![]() ![]() Select here for animations of the Sun's motion at two different locations Rotation arc around you, and therefore you have 12 hours of daylight and 12 hours Remember, that everybody anywhere on the Earth sees 1/2 of the celestialĮquator so at the equinox, when the Sun is on the equator, you see 1/2 of its Observers in the southern hemisphere, the situation is reversed. North of the celestial equator takes more than 12 hours between risingĪnd setting because most of its rotation arc is above the horizon. Of the celestial equator takes less than 12 hours between rise and set,īecause most of its rotation arc around you is hidden below the horizon. So for northern observers, anything south Every celestial object's diurnal (daily) motion is Since the sky appears to rotateĪround you in 24 hours, anything on the celestial equator takes 12 hours to goįrom exact east to exact west. Will see 1/2 of the celestial equator's arc. No matter where you are on the Earth, you Path it follows depends on the date and the observer's latitude. South of the celestial equator, and set in the southwest. The Sun will rise in the southeast, follow a short, low arc When the Sun isīelow the celestial equator during the seasons of autumn and winter, you will have The day of the year and the latitude of the observer. It rises or sets and how long the Sun is above the horizon depends on The celestial equator, and set in the northwest. The Sun will rise in the northeast, follow a long, high arc north of Of spring and summer, you will have more than 12 hours of daylight. When the Sun is above the celestial equator during the seasons On those two days of the year, the Sun will rise in theĮxact east direction, follow an arc right along the celestial equator Marks the beginning of the three-month season of spring on our calendar and theĭay of the autumn equinox marks the beginning of the season of autumn (hence, the name ``equinox'' for ``equal night''). When the Sun is on the celestial equator at the equinoxes,Įverybody on the Earth experiences 12 hours of daylight and 12 hours of night for those The celestial equator moving northward at the vernal equinox around March 21Īnd crosses the celestial equator moving southward at the autumnal equinoxĪround September 22. Two points: the vernal (spring) equinox and autumnal (fall) equinox. The ecliptic and celestial equator intersect at The fast motion of the rising and setting Sun during a day. Be sure to keep distinct in your mind the differenceīetween the slow drift of the Sun along the ecliptic during the year and This circular path is tilted 23.5Ĭelestial equator because the Earth's rotation axis is tilted by 23.5 degrees The apparent yearly path of the Sun through the stars is called theĮcliptic. Of the Earth around the Sun in its orbit. This drift eastward is now known to be caused by the motion It makes oneįull circuit of 360 degrees in 365.24 days (very close to 1 degree or twice itsĭiameter per day). Respect to the stars (or lag behind the stars) over a year's time. Near the poles, so the solar day is measured from ``noon to noon''. ![]() Also, the time of the sunriseĪnd sunset changes throughout the year, very dramatically so if you live Horizon at exactly East and exactly West). Throughout the year (remember though, the celestial equator always intercepts the ![]() The exact position on the horizon of the rising and setting Sun varies The ``noon position'' is when the Sun is on the meridian Reaches maximum height when it crosses the meridian at local noon,ĭirection and it takes the Sun on average 24 hours to go from noon position to Every day the Sun rises in an easterly direction, Now that you have your bearings, let's take a look at the position and motion See my copyright notice for fair use practices. Video lecture for this chapter This material (including images) is copyrighted!. Astronomy Without a Telescope Motion of Our Star the Sun Chapter index in this window ![]()
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