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Sunrise on the Solstice



 
 
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  #1  
Old December 7th 18, 02:54 PM posted to sci.astro.amateur
Gerald Kelleher
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Default Sunrise on the Solstice

A myth has grown up around the notion that sunrise continues to occur later after the Solstice.

https://www.timeanddate.com/sun/irel...h=12&year=2018


Natural noon as opposed to clock noon is always symmetrical to sunrise and sunset so the value for daylight length divided by 2 and added to the time of sunrise should be the same from natural noon to sunset.

The total length of daylight is shortest on the December Solstice as it decreases up to then before growing longer after Dec 21st.

There is a problem however that few would spot and it is unfair on society - it gives sunrise to sunrise as exactly 24 hours despite the principle that sunrise to sunrise, noon to noon or sunset to sunset are not 24 hours -

"Here take notice, that the Sun or the Earth passeth the 12. Signes, or makes an entire revolution in the Ecliptick in 365 days, 5 hours 49 min. or there about, and that those days, reckon'd from noon to noon, are of different lenghts; as is known to all that are vers'd in Astronomy." Huygens

https://adcs.home.xs4all.nl/Huygens/06/kort-E.html


I have been fortunate enough to being inside the ancient neolithic monuments at sunrise on the Solstice and daylight still streams through the ancient passageway the same number of days either side of the Solstice before going dark for the rest of the year -

https://www.newgrange.com/winter_solstice.htm

A lot of cheating going on to impress a population which has been severely affected by the mangling of timekeeping and astronomy by a small group of people who exploited the natural intricacies which are part and parcel of astronomical reasoning - it is great if people can get away with it but diminishes astronomy nonetheless.

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  #2  
Old Yesterday, 09:41 AM posted to sci.astro.amateur
Gerald Kelleher
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Default Sunrise on the Solstice

Although the arrow is pointing in the wrong direction, it is approaching Polar noon at the South Pole and midnight at the North as those latitudes continue to turn in a small circle thereby creating a day/night cycle separate to daily rotation -

https://upload.wikimedia.org/wikiped...precession.svg

The pool of water around the North Pole will continue to become more and more frozen as the area remains opposite to the Sun for a number of months even when the maximum area in complete darkness starts to contract in a few weeks time.

It did strike me yesterday that even when a necessary adjustment was necessary to bring dates back in line with the orbital points that certain academics who considered themselves 'enlightened' refused to make the correction until over 150 years after the Church did. I understand that the same dreary mentality is alive and well today even when the same people moan about saving the planet and dire consequences.

The fact is that aside from daily rotation and all its effects, the entire surface of the planet turns parallel to the orbital plane so although Copernicus only framed it in terms of the North and South Poles, imaging range and power now affirms the entire surface of all planets do turn as a function of their orbital motions.

"The third is the motion in declination. For, the axis of the daily rotation is not parallel to the Grand Orb's axis, but is inclined [to it at an angle that intercepts] a portion of a circumference, in our time about 23 1/2°. Therefore, while the earth's center always remains in the plane of the ecliptic, that is, in the circumference of a circle of the Grand Orb, the earth's poles rotate, both of them describing small circles about centers [lying on a line that moves] parallel to the Grand Orb's axis." Copernicus, Commentariolus






 




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