Astronomy

Why is sunset on 21st of June not the latest?

Why is sunset on 21st of June not the latest?


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Why is the sunset not the latest on 21 June, but only on 27 June. Purely geometrically regarding the orbit of the two celestial bodies this should not be like this?

Is there somewhere a good source, that explains this situation ?


It's explained in this Wikipedia article. Basically, the length of a day is defined by both the Earth's rotation itself and Earth orbiting around the sun. Because the Earth's orbit around the Sun isn't a circle but an ellipse (making it moving faster when it's closer to the Sun), and the Earth rotates in a plane different than it orbits the Sun, an apparent solar day isn't always 24 hours; in June, it's slightly longer. That means every day, "noon" (the time of day when the Sun is at its highest point) happens 'later' (compared to the time on your watch), so sunset (and sunrise) are also later. The first few days after June 21st, this effect is more significant than the effect of the Sun moving south (causing the day* to become shorter and the sunrise falling earlier). The same effect causes the earliest sunrise (in your location) to be on June 15th, so before the solstice.

*: day as in day vs. night, the period between sunrise and sunset, so not 24 hours


Why is the sunset not the latest on 21 June, but only on 27 June?

When the latest sunset occurs depends very much on latitude. For people who live in the far north (e.g., Anchorage, Alaska or Reykjavik, Iceland), the latest sunset occurs on the day of or a few days after the solstice. For people who live just north of the equator, the latest sunset occurs in late July.

The reason the latest sunset occurs in late July just north of the equator has nothing to do with the change in the time from sunrise to sunset; there is very little variation in the portion of a day that is sunlit near the equator. The reason the latest sunset is in late July is instead because that is when solar noon is at its latest. Solar noon occurs later and later in the day in the weeks preceding late July, but then it reverses direction. There are four extrema of the timing of solar noon over the course of a year. Late July represents one of those four extrema.

The time at which solar noon occurs varies over the course of a year. This variation is a consequence of the Earth's axial tilt and the eccentricity of its orbit. Mathematically, this is described by the equation of time, depicted in the two graphs below. The first shows the cumulative effect; this is the "equation of time." The second graph shows how much local noon changes on a day-per-day basis. Negative values such as in mid May to late July indicate when solar noon occurs later than it did on the previous day.

The length of time that a given place on the Earth north of the equator is sunlit decreases in the days after the solstice, with how much depending on latitude. Solar noon occurs later and later in the days after the solstice, and this change is the same for every location where the Sun is visible. This creates a latitudinal tension regarding when the latest sunset occurs. In far northern latitudes, the rapidly decreasing length of sunlight hours after the solstice quickly overcomes the slowly changing time at which solar noon occurs. Closer to the equator, the small seasonal changes in daylight make the latest solar noon mark the day with the latest sunset. When the latest sunset occurs is somewhere between these two extremes for intermediate northern latitudes. For your locale, the latest sunset was on June 27. Where I live, it occurred a few days later than that.


Northernmost sunset on June solstice

The path of the sun across our sky – from about noon to sunset – on 3 different days of the year, an equinox and the summer and winter solstices. The June solstice is the Northern Hemisphere’s summer solstice. Notice the northernmost sunset on this day. Marcella Giulia Pace made these observations from Gatto Corvino village, Sicily, Italy.

Northern Hemisphere summer

For us in the Northern Hemisphere, the June solstice signals the beginning of summer. For the Southern Hemisphere, winter starts at this solstice. The solstice is a whole-Earth event. It happens at the same instant for all of us, everywhere on Earth, but our clocks differ by time zone.

This 2021 June solstice happens on Monday, June 21, at 03:32 UTC. Translate UTC to your time. In North America and U.S. time zones, that’s June 21 at 12:32 a.m. Atlantic Daylight Time. But it’s on June 20 at 11:32 p.m. EDT, 10:32 p.m. CDT and so on, all the way to and 5:32 p.m. Hawaiian-Aleutian Standard Time.

The June solstice marks the year’s northernmost sunset and sunrise. It brings the year’s longest period of daylight to the Northern Hemisphere (least daylight in the Southern Hemisphere). North of the Arctic Circle, the sun neither rises nor sets but stays above the horizon continuously, around the clock.

In the Northern Hemisphere, noontime shadows are shortest at this solstice. It’s the year’s highest sun, as seen from the Tropic of Cancer and all places north.

Day and night sides of Earth at the instant of the June solstice (June 21 at 03:32 UTC). Map via Fourmilab.

Southern Hemisphere winter

Earth’s orbit around the sun – and tilt on its axis – have brought us to a place in space where our world’s Northern Hemisphere has its time of greatest daylight: its longest day and shortest night. Meanwhile, the June solstice and northernmost sun brings the shortest day and longest night south of the equator.

This solstice marks the beginning of Southern Hemisphere winter.

It marks the lowest sun and longest noontime shadow for those on the southern part of Earth’s globe.

South of the Antarctic circle, the sun neither rises nor sets but stays beneath the horizon for 24 hours.

View at EarthSky Community Photos. | Sunrise between a June and December solstice. If you are standing facing east, the sun – from day to day, and week to week – moves progressively to the right (south) between these 2 solstices. Rupesh Sangoi captured separate images of the sunrise, showing the sun’s movement along the horizon between a June and December solstice. He wrote: “Did this for over a year, at sunrise.” Glorious composite, Rupesh! Thank you.

Northernmost sunset, but not latest sunset

The sun sets farthest north on the day of the solstice, bringing the longest day for the Northern Hemisphere. But this summer solstice doesn’t bring the latest sunset. And it doesn’t bring the earliest sunrise. The exact dates vary with latitude, but the sequence is always the same: earliest sunrise before the summer solstice, longest day on the summer solstice, latest sunset after the summer solstice.

For the Southern Hemisphere, where it’s winter now, the latest sunrise – and earliest sunrise – don’t come on the day of the solstice either. Again, the exact dates vary with latitude. But the sequence is always the same: earliest sunset before the winter solstice, shortest day on the winter solstice, latest sunrise after the winter solstice.

Each solstice marks a turning of the year.

Even as this northern summer begins with the solstice, throughout the world the solstice also represents a “turning” of the year.

To many cultures, the solstice can mean a limit or a culmination of something. From around the world, the sun is now setting and rising as far north as it ever does. The solstice marks when the sun reaches its northernmost point for the year.

After the June solstice, the sun will begin its subtle shift southward on the sky’s dome again. Thus even in summer’s beginning, we find the seeds of summer’s end.

View larger. | Nikolaos Pantazis wrote: “Every year, on the days around summer solstice, the setting sun aligns with that rock, near the village of Platanos, Peloponnese, Greece.” At very northerly latitudes now, the sun is up all night. Here is the sun at 3 a.m. as seen near a June solstice by EarthSky Facebook friend Birgit Boden in northern Sweden.

Bottom line: Some quick info that’ll help you connect with nature at the June solstice 2021!


Earliest Sunset a Few Days Before

If you look at the sunrise and sunset times for any city in the Northern Hemisphere around the December Solstice, you will notice that the earliest sunset occurs a few days before the solstice and the latest sunrise happens a few days after the solstice.

This is also true for locations in the Southern Hemisphere. There, the year's earliest sunset happens a few days before, and the year's latest sunrise occurs a few days after the winter solstice in June.


Even though most people consider June 21 as the date of the June solstice, it can happen anytime between June 20 and June 22. June 22 solstices are rare - the last June 22 solstice in UTC time took place in 1975 and there won't be another one until 2203.

The Maypole is a symbol of Midsummer celebrations in Sweden.

. depending on who you ask. Astronomers and scientists use the date of the June solstice to mark the beginning of summer in the Northern Hemisphere and winter in the Southern Hemisphere. For meteorologists, on the other hand, summer began almost three weeks ago, on June 1.

In many Northern Hemisphere cultures, the day is traditionally considered to be the mid-point of the summer season. Midsummer celebrations on or around the Northern summer solstice are common in many European countries.


No, the Maya did not predict the end of the world on 21 June 2020

Oh, ridiculous and utterly wrong conspiracy doomsday theories. Will you ever die?

Probably not. Even ones long dead rise, zombie-like, to eat people's brains.

More Bad Astronomy

So it's no surprise that the newest one is, paradoxically, an old one. The claim is this: The Maya calendar predicts the end of the world, you see, and due to an incorrect calendar conversion it wasn't on 21 December, 2012, as originally thought, but actually on 21 June, 2020. This weekend.

First off, the Maya never predicted the end of the world. That whole 2012 stuff was wrong from the get-go. The Maya calendar, it was said by doomsday mongers, ended on 21 December 2012, and the Maya believed the world would end on that date.

You can’t make this up. Oh wait, they did: I saw this magazine in late 2012. Credit: Phil Plait

Except their calendar didn't end then. They had units of time they counted, just as we do. They didn't use weeks and months and years, but it's the same idea. It turns out that on 21 December 2012 one of their big units rolled over, similar to our date of 1999 turning into 2000. So it's like a new decade or century, that's all. There's some interpretation that they celebrated such things (as we do at midnight 31 December every year), but nothing that indicates they thought the world would physically end.

And what if they did? Lots of cultures have end-of-the-world stories, and in the history of humanity not a single one has ever been right. So why think this one will be?

I predicted at the time that we hadn't seen the end of this conspiracy theory, and of course I was right.

This time, various "news" venues are repeating a story that scholars got the date wrong, and the actual date is next week, on 21 June. They say that a scientist, Paolo Tagaloguin, tweeted about this. In these tweets (since deleted, they claim), Tagaloguin says:

Following the Julian Calendar, we are technically in 2012… The number of days lost in a year due to the shift into Gregorian Calendar is 11 days… For 268 years using the Gregorian Calendar (1752-2020) times 11 days = 2,948 days. 2,948 days / 365 days (per year) = 8 years.

Here's the thing: This is wrong. The Gregorian calendar does not lose 11 days per year! Basically, the Julian calendar, which was widely used a long time ago, didn't account for leap years very well, so hundreds of years ago countries started switching to the Gregorian calendar, which does a better job (though it's a little complicated). When they did, the calendar had to jump forward a bunch of days to compensate for days missed— usually about 10 or 11 days — but it was only done once. Not every year. So the claim that somehow 8 years have been skipped is wrong.

Second, that doesn't matter anyway, because the 21 December 2012 date was converted from the Maya calendar to the Gregorian one in the first place. So there's no reason to even bring the Julian calendar into this. It doesn't make sense.

Self-explanatory. Credit: Phil Plait

I looked up the scientist quoted in these articles, and there is no such Twitter account I could find either it never existed or it was deleted. There are some hits for that name, but nothing I can find that relates to the Maya. Perhaps there were tweets about this from this person, but were deleted when they realized they had screwed up … ?

Also, the tabloid articles all seem to link to each other, making it difficult to track down primary info. Some quote the UK tabloid the Daily Mirror, but the links never work and a search on their site yields no results for Paolo Tagaloguin. I searched on "maya calendar june 21" and got a result, but clicking the link gives a "no such page" error.

So there you go. Nonsense built on nonsense is still, well, nonsense. The Maya never predicted the end of the world, there's no physical basis for it, and, tellingly, the new claims are just wrong.

I'll note it irks me greatly that not one of these venues bothered to look up what the Julian and Gregorian calendars mean, or ask someone who might know. But then, they're promulgating long-debunked conspiracy theory claptrappery, so perhaps fact-checking is discouraged.

I mean, come on. If you're worried about the end of the world, then <waves vaguely in every direction>. There's no need to make up stuff when there's plenty to worry about right now that's real.


Why Is It Still Light After Sunset?

Even though the sun goes beneath the horizon, there is still light before it gets ideal for stargazing.

And this is because of the spherical shape of the Earth and the Sun’s distance of around 93 million miles away from the Earth.

So, even when the sun is beneath the horizon, the sunshine is still present in the atmosphere present on the surface of the earth.

This phenomenon is possible as the sunlight happens to hit the gas molecules (for example nitrogen and oxygen) present in the atmosphere.

The gas molecule is responsible for the bouncing effect of the sunlight which is then scattered.

The scattered light happens to hit of eyes making us see light in a lit-up sky even if the sun has set.

This phenomenon is the reason why twilight has three different phases.

And this is also the reason why we still see a bit of light even after the sunset.

All of the atmosphere that is there above your head will be still lit by the sun-rays at sunset.

However, the amount of light will become less rather rapidly during civil twilight.

When the sun reaches 6-degree beneath the horizon, the atmosphere that is there above your head will not be lit now as it was before.

Only a third of the atmosphere will still be lit by sun-rays giving the sky a dark blue shade.

This is why during nautical twilight the sky gets that blue shade.

Now, after this phase i.e. during the beginning of astronomical twilight, the highest layers of the atmosphere present at the horizon will only get the light.

Gradually when the sun is 18-degree below the horizon (end of astronomical twilight), nighttime takes over as at this point the whole atmosphere is not lit at all.


Solstice tale of two cities

Simulation of the line of sunrise as it strikes the U.S. eastern seaboard around the December solstice, via the U.S. Naval Observatory.

Around the time of the December solstice, the sun rises at the same time for both New York City and St. Augustine, Florida. On December 21, 2020, the sun rises at 7:16 a.m. Eastern Standard Time (EST). Look above at the simulated view of Earth as the sun is rising over the Atlantic seaboard of the United States around the time of the December winter solstice. Note that the terminator – the sunrise line – pretty much aligns with the U. S. East Coast, providing a similar sunrise time for coastal dwellers.

And yet, at this solstice, St. Augustine has about an hour more daylight than New York City. Although the sunrise occurs at the same time for both cities, the sunset happens about an hour later in St. Augustine. (See the sunrise/solar noon/sunset table below.)

Sunrise/solar noon/sunset times on December 21, 2020

City Sunrise Solar Noon Sunset
New York 7:16 a.m. 11:54 a.m. 4:29 p.m.
St. Augustine 7:16 a.m. 12:23 p.m. 5:30 p.m.

St. Augustine lodges about 7.5 degrees of longitude to the west of New York City. And our planet takes about 30 minutes to rotate this 7.5 degrees. Therefore, on any day of the year, the sun reaches its noontime position some 30 minutes later in St. Augustine than it does in New York City. For instance, on December 21, 2019, the noonday sun reaches its high point for the day at 11:54 a.m. EST in New York City. In St. Augustine, solar noon comes nearly 30 minutes later, at 12:23 p.m. EST.

St. Augustine resides appreciably south of New York City, so St. Augustine’s morning daylight (from sunrise to solar noon) lasts about 30 minutes longer than it does in New York City on the first day of winter. Thus, the longer period of daylight in St. Augustine cancels out the earlier noontime appearance of the sun in New York City, to give both localities the same sunrise time on the day of the December solstice.

Although New York, New York, and St. Augustine, Florida, both reside in the U.S. Eastern time zone, the noonday sun comes 30 minutes later to St. Augustine because it resides 7.5 degrees of longitude to the west of New York City.

Enter the equinoxes

Some three – and nine – months after the December solstice, St. Augustine and New York City receive the same amount of daylight on the days of the March and September equinoxes. On the equinoxes, noontime as well as sunrise and sunset come about 30 minutes later in St. Augustine than they do in New York City. The simulated view of Earth below shows the terminator – the sunrise line – running due north and south on the equinox. Neither the sunrise terminator nor sunset terminator comes anywhere close to aligning with the U.S. East Coast at either equinox.

Sunrise/solar noon/sunset times on March 20, 2021

City Sunrise Solar Noon Sunset
New York 6:58 a.m. 1:03 p.m. 7:09 p.m.
St. Augustine 7:28 a.m. 1:32 p.m. 7:37 p.m.

The terminator – sunrise line – runs due north and south on the equinoxes. The sunset line, though not shown, also runs north and south. Image via Earth and Moon Viewer.

Sunrise/solar noon/sunset times on September 22, 2021

City Sunrise Solar Noon Sunset
New York 6:44 a.m. 12:49 p.m. 6:54 p.m.
St. Augustine 7:14 a.m. 1:18 p.m. 7:22 p.m.

Enter the June solstice

Six months after the December solstice, it’s the June summer solstice for the Northern Hemisphere, coming yearly on or near June 21. Now, the situation is reversed from the December solstice, with New York City receiving about an hour more daylight.

Because New York City lies appreciably north of St. Augustine, New York City’s afternoon daylight (from solar noon to sunset) lasts some 30 minutes longer than in St. Augustine on the day of the June summer solstice. Thus, the extra daylight in New York City cancels out the later noontime in St. Augustine, to give both localities the same sunset time on the June solstice. (See sunrise/solar noon/sunset table below.)

The terminator – line of sunset – nearly parallels the Atlantic seaboard on the day of the June solstice.

Look above at the simulated view of Earth as the sun is setting over the Eastern seaboard of the United States on the day of the summer solstice. Note that the terminator – the sunset line – pretty much coincides with the East Coast, giving a similar sunset time for residents along the Atlantic seaboard.

From sunrise to sunset on the day of the June solstice, New York City residents enjoy about an hour more daylight than those in St. Augustine. Although the sunset occurs at about the same time for both cities, the sunrise happens an hour earlier in New York City on the day of the summer solstice.

Sunrise/solar noon/sunset times on June 20, 2021

City Sunrise Solar Noon Sunset
New York 5:25 a.m. 12:58 p.m. 8:30 p.m.
St. Augustine 6:25 a.m. 1:27 p.m. 8:29 p.m.

Bottom Line: On the day of the December winter solstice, the sun rises at the same time in both St. Augustine, Florida, and New York City, New York, but St. Augustine enjoys an hour more daylight. Six months later, on the day of the June solstice, it’s the sunset that happens at the same time in both places, but with New York City enjoying the extra hour of daylight.


On tap for June: UFO report, Jupiter and the summer solstice | The Sky Guy

Ken Kopczynski (Photo: Tallahassee Democrat files)

Are aliens visiting Earth?

According to some US fighter pilots and former government officials, they may be. In a recent "60 Minutes" segment, the former director of the defense department's Advanced Aerospace Threat Identification Program said that "unidentified aerial phenomena" in US airspace is of serious concern.

The director of National Intelligence and the Secretary of Defense are expected to present an unclassified report to Congress on this subject around June 1.

Here are some problems I see with the ability of aliens to travel the vast distances in space. It takes light traveling at 186,000 miles per second 4.5 years to reach the closest star to our solar system.

Currently it would take thousands of years to travel to the same star at speeds humans have attained.

So, Sky Guy, the aliens are so advanced that they can travel faster than light. The problem here is according to relativity, as an object approaches the speed of light it gains infinite mass. The more mass you gain the more energy required to push a vehicle through space.

How do you engineer materials capable of not being torn apart by stresses? What if you hit a small rock traveling near the speed of light? Not pretty.

Morning sky: Jupiter and Saturn continue to rule the morning sky. In early June Saturn rises around 1 a.m. followed by Jupiter, the brighter of the two, around 2 a.m. By the end of the month Saturn will rise around 11 p.m. and Jupiter at midnight. Mercury joins the two gas giants low in the east by the end of June.

Evening sky: Venus dominates the western sky though it will be low at the beginning of the month but very quickly catches up to Mars by the end of June. Venus is very bright.

Due to the coronavirus there will be no public viewings scheduled this month. If things change, we’ll post it on TAS’s events calendar.

1st: Moon below Jupiter with Saturn to their right in the morning sky.

2nd: Last quarter Moon, Jupiter, and Saturn form a line.

10th: New Moon.

13th: Moon above Mars near the Beehive Cluster in the evening sky after sunset in the west.

15th: Moon near bright star Regulus in Leo the Lion.

18th: First quarter Moon.

19th – 20th: Moon near bright star Spica in Virgo the Virgin in the evening and into the morning sky.

20th: The summer solstice – summer begins in the Northern Hemisphere.

21st: Venus forms a line with the bright stars Castor and Pollux in Gemini the Twins just after sunset in the west.

22nd – 23rd: Moon near bright star Antares (“Rival of Mars”) in Scorpius the scorpion in the evening and into morning sky.

23rd: Mars passes in front of the Beehive Cluster. Great view through binoculars just after sunset in the west.

24th: Full Moon.

27th: Moon below Saturn with Jupiter to their left in the morning sky.

28th: Moon between Jupiter (to the left) and Saturn (to the right).

29th: Moon below and left of Jupiter.

30th: Moon, Jupiter, and Saturn form a line.

Check out TAS’s events calendar at www.stargazers.org.

Ken Kopczynski is president of the Tallahassee Astronomical Society, a local group of amateur astronomers.

Never miss a story: Subscribe to the Tallahassee Democrat using the link at the top of the page.


Why is sunset on 21st of June not the latest? - Astronomy

I noticed this past December that the sun started setting later in the evening several days before the winter solstice. Why doesn't the earliest sunset occur on the shortest day of the year? Is the fact that the Earth is at perihelion in January have anything to do with the phenomenon?

Our clocks are synchronized with the "mean solar day", which is the motion of the Sun if the tilt of the Earth's axis (or obliquity) is zero and the orbit of Earth were perfectly circular (ie. zero ellipticity). So, first let us consider the case when the obliquity and ellipticity are zero. Then, the ecliptic (the plane of the solar system and the path of the Sun in the sky with respect to the stars) will coincide with the celestial equator. As the clock is perfectly synchronized with the Sun, it will always be on the meridian at 12:00 pm.

But actually the Earth's axis is tilted at 23.5 degrees. Hence, the ecliptic is tilted with respect to the celestial equator by 23.5 degrees. So what happens? Consider the fall equinox point. If the obliquity were zero, from day to day the Sun would move along the celestial equator (this is the motion due to Earth's revolution around the Sun not due to the Earth's rotation on its axis), but since the obliquity is actually 23.5 degrees, the Sun will move at an angle of 23.5 degrees to the celestial equator, or it will move both south and east.

Now, compare how much east the Sun has moved in the two cases (the case where obliquity is zero and the case where obliquity is 23.5 degrees). One can see that the Sun has moved more east in the case where obliquity is zero. Hence, the Sun will be on the meridian (meaning local noon) before the clock has indicated 12:00 pm since the Sun has moved less eastward as it would have if the Earth's obliquity is zero. Since the clock is always synchronized to the "mean Sun", this error (between local noon and the clock's 12:00 pm) will keep growing.

Now, as the Sun moves progressively south, note that the longitudinal lines of right ascension get more cramped together. Also, note that near the winter solstice point, the motion of the Sun is along the declination of -23.5 degrees, which means that the Sun is moving purely eastward. Combining the two facts, one finds that near solstice, the Sun moves eastward faster than what it would have if the obliquity were zero. Hence, at some point, the difference between local noon and the clock's noon will diminish and reduce to zero. This happens exactly at the solstice point. Beyond the solstice point, the Sun is still moving eastward faster than the "mean Sun". Hence, local noon will happen after the clock's noon.

As the Sun passes towards higher declination as it goes from winter solstice to spring equinox, the effect above reverses and the local noon and clock's noon coincide again at the equinox point. Thus, due to obliquity alone,

  • local noon and the clock's noon will coincide at solstices and equinoxes.
  • After equinox, the clock's noon will occur after local noon.
  • After solstice, the clock's noon will occur before local noon.
  • The maximum deviation between the clock's noon and local noon turns out to be about 9 minutes and 40 seconds.

Hence due to obliquity alone,

  • Local noon will occur successively later between early November and early February.
  • Local noon will occur successively earlier between early February and early May.
  • Local noon will occur successively later between early May and early August.
  • Local noon will occur successively earlier between early August and early November.

Hence, as one approaches winter solstice, sunrise wants to become earlier and sunset wants to become later. But as local noon is becoming later than the clock's noon, this shifts the sunrise and sunset time later. The combination of these two gives rise to the later sunset before actual winter solstice, even though the day is still becoming shorter. Note that we have considered only obliquity and have assumed that the orbit is circular.

Now, let us see what happens due to ellipticity of Earth's orbit alone. Hence, let us set obliquity to be zero. If the orbit of Earth were circular, then the time between two local noons will be the same throughout the year. But because the orbit of Earth is elliptical, it moves faster than average near perihelion (near January) and slower than average near aphelion (near July).

Draw a picture of the Sun in the center with the Earth going around it. A star is at infinite distance in comparison. Now, draw the Earth at one location and mark the location of noon. Now, as the Earth rotates, it also moves in its orbit mark a location on the orbit where the point you marked on the Earth has noon again. This period is the mean solar day. (As a side fact, note that the mean solar day is different from the time taken for Earth to rotate once around itself). Now, if the Earth were moving faster than average, it would have moved more in its orbit in the same amount of time, and so the location you marked on Earth will not have noon. The Earth would have to rotate more for the location to have noon. Hence, local noon will occur later than the clock's noon near perihelion. The opposite effect happens near aphelion when Earth moves slower than average, and hence local noon happens earlier than the clock's noon. Here also, errors add progressively around perihelion and subtract progressively around aphelion.

Hence, due to ellipticity alone,

  • Local noon occurs progressively later between October and April.
  • Local noon occurs progressively earlier between April and October.
  • The maximum deviation between local noon and clock's noon turns out to be around 8 minutes.

Now let us combine the two effects and see what happens near winter solstice: Obliquity and ellipticity both conspire to make local noon later than clock's noon near winter solstice. Hence, this shifts sunrise and sunset timings later (note that without this effect, sunrise will become later and sunset will become earlier). The overall effect is that sunset starts becoming later before actual solstice even though the day is becoming shorter.

This page was last updated on June 27, 2015.

About the Author

Jagadheep D. Pandian

Jagadheep built a new receiver for the Arecibo radio telescope that works between 6 and 8 GHz. He studies 6.7 GHz methanol masers in our Galaxy. These masers occur at sites where massive stars are being born. He got his Ph.D from Cornell in January 2007 and was a postdoctoral fellow at the Max Planck Insitute for Radio Astronomy in Germany. After that, he worked at the Institute for Astronomy at the University of Hawaii as the Submillimeter Postdoctoral Fellow. Jagadheep is currently at the Indian Institute of Space Scence and Technology.


Still no morning Sun

We may have reached our shortest day, but unfortunately it will be a few more weeks before our mornings get any brighter. In fact, sunrise will shift slightly later (by a couple of minutes) and it won’t be until July that the trend will start to shift. Bad news indeed for those of us who struggle to get going in the morning.

But our days are still getting longer, just the extra daylight is added to our afternoons, not our mornings.

It’s a pattern that happens around the time of the solstice. At the winter solstice, the earliest sunset (or shortest afternoon), happens first, then the solstice (shortest day), followed by the latest sunrise (or shortest morning).

It works in the opposite way for the summer solstice in December. The earliest sunrise comes first (or longest morning), then the solstice (longest day), then the latest sunset (longest afternoon).


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