics_I%3A_Classical_Mechanics/57%3A__Celestial_Mechanics/57.03%3A_Orbit_Reference_FramesIn the equatorial reference frame, the reference plane is the plane of the Earth's equator, and the reference direction is the direction of the vernal equinox. the plane of the Earth's orbit around th...In the equatorial reference frame, the reference plane is the plane of the Earth's equator, and the reference direction is the direction of the vernal equinox. the plane of the Earth's orbit around the Sun), and the reference direction is again in the direction of the vernal equinox. The plane of the equator and the plane of the ecliptic intersect along a line, and the direction of the vernal equinox lies along that line of intersection.
- https://phys.libretexts.org/Courses/Prince_Georges_Community_College/Introduction_to_Astronomy_(2025)/01%3A_An_Introduction_to_Astronomy/1.03%3A_Observing_the_Sky_-_The_Birth_of_Astronomy/1.3.02%3A_The_Sky_AboveThe direct evidence of our senses supports a geocentric perspective, with the celestial sphere pivoting on the celestial poles and rotating about a stationary Earth. We see only half of this sphere at...The direct evidence of our senses supports a geocentric perspective, with the celestial sphere pivoting on the celestial poles and rotating about a stationary Earth. We see only half of this sphere at one time, limited by the horizon; the point directly overhead is our zenith. The Sun’s annual path on the celestial sphere is the ecliptic—a line that runs through the center of the zodiac, which is the 18-degree-wide strip of the sky within which we always find the Moon and planets.
- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Astronomy_1e_(OpenStax)/02%3A_Observing_the_Sky_-_The_Birth_of_Astronomy/2.01%3A_The_Sky_AboveThe direct evidence of our senses supports a geocentric perspective, with the celestial sphere pivoting on the celestial poles and rotating about a stationary Earth. We see only half of this sphere at...The direct evidence of our senses supports a geocentric perspective, with the celestial sphere pivoting on the celestial poles and rotating about a stationary Earth. We see only half of this sphere at one time, limited by the horizon; the point directly overhead is our zenith. The Sun’s annual path on the celestial sphere is the ecliptic—a line that runs through the center of the zodiac, which is the 18-degree-wide strip of the sky within which we always find the Moon and planets.
- https://phys.libretexts.org/Courses/Grossmont_College/ASTR_110%3A_Astronomy_(Fitzgerald)/01%3A_Earth_Cycles_Moon_Cycles_and_Sky_Information/1.05%3A_The_Sky_AboveThe direct evidence of our senses supports a geocentric perspective, with the celestial sphere pivoting on the celestial poles and rotating about a stationary Earth. We see only half of this sphere at...The direct evidence of our senses supports a geocentric perspective, with the celestial sphere pivoting on the celestial poles and rotating about a stationary Earth. We see only half of this sphere at one time, limited by the horizon; the point directly overhead is our zenith. The Sun’s annual path on the celestial sphere is the ecliptic—a line that runs through the center of the zodiac, which is the 18-degree-wide strip of the sky within which we always find the Moon and planets.
- https://phys.libretexts.org/Bookshelves/Astronomy__Cosmology/Introduction_to_Astronomy_(Lumen)/03%3A_Motions_of_the_Moon_Sun_and_Stars/3.03%3A_The_Sun_and_the_MoonThis page discusses the movement of the Sun, Moon, and planets along the Ecliptic on the Celestial Sphere and introduces the Zodiac, consisting of 12 constellations plus one additional. It explains th...This page discusses the movement of the Sun, Moon, and planets along the Ecliptic on the Celestial Sphere and introduces the Zodiac, consisting of 12 constellations plus one additional. It explains that astronomers measure sizes and distances in angular measurements, noting that the Sun and Moon appear to span approximately ½ degree or 30 arcminutes from Earth's view, despite their actual sizes being different.