User talk:StephenHudson

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DYK: Climate of the Arctic
Keep up the good work. Climate of Arctic is another major article which was missing. I'm currently working on Deforestation in Brazil ♦ Sir Blofeld ♦      "Talk"? 15:37, 8 December 2007 (UTC)

Climate of the Arctic
There is a reply posted at talk regarding possible article improvements. Good job on the article to date! SriMesh | talk  22:10, 20 August 2008 (UTC)
 * Your DYK hook has been added to the newly created Portal:Arctic.

Lenght of Civil Twilight Graph
Hello Stephen,

I am curious about your graph Image:TwilightLength.png. You give a link to the fortran code used to calculate solar angle, but did not state explicitly the angles you were seeking and how you drove the code.

In the image description "Length of civil twilight, ..." you state, "Civil twilight begins before sunrise when the sun is geometrically 6 degrees below the horizon and ends after sunset when the sun is geometrically 6 degrees below the horizon". This is true, but those are the start and end of two different civil twilights. In my understanding, morning civil twilight ends at sunrise and the evening civil twilight starts at sunset.

I infer that your graph shows the length of time between the sun being 6 degrees below the eastern horizon to it being 6 degrees below the western horizon. This yields the sum of the lengths of both civil twilight and daylight.

Your graph Image:DayLength.png again does not state the angles you were seeking, but I assume that you calculated the time between the center of the sun being 0.25 degrees below the horizon, rising to setting. The length of twilight would then be the difference of these two graphs, or one indicating the time for the sun to travel from 6 degrees below the horizon to 0.25 degrees below the horizon (or vice versa).

This new graph will still have periods of continuous civil twilight at extreme latitude, but they will not last all summer, and the periods of continuous civil twilight at the two poles will not overlap.

Also, I am curious what program you used to generate the actual graphs.

Finally, I am left wondering if in some circles the term "twilight" includes daylight. Have you found this to be the case?

Thank you for your work, particularly your Climate of the Arctic article. Kirk Hilliard (talk) 14:47, 15 September 2008 (UTC)


 * Hi Kirk,


 * Thanks for the interest in this, and the good questions/comments. I made these quickly, and was a little sloppy about details since, plotted on this scale, they would not change things much.  I've updated the descriptions to include answers to some of your questions.


 * The angles I searched for were 0° for sunrise/set, and -6° for twilight, ignoring the diameter of the sun in the case of rise and set.


 * I agree that those are two different civil twilights, and tried to clarify that by describing the TwilightLength image as showing the duration of daylight and explaining what I meant by that. I am not aware of 'twilight' being used to include the period when the sun is up.


 * I used Matlab to generate the plots, and used Adobe Illustrator to make them more easily readable and to export them to png and svg formats.


 * I have made a similar plot for just the time each day with civil twilight (solar elevation between 0 and -6°) which you can see at http://www.stephenhudson.net/civilTwilightTimes.pdf . The times there are the total of both periods of civil twilight, or the length of the single civil twilight period if the sun does not rise.  StephenHudson (talk) 11:01, 23 September 2008 (UTC)

A study on how to cover scientific uncertainties/controversies
Hi. I would like to ask whether you would agree to participate in a short survey on how to cover scientific uncertainties/controversies in articles pertaining to global warming and climate change (survey described here). If interested, please get in touch via my talkpage or email me Encyclopaedia21 (talk) 21:01, 5 June 2009 (UTC)

The added "s"
Hey, thanks for catching that. Not sure what happened - probably aiming for something immediately above or below it on the watchlist - but I'm glad you were paying attention. Cheers. --Ckatz chat spy  08:18, 28 July 2010 (UTC)

Arctic
Thank you for helping me by fixing the ref in Arctic. In my opinion the news deserved notice since it gave the latest status. Watti Renew (talk) 14:21, 20 September 2011 (UTC)

Arabic Alphabet
You were quite right to undo my edit - my sensible nature was ambushed by the spuriousness of the idea 20:08, 14 November 2012 (UTC) — Preceding unsigned comment added by Gwaka Lumpa (talk • contribs)

ArbCom elections are now open!
MediaWiki message delivery (talk) 12:57, 23 November 2015 (UTC)