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Questions tagged [solstice]

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Based on what grounds can people predict winter & summer solstices?

I asked different AI sites about the formula to calculate the date of the Winter solstices. All of them give me unrelated answers or saying there are no definite equations to do that. If the Winter/...
Hoy Cheung's user avatar
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0 answers
59 views

How can I build a gear-based mechanism to calculate solstices, equinoxes, and cross-quarter dates?

I realize there are boundless amounts of information as to the formulas to calculate solstices, equinoxes, and cross-quarter days, but I would like to design a gear-based mechanical solution for the ...
Eriks's user avatar
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4 votes
1 answer
240 views

What is the distance between sunrise and sunset along a parallel of latitude for declination other than 0?

I would like to calculate the distance between sunrise and sunset along a parallel of latitude, e.g., 45 degrees north. What I've done is: Earth's circumference at the equator is 40075 km. Earth's ...
Geographos's user avatar
6 votes
1 answer
310 views

Geometric effect on sun's position in the sky at the equator

This question is about an explanation of "Sunrise and Sunset Times Near the Solstices" on the official website of the US Naval Observatory. It is mentioned in the explanation article that, ...
Jacob Miller's user avatar
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1 answer
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How did ancient models explain 6 months of day and night at the respective poles?

We know that the Arctic circle experiences 6 months of continuous day light during the sun’s apparent northward journey (to the solstice) and vice verse for the Antarctic region. This is attributed to ...
Adiyarkku's user avatar
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8 votes
1 answer
857 views

How do I calculate the moment of the solstice?

I'm trying to calculate the moment of the upcoming summer solstice using astropy, and I can't seem to get an answer that matches the accepted values that I see online. I thought that the moment of the ...
Roy Smart's user avatar
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27 votes
3 answers
5k views

Why is the solstice the first day of summer, and not the central day?

Summer in the Northern Hemisphere starts on the day of the summer solstice. This is the day that the Northern Hemisphere receives more light from the Sun, due to the Earth's tilt. To my knowledge, the ...
DaniPM93's user avatar
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1 vote
1 answer
295 views

Do we get shortest shadow of any object at Solstice time or Meridian time?

Today is 21 June and I want to see at what time I will see shortest shadow in my location. I am seeing two different times: Solstice time a d Meridian time. I read that on summer solstice the sun is ...
Vikas's user avatar
  • 341
9 votes
1 answer
592 views

When exactly was the last time that Earth's aphelion coincided (within 24 hours) with the northern winter (December) solstice?

I would like to know in what year precisely did Earth's aphelion coincide (within 24 hours) with the northern winter (December) solstice? From what I understand, the day (on any tropical calendar) on ...
A. Bear's user avatar
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4 votes
1 answer
163 views

Confusion when calculating the length of the day

I'm trying to solve this task: Tula and Moscow are located on the same meridian. In which city length of the day is bigger on 22 of June? 22 of December? I was thinking like that: we need to ...
ALiCe P.'s user avatar
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11 votes
3 answers
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Why is today the shortest day but the solstice is actually tomorrow?

Here in Ashland, Oregon, today (Dec 20, 2020) is the shortest day length of the year at 9:05:45. But the winter solstice isn't until 2:02 AM PST tomorrow (Dec 21, 2020). Tomorrow's day length is a ...
DevonTaig's user avatar
  • 229
4 votes
2 answers
383 views

Will I be able to see both Jupiter and Saturn at the same time in my Astromaster 114?

I have a Celestron Astromaster 114 Newtonian reflector telescope. The specs: aperture: 114mm focal length: 1000mm focal ratio: f/8.77 I also have a t-ring so I can connect a Nikon camera to it. Will ...
S. Imp's user avatar
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6 votes
1 answer
1k views

Are the Jupiter-Saturn conjunctions and winter solstice related?

There is conjunction of Jupiter and Saturn on Dec 21. And there is another celestial event on that day the winter solstice. So I'm just wondering that are these two events are related or not?
Usama's user avatar
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6 votes
4 answers
480 views

Aligning the equinoxes to the cardinal points on a circular calendar

I want to draw a calendar as a circle, with the equinoxes at the top and bottom, and the solstices at the left and right. I am prepared to accept a little inaccuracy by having exactly 365 or 366 days ...
PhilHibbs's user avatar
  • 163
6 votes
1 answer
661 views

When was the last time a great conjunction coincided with a solstice?

This December, a great conjunction will occur nine hours after winter solstice, which means that for much of the world the two events will be on the same day. When was the last time a great ...
Max Radin's user avatar
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18 votes
2 answers
2k views

What will the PRECISE time of the Summer Solstice 2020 be?

I'm trying to explain to my daughter that the Summer Solstice is not a day of the year, but an exact instant in time. My search shows that this will be about 21:43 or 21:44 UTC tonight. To make my ...
David Dubois's user avatar
2 votes
1 answer
753 views

Earth's perihelion vs winter solstice [duplicate]

I found that Earth's perihelion occurs roughly two weeks after winter solstice similar thing happens for summer solstice and aphelion. I understand what those terms mean but I don't understand the ...
griffins's user avatar
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4 votes
1 answer
566 views

Aphelion and the solstice

We have just passed one of the solstices and are approaching aphelion. The two events are close but not simultaneous. There is no very obvious (to me) reason why the two should coincide or be close. ...
badjohn's user avatar
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3 votes
0 answers
439 views

How to calculate planetary positions hundreds or thousands of years ago

Wondering how to calculate the following in a general way: Sunrise/sunset Equinoxes/solstices Moon phases Planetary positions For hundreds to thousands of years ago. Wondering what the calculation ...
Lokasa Mawati's user avatar
1 vote
1 answer
492 views

Date of solstices pre-0 AD

I’ve written a script based on Meeus’s Astronomical Algorithms to calculate the position of the sun, moon etc. up to about 4000 BC. Everything looks good, except when I go to 4000 BC the solstice are ...
Robbarratt1's user avatar
2 votes
4 answers
741 views

Why is the equinoxes only 2 days and not more?

The earth is tilted at 23.5 degrees which means that in the solstices the north/south hemisphere is more radiated by the sun and the tilt to the sun is maximum. In the equinoxes, the tilt is not ...
Jim's user avatar
  • 263
2 votes
1 answer
184 views

Solar azimuth for celtic fire festivals

I am pretty new to astronomy, and I have fallen down rabbit hole creating a new Metonic calendar in Javascript. As part of this I would like to calculate when the sun is half way between a solstice ...
Mark Jones's user avatar
10 votes
2 answers
1k views

Why is the time between equinoxes different?

The path of the Earth around the sun is described as being an ellipse, with the Sun being at one of the foci of the ellipse. Since an ellipse, by definition, is symmetrical with respect to the foci, I ...
Tyler Durden's user avatar