The Ecliptic Seasons change, Stars change • the annual path that the sun traces in the sky. • the projection of the plane of the Earth’s orbit Apparent direction of onto the celestial sphere. motion of the sun across Gemini • the constellations which the ecliptic the celestial dome Towards the traverses are called the zodiac. North sun at noon on June 20 On June 20 summer Equator begins in the northern North Celestial Sphere Direction of view at hemisphere. The north midnight on Dec. 20 pole reaches its maximum Ecliptic Position of tilt towards the sun. the Earth Orion North Sun on Dec. 20 Position of the Earth Scorpius on June 20 Celestial Sphere Sirius North On Dec. 20th Winter begins Direction of view at in the northern midnight on June 20 Equator hemisphere. Direction The north pole of view at reaches its noon on Towards the maximum tilt June 20 sun at noon Sagittarius Sagittarius from the sun. on Dec. 20 Gemini Ecliptic Consider that... Sunlight conceals the stars during Sun on • the sun is higher at noon in the day. Direction that June 20 June than in December, the sun • the sun is slightly farther Direction that moves along from the Earth in June than in the sun Constellation the ecliptic December, moves along Scorpius Sun on • the stars that are in the the ecliptic midnight December sky are Dec. 20 Constellation the same stars in the noon Orion June sky, and vice versa, The star Sirius • the ecliptic is high at Constellation midnight in December and at Sagittarius noon in June, South • and the ecliptic is low at South View to the south noon in December and at View to the south on on June 20 at noon. midnight in June. December 20 at noon. Gemini Consider that... Of course, there are many other stars Ecliptic visible, some dim, some bright. • the sun always lies directly on the ecliptic line, moving two Direction that of its own apparent diameters Direction that the sun moves along to the east each day, the sun Constellation the ecliptic • it takes the sun 365 days to moves along Scorpius the ecliptic complete one circuit around Sirius, the brightest the ecliptic, and star in the night sky Constellation • the moon and the planets lie Orion either on or near the ecliptic. Constellation Of course, there are many other stars Sagittarius visible, some dim, some bright. South South View to the south on View to the south on Astronomical League June 20 at midnight. December 20 at midnight. www.astroleague.org Design by John Jardine Goss .