![]() ![]() Out here in central Colorado the Sun sets over the mountains, and it’s always magnificent. Or who knows, maybe I’ll still give it a shot. I’m so glad! Now what we need is for someone in Arizona or some such location to do this, where the weather is more likely to be clear. I’ve known this was true for a long time, but I’ve never actually seen it shown this way. The weather gets pretty bad, but you can still see enough to get a sense that the Sun moves most rapidly at the equinoctes and most slowly at the solstices, just as I said. It slows and stops again at the December solstice (note the snow on the rooftops!), then reverses, moving north again. You can then see it slow, stop at the June solstice, and then reverse direction, moving south (right). The Sun rises due east, then moves left (north) every morning at a rapid rate. The video starts at the vernal equinox in 2015, on March 21, and runs through to March 20, 2016. Follow Astro Navigation Demystified on WordPress.That’s great! Yes, it’s cloudy and rains a bit in Germany at sunrise, but you can still see the Sun’s motion.Stars For All Seasons Part 7 – Spring Stars in the Northern Hemisphere.The Importance Of Morning And Evening Star Sights.The Importance of Morning and Evening Star Sights – Part 2.The Purpose of Altitude and Azimuth Angle in Position Finding at Sea.The Retrograde and Prograde Motions of Mars and Jupiter.The Winter Solstice usually falls on 21 December but sometimes falls on 22 December.Īstro Navigation Demystified is available from and Amazon.uk Similarly, the Summer Solstice usually falls on 21 June but sometimes falls on 20 June. The Autumnal Equinox sometimes falls on 22 September and sometimes on 23 September. So, the Vernal Equinox sometimes falls on 20 March and sometimes on 21 March. However for the sake of convenience, the Gregorian calendar divides three years of the cycle into 365 days and the fourth (the leap year) into 366. The dates of the equinoxes and the solstices will vary slightly during the four-year cycle between leap years for the following reason: Each year is approximately 365.25 days in length. The latitude of the tropic of Cancer is currently drifting south at approximately 0.5’’ per year while the latitude of the tropic of Capricorn is drifting north at the same rate. The Winter Solstice (mid-winter in the northern hemisphere) occurs on about 21 December when the Sun’s declination is 23. The Summer Solstice (mid-summer in the northern hemisphere) occurs on about 21 June when the Sun’s declination reaches 23. This is because the apparent movement of the Sun seems to stop before it changes direction The word solstice is taken from ‘solstitium’, the latin for ‘sun stands still’. The times when the Sun reaches the limits of its path of declination are known as the solstices. The Vernal Equinox occurs on about the 21 March when the Sun crosses the celestial equator as it moves northwards from 23.5 o South, the southernmost limit of its declination. 5 o North, the northernmost limit of its declination. The Autumnal Equinox occurs on about the 22 September when the Sun crosses the celestial equator as it moves southwards from 23. Because the Sun is on the celestial equator at the equinoxes, its declination is of course 0 o. 12 hours) hence the term equinoxes (equal nights). At the equinoxes, at all places on Earth, the nights and days are of equal duration (i.e. The Sun crosses the celestial equator on two occasions during the course of a year and these occasions are known as the equinoxes. Sun reaches highest point in local sky on June solstice. True for Northern Hemisphere: At high latitudes, Sun never rises on December solstice. Not true anywhere on Earth: Sun reaches zenith (altitude 90 degrees) every day at noon. Declination can be summarized as the celestial equivalent of Latitude since it is the angular distance of a celestial body North or South of the Celestial Equator. True every where on Earth: Sun rises due east and sets due west on March equinox. 5 o South and back again during the course of a year. The declination of the Sun changes from 23.5 o North to 23. The Declination of a celestial body is its angular distance North or South of the Celestial Equator. ![]()
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