Questions tagged [the-sun]

Questions regarding the closest star to Earth, at the centre of the Solar System.

35 questions with no upvoted or accepted answers
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7
votes
1answer
177 views

First observation that the Sun and Jupiter (and friends) move around a common barycenter?

Answers to the question How did Kepler determine the orbital period of Mars? describing careful observations centuries ago got me thinking. What was the first analysis of observations that directly ...
5
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0answers
100 views

Which astronomer set his beard on fire because he left the cap off his telescopes finder?

There is a famous story of an experienced astronomer setting his beard on fire because he left the cap off his telescopes finder. I know it's said to be true of Galileo, but I thing it's relatively ...
4
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41 views

Simulate earth, moon, sun constellation with dates

I would like to simulate the three object distance, specifically the distance of the moon to both, sun and earth for further investigation into tide prediction. What would be a good starting point ...
4
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0answers
72 views

“Pluto Time” for any solar system body

A while back NASA made a site called Pluto Time, where you can enter your address and find that "...moment near dawn and dusk each day, where the illumination on Earth matches that of high noon on ...
4
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0answers
266 views

Linear limb darkening coefficient, u

I was wondering if anyone knew of any resources to understand the linear limb darkening coefficient, $u$. That is to say, how the $\theta$-dependent coefficient $u$ (or sometimes $b_{\nu}$) varies ...
3
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0answers
60 views

Does the Sun have a numerical designation in any star catalogues?

Given the existence of large star catalogues listing millions of astronomical objects with numerical designations (such as Tabby's Star, KIC 8462852) it occurred to me that one of them might contain ...
3
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0answers
61 views

Did Eudoxus describe the eclipitic on his sun motion model?

In the description of Eudoxus’s model for the sun he says one the three circles which describe solar motion is “the circle which runs along the middle of the zodiac”. Does this refer to the ecliptic ...
3
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0answers
46 views

How does the geometry for constructing a declining vertical sundial work?

I understand how to construct South-facing vertical an horizontal sundials and the geometry behind their construction by projecting an equatorial sundial into a plane, but I can't quite get how to do ...
3
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0answers
58 views

Erratic Sundial

My sundial shows real time until 11am when it will drop behind an hour until sunset. This is in keeping with daylight saving but why does it show real time before 11am? Am I missing something ...
3
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0answers
70 views

Is there any formulae to calculate whether the sun will depress 18 degrees or more below the horizon on a certain day / location?

I'm trying to code a piece of software which will calculate some times for me that would greatly help me in my day to day but none of my formulae work if the sun doesn't go at least 18 degrees below ...
3
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0answers
161 views

What are the experimental limits to the residual charge of the Sun?

The question Can a Neutron Star become charged? and the associated comments and answers started me wondering; Are there measurements of, or experimental limits to the residual charge of the Sun? ...
3
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0answers
119 views

Kepler - Creating the Ellipse (Astronomia Nova)

In Chapter 58 in Astronomia Nova, Kepler made his final step to finally create the ellipse (for the orbit of planets) http://science.larouchepac.com/kepler/newastronomy/part4/58/index.html In the ...
2
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1answer
77 views

Latitude of given altitude of Sun

From Question #6 of USAAAO First Round 2018 (1 point) For the following problem find the range in which the answer lies: on the day of summer solstice, on which geographic latitude is the sun ...
2
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0answers
83 views

Orbital decay of the Earth's orbit and Earth's moving closer to the Sun

If we consider orbital decay of the Earth's orbit, then can we counter argue with the following reasons? Due to tidal effects transferring small amounts of angular momentum from the Sun's spin to ...
2
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0answers
36 views

Aaditya L1 mission ISRO

ISRO's next mission to the Sun is Aditya-L1, (also here), which will be placed at the Sun-Earth Lagrangian point L-1. Why it is not placed near L-4 or L-5, since these are stable equilibrium point ...
2
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0answers
57 views

How to get SOHO Satellite images' coordinates?

I'm working with images from LASCO C3 coronagraph I'm able to download pictures from LASCO C3 using this form https://sohodata.nascom.nasa.gov/cgi-bin/data_query Then, I want to do some analysis of ...
2
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0answers
467 views

How is the time of sunrise and sunset determined?

If I do a quick Google search for amsterdam sunrise, I immediately get the time back: 6:42 AM. How is this time calculated? (I ...
2
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0answers
157 views

Observed sun/moon rise/set times to nearest second?

Where can I find a list of observed (not computed) sun/moon rise/set times to the nearest second, along with the location (latitude, longitude, altitude [or enough information to find these three ...
2
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1answer
70 views

How well can the Sun's surface be resolved by an observatory?

There's no lack of photons, how well could a telescope resolve Sun spots and other surface features of the Sun? How would a high resolution Solar (space) telescope differ from for example Hubble which ...
1
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0answers
12 views

Why do CME's “zig-zag” on their way to Earth?

This answer states: A single CME will impact a spacecraft from only one direction, but that direction might not be directly from the sun because a CME may zigzag en route. Looking at that link, ...
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27 views

Angle of the Sun during winter solstice

What is the angle of the Sun on the eastern horizon at 35° latitude if it is the winter solstice?
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40 views

Angle between earth's angular momentum and earth's axis

I think this picture is correct because for earth astronomical day is slightly shorter than solar day. (Is it a rule of thumb for planets? Where can I read such data?) Source So the angle between ...
1
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0answers
41 views

Looking for a 3D animation showing the motion of the sun relative to other stars and the Milky Way, any one seen anything like that?

I am looking for an animation that not only shows the inclination of the solar system respective to the plane of the galaxy, but also shows the motion of the sun relative to and in conjunction with (i....
1
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0answers
103 views

What is the great (platonic?) year? How could it be explained in laymen's terms?

How could a great year be explained in laymen's terms? According to the definition in NASA's Aerospace Dictionary it is a complete cycle of the equinoxes around the ecliptic that completes in 26000 ...
1
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0answers
47 views

Tracking a heliographic coordinate on CCD

Given the latitude and longitude of a heliographic coordinate, I want to place the point on a CCD image and simulate its motion for a particular duration. Though I am able to track the motion of a ...
1
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0answers
38 views

Tracing back OMNI data to the sun

I have been reading the OMNIWeb data documentation in order to clarify one particular question without success. I need to associate each measurement in the OMNI dataset to a moment in time at the sun (...
1
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0answers
169 views

How do I calculate the barycentric position of the sun at a given julian date?

I have used the (matlab/octave) SOFA routine/function iauEpv00 to get the barycentric position and velocity of the Earth, but now need to find barycentric position of the sun. Can't seem to find the ...
1
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0answers
57 views

Visible Light Ground-Based Solar Observatory Data Archives?

I'm mainly searching for the best(or good/significant/important) solar data archives via ground-based telescopes. If I'm not being very straightforward... Say if I wanted high quality/resolution ...
0
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0answers
44 views

IAO 2015 Question 1 Noon at the Olympiad

Yesterday, on October 16, 2015, the upper culmination of the Sun at the venue of the Olympiad was at 11:29:44 local time. Calculate as accurate as possible at what time the upper culmination of the ...
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26 views

what/how do we mean/derive statistical equilibrium equation of certain energy levels?

While reading the research paper "Excitation of the Fe XIII Spectrum in the Solar Corona" by D.R. Flower and G. Pineau des Forets in the summary I found the concept of statistical equilibrium equation ...
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14 views

Did OSO-3 or any other spacecraft or ground telescope record the solar activity that is likely the cause of the May 1967 aurora?

The question What solar event caused massive aurora borealis in the mid 1960's? reminds me again of a stunningly bright aurora that I saw circa 40°N circa 1967, and after reading the comments and ...
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34 views

What should be the seperation between sun and moon during a solar and lunar eclipse as viewed from earth?

I saw this code online where a guy calculates the separation between sun and moon and verify the occurrence of eclipses. You can find the codes here. Why does he uses earth's angular size seen from ...
0
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0answers
418 views

Complete Sun altitude-temperature graph?

I found a bunch of partial graphs. For interior: src For surface: src The closest thing I could find that would cover more than innermost piece of corona is for sigma binaries. As if solar corona ...
-1
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1answer
93 views

Where can I still find solar film?

I, like many others, am excited to see the eclipse. I want to view the eclipse through my telescope, however, I don't have any solar safety equipment for solar viewing and I cannot find any online ...
-4
votes
1answer
414 views

What percentage of the sky could the sun be in?

For every location on earth, there are parts of the sky that the sun can never be in (e.g., directly overhead anywhere outside the tropics). I think the sun can be in about 40% of the sky (a ...