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Aftermath of the solar eclipse

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POSTED BY: Marco Thiel
16 Replies

For anyone looking for more resources ahead of the April 8, 2024, eclipse (especially Wolfram Language resources for computing and analyzing eclipses), check out Stephen Wolfram's new book "Predicting the Eclipse: A Multimillennium Tale of Computation". You get a copy on Amazon: https://www.amazon.com/Predicting-Eclipse-Multimillennium-Tale-Computation/dp/1579550878

POSTED BY: Paige Vigliarolo

enter image description here -- you have earned Featured Contributor Badge enter image description here Your exceptional post has been selected for our editorial column Staff Picks http://wolfr.am/StaffPicks and Your Profile is now distinguished by a Featured Contributor Badge and is displayed on the Featured Contributor Board. Thank you!

POSTED BY: Moderation Team

I mention all of you and your ideas in this blog: Solar Eclipses from Past to Future, Earth to Jupiter. Thanks for wonderful contributions and fun!

POSTED BY: Vitaliy Kaurov

This related discussion seems very interesting to me: Solar eclipses on other planets

POSTED BY: Vitaliy Kaurov

To highlight the diversity of the discussion we can use new in Wolfram Language function WordCloud:

post = Import["http://community.wolfram.com/groups/-/m/t/463721"];
Row[{
  WordCloud[ToUpperCase[DeleteStopwords[post]],
   ColorFunction -> "RustTones", Background -> Black, 
   ScalingFunctions -> (#^.1 &)],
  WordCloud[ToUpperCase[DeleteStopwords[post]],
   ColorFunction -> "RedBlueTones", ScalingFunctions -> (#^.1 &),
   Background -> ColorData["RedBlueTones"][0], 
   WordOrientation -> {{0, \[Pi]/2}}]}]

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In the code above there are three handy tricks. First is that option WordOrientation has diverse settings for words' directions. Second is that a good choice ScalingFunctions can grant a good visual a peal, and simple power low I've chosen is often more flexible than logarithmic one. The third trick is subtler. It is the choice of background color to be the "bottom" color of the used ColorFunction. Then not only sizes of the words stress their weights, but also fading out into the background.

POSTED BY: Vitaliy Kaurov
POSTED BY: Marco Thiel

Hi Marco,

inspired by your and Sander's posts on how much the sun was covered during the last eclipse, I also tried to write an evaluation from picture data. For this I use Tanvi's first picture (@Tanvi: Thanks for posting!), because in the second one the sun seem to be "cut" a bit at the edges by clouds. My ansatz is to use a model of the eclipse consisting of two equal sized disks overlapping each other. This simple model has five parameters (the number on the right side represents a fitness of match):

enter image description here

One can define a "fitness function" to quantify the goodness of match and try an optimization for this. Unfortunately I was not able to get that working perfectly - the result of NMaximize is not bad but by no means perfect. This seems strange because it is very easy to improve the solution by hand.

Once a result is obtained, e.g.:

enter image description here

one can very easy calculate the covering:

\[ScriptCapitalR] =  RegionDifference[Disk[{x, y}, r], Disk[{x + dr Cos[\[Phi]], y + dr Sin[\[Phi]]}, r]] /. opt;
Print["covering: ", 100 (1 - RegionMeasure[\[ScriptCapitalR]]/(Pi r^2) /. opt), "%"]

Otherwise I would not have a quick idea on how to do that - probably some ugly integrals ...

I have attached the notebook with the code. The next solar eclipse may come!

Henrik

Attachments:
POSTED BY: Henrik Schachner

Dear Henrik,

that looks really great. I was aware that my method was quite flawed. I only cover he crescent with a disk which is by no means ideal. I hoped to be able to use a bit of maths to correct for that. Your Manipulate GUI is really nice! Thanks for sharing.

Best wishes,

M.

POSTED BY: Marco Thiel
POSTED BY: Marco Thiel

Marco, thank you for such extended reply! Do you think the types of data you were mining here have significance for the global warming discussion? Have you or your team ever done research in that direction?

POSTED BY: Vitaliy Kaurov
POSTED BY: Marco Thiel
POSTED BY: Marco Thiel

Thanks you for a very interesting analysis, professor Thiel. Here are a few pictures of the eclipse from Aberdeen, around 9:25 am. enter image description here

enter image description here

POSTED BY: Tanvi Chheda
POSTED BY: Vitaliy Kaurov

Thanks Dr. Kaurov, I took the photos on an iPad, there's no processing done on the pictures.

POSTED BY: Tanvi Chheda

Great Marco, excellent detective work ;) We know it was clear in Aberdeen on the eclipse day:

enter image description here

So I am curious - have you seen the eclipse - you must have had almost 100% sun coverage ? Also I am looking forward to doing a similar data digging when total solar eclipse will spam USA in 2017 - I just posted about the path of it (image below) - I hope folks in US will have similar devices that you featured.

enter image description here

POSTED BY: Vitaliy Kaurov
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