APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

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APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by APOD Robot » Mon Sep 23, 2019 4:08 am

Image Equinox: The Sun from Solstice to Solstice

Explanation: Today is an equinox, a date when day and night are equal. Tomorrow, and every day until the next equinox, the night will be longer than the day in Earth's northern hemisphere, and the day will be longer than the night in Earth's southern hemisphere. An equinox occurs midway between the two solstices, when the days and nights are the least equal. The featured picture is a composite of hourly images taken of the Sun above Bursa, Turkey on key days from solstice to equinox to solstice. The bottom Sun band was taken during the north's winter solstice in 2007 December, when the Sun could not rise very high in the sky nor stay above the horizon very long. This lack of Sun caused winter. The top Sun band was taken during the northern summer solstice in 2008 June, when the Sun rose highest in the sky and stayed above the horizon for more than 12 hours. This abundance of Sun caused summer. The middle band was taken during an equinox in 2008 March, but it is the same sun band that Earthlings see today, the day of the most recent equinox.

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by Chris Peterson » Mon Sep 23, 2019 4:16 am

Oh, oh... how long until the regular (and rather lame) complaint that day and night aren't equal on the equinox? Counting down...
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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by BDanielMayfield » Mon Sep 23, 2019 4:56 am

Chris Peterson wrote:
Mon Sep 23, 2019 4:16 am
Oh, oh... how long until the regular (and rather lame) complaint that day and night aren't equal on the equinox? Counting down...
We can hope that your comment serves as a deterrent ...
"Happy are the peaceable ... "

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by orin stepanek » Mon Sep 23, 2019 11:51 am

Nice job with the pictures of the sun! I'm not sure I'm ready for shorter days though! :?
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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by neufer » Mon Sep 23, 2019 12:30 pm

Click to play embedded YouTube video.
BDanielMayfield wrote:
Mon Sep 23, 2019 4:56 am
Chris Peterson wrote:
Mon Sep 23, 2019 4:16 am

Oh, oh... how long until the regular (and rather lame) complaint that day and night aren't equal on the equinox?

Counting down...
We can hope that your comment serves as a deterrent ...
... because it might be pleasant to remember upon Solstice Day,
who made lame complainants walk, and blind men see.
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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by bjmb » Mon Sep 23, 2019 3:12 pm

Today is an equinox, a date when day and night are equal
***
perhaps in los angeles, but not in am*dam:
07:27
Maandag 23 september 2019 (CEST)
Zonsopgang in Amsterdam
19:37
Maandag 23 september 2019 (CEST)
Zonsondergang in Amsterdam
***
i must be the dullest person on this forum, but i can't for the life of me see what is difficult about writing: 'one of only two dates when day anywhere on earth is longer than night.' that, to my mind, is what makes the equinoxes special, not an (astronomically impossible) equilux for the whole earth.
my good friend dave the penguin texts me from the south pole that he is so happy midnight sun is back. no more night until march.

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by De58te » Mon Sep 23, 2019 3:24 pm

Happy Equinox Day everybody. If I can maybe give an explanation, today in my area the day is about 8 minutes longer than the night.(according to the sunrise/sunset charts.) It will be about equal, 1 minute difference, 3 days from now on Sept 26. The reason why is that astronomy wise the Sun is measured from its centre whereas sunrise and sunset are measured just when the limb of the sun peaks up over the horizon or sinks below. There are a few minutes before the centre of the Sun crosses the horizon. In addition there is also the phenomenon of refraction. An illusion as light crosses the border of two different mediums. For example a spoon in a glass of water appears bent between the medium of the water and the air.

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by MarkBour » Mon Sep 23, 2019 3:32 pm

I love images like today's APOD! It looks like summer solstice at that location was about 15 hours of daylight, the equinox 12, and the winter solstice about 8 hours of daylight. The location of the camera is a great location for solar panels ... no significant blockage!
Chris Peterson wrote:
Mon Sep 23, 2019 4:16 am
Oh, oh... how long until the regular (and rather lame) complaint that day and night aren't equal on the equinox? Counting down...
Ok, refraction / the edge of the disk versus center of disk / exact moment of equinox, yada yada yada ?
Happy to oblige.
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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by canopia » Mon Sep 23, 2019 4:28 pm

Thank you Mark. I had photographed this image from the rooftop of our apartment building in Bursa, Turkey; located at 40° 11' N, 29° 4' E. -There are already inevitable messages about the duration between sunrise and sunset being longer than 12 hours on equinox days. This is further complicated by horizon profiles; like at my location.

For the December solstice, the Sun should normally rise at 07:23 local time (GMT+2) and after a short 9 hours 18 minutes of day, it would set at 16:41. But due south and southeast of Bursa lies Uludağ, a mountain rising 2.5 km and blocking a considerable sky. So, when I took the first picture when the Sun appeared from behind Uludag, it was 08:11. The sunset was also earlier because of hills due southwest, at 16:03. So, the shortest day of the year was even shorter for Bursa; 7 hours 52 minutes at my location.

On the March equinox day, the sun would rise at 06:07 (GMT+2) and set at 18:16. Because of the clouds, I could take the first picture 3 minutes after the actual sunrise (at 06:14) which was somewhat dimmed by haze; at 06:17. Sunset was less eventful and much easier, at 18:09. That was the equinox, with an actual daylight of 11 hours 55 minutes instead of a not-so-equal day of 12 hours and 9 minutes, those 9 minutes resulting from atmospheric effects and Sun's angular size.

On the June solstice day, sunrise and sunset were predicted to occur at 05:34 and 20:36 daylight time (GMT+3), resulting a longest day of 15 hours and 2 minutes. But the actual sunrise was at 05:53, when the Sun appeared from behind Avdan Dağı, a smaller mountain due northeast rising about 1000 meters. Actual sunset was just a couple minutes earlier, at 20:34; making our longest day 14 hours 41 minutes long.

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MarkBour wrote:
Mon Sep 23, 2019 3:32 pm
I love images like today's APOD! It looks like summer solstice at that location was about 15 hours of daylight, the equinox 12, and the winter solstice about 8 hours of daylight. The location of the camera is a great location for solar panels ... no significant blockage!
Chris Peterson wrote:
Mon Sep 23, 2019 4:16 am
Oh, oh... how long until the regular (and rather lame) complaint that day and night aren't equal on the equinox? Counting down...
Ok, refraction / the edge of the disk versus center of disk / exact moment of equinox, yada yada yada ?
Happy to oblige.

Guest

Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by Guest » Mon Sep 23, 2019 4:54 pm

Why is the sun whiter in the equinox band than in both solstice bands?

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Earthlings laid end-to-end?

Post by neufer » Mon Sep 23, 2019 4:55 pm

APOD Robot wrote:
Mon Sep 23, 2019 4:08 am
Image Equinox: The Sun from Solstice to Solstice

Explanation: The middle band was taken during an equinox in 2008 March, but
it is the same sun band that Earthlings see today, the day of the most recent equinox.
https://apod.nasa.gov/apod/ap080421.html wrote:
Explanation: Phages are very small --
it would take about a million of them laid end-to-end to span even one millimeter.
http://asterisk.apod.com/viewtopic.php? ... 990#p92965
Last edited by neufer on Mon Sep 23, 2019 4:57 pm, edited 1 time in total.
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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by canopia » Mon Sep 23, 2019 4:57 pm

Because there was a layer of high haze, sometimes thin clouds on that day.

Tunç Tezel
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Guest wrote:
Mon Sep 23, 2019 4:54 pm
Why is the sun whiter in the equinox band than in both solstice bands?

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by FLPhotoCatcher » Mon Sep 23, 2019 8:48 pm

Here comes another matter of semantics. Science should be expressed clearly and accurately, so I think it is worth mentioning.
The write-up says, "An equinox occurs midway between the two solstices, when the days and nights are the least equal." Sounds incorrect, and can certainly be misinterpreted.

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by neufer » Mon Sep 23, 2019 9:18 pm

FLPhotoCatcher wrote:
Mon Sep 23, 2019 8:48 pm

Science should be expressed clearly and accurately, so I think it is worth mentioning.

The write-up says,

"An equinox occurs midway between the two solstices, when the days and nights are the least equal."

Sounds incorrect, and can certainly be misinterpreted.
  • I think your concern is misplaced:
https://en.wikipedia.org/wiki/Dangling_modifier wrote:
Strunk and White's The Elements of Style provides [an example of] a misplaced modifier:

I saw the trailer peeking through the window.

Presumably, this means the speaker was peeking through the window, but the placement of the clause "peeking through the window" makes it sound as though the trailer were doing so. The sentence can be recast as, "Peeking through the window, I saw the trailer."

Similarly, in "She left the room fuming", it is conceivably the room, rather than "she", that was fuming, though it is unlikely that anybody besides a fumigator would interpret it this way.

Strunk and White describe as "ludicrous" another of their examples: "Being in a dilapidated condition, I was able to buy the house very cheap." The author obviously meant the house was dilapidated, but the construction suggests that he (the speaker or writer, identified as "I") was dilapidated.>>
Art Neuendorffer

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by MarkBour » Mon Sep 23, 2019 9:30 pm

Thank you, Tunç (canopia), for the replies!
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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by Boomer12k » Tue Sep 24, 2019 3:41 am

Good image and representation...


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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by FLPhotoCatcher » Tue Sep 24, 2019 5:03 am

neufer wrote:
Mon Sep 23, 2019 9:18 pm
FLPhotoCatcher wrote:
Mon Sep 23, 2019 8:48 pm

Science should be expressed clearly and accurately, so I think it is worth mentioning.

The write-up says,

"An equinox occurs midway between the two solstices, when the days and nights are the least equal."

Sounds incorrect, and can certainly be misinterpreted.
  • I think your concern is misplaced:
https://en.wikipedia.org/wiki/Dangling_modifier wrote:
Strunk and White's The Elements of Style provides [an example of] a misplaced modifier:

I saw the trailer peeking through the window.

Presumably, this means the speaker was peeking through the window, but the placement of the clause "peeking through the window" makes it sound as though the trailer were doing so. The sentence can be recast as, "Peeking through the window, I saw the trailer."

Similarly, in "She left the room fuming", it is conceivably the room, rather than "she", that was fuming, though it is unlikely that anybody besides a fumigator would interpret it this way.

Strunk and White describe as "ludicrous" another of their examples: "Being in a dilapidated condition, I was able to buy the house very cheap." The author obviously meant the house was dilapidated, but the construction suggests that he (the speaker or writer, identified as "I") was dilapidated.>>
I think you are misunderstanding the write-up as being correct. Quoting the write-up, "An equinox occurs midway between the two solstices, when the days and nights are the least equal." Doesn't the equinox occur when the days and nights are the MOST equal? If you take the phrase "midway between the two solstices", that would also be when the days and nights are the MOST equal.
(I know the days and nights are not exactly equal everywhere on Earth on the equinox, but close.)
For what it's worth, my sister agrees with me.

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by Ann » Tue Sep 24, 2019 6:29 am

APOD Robot wrote: An equinox occurs midway between the two solstices, when the days and nights are the least equal.
Obviously APOD Robot meant to say:

An equinox occurs midway between the two solstices. The solstices are when the days and nights are the least equal. :wink:

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by bjmb » Tue Sep 24, 2019 9:09 am

"The solstices are when the days and nights are the least equal"
on and around the poles, of course, day and night are always exceedingly unequal, solstice or not - if it is day, there is no night for six months, if it is night, there is no day for six months. there the sun rises only once a year and sets only once a year. among all the points that ruin the nice 'night and day are equal on the equinoxes' there's also the fact that the earth is not spherical but bulges on the equator and is somewhat flattened at the poles.

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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by neufer » Tue Sep 24, 2019 12:31 pm

Ann wrote:
Tue Sep 24, 2019 6:29 am
APOD Robot wrote: An equinox occurs midway between the two solstices, when the days and nights are the least equal.
Obviously APOD Robot meant to say:

An equinox occurs midway between the two solstices. The solstices are when the days and nights are the least equal. :wink:
For folks not already comfortable with the common/sloppy use of misplaced modifiers
that IS what APOD Robot said.

Perhaps APOD Robot should have said:

"An equinox occurs midway between the two solstices."

and simply left it at that.

("The solstices are when the days and nights are the least equal" is a problematic sentence on its own.)
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Re: APOD: Equinox: The Sun from Solstice to... (2019 Sep 23)

Post by MarkBour » Wed Sep 25, 2019 9:07 pm

neufer wrote:
Tue Sep 24, 2019 12:31 pm
... I think your concern is misplaced ...
I try to embrace the sweet ambiguity found wherever there is a misplacement of concern. :D
Mark Goldfain