Topic: Daylight vs. Sunrise/Sunset?

[WeatherHost]

Lots of charts, tool and calculators out there based on Sunrise/Sunset but that's when the Sun breaks or falls over the horizon.  It's often 'daylight' long before and well after those times.

Anybody have a favorite source for that?

[Jáchym]

I have taken this into account in my template.

Basically what you are referring to is "twilight".

There are various angles assigned to particular twilights. There are three established and widely accepted subcategories of twilight: civil twilight (brightest), nautical twilight, and astronomical twilight (darkest).

Definition is here: http://www.timeanddate.com/astronomy/different-types-twilight.html

Example where I used the data from the above page in terms of the angles: http://www.meteotemplate.com/template/pages/astronomy/sun.php (look at day graph tab)

[Cutty Sark Sailor]

http://aa.usno.navy.mil/faq/docs/RST_defs.php  http://aa.usno.navy.mil/data/index.php
http://www.esrl.noaa.gov/gmd/grad/solcalc/

[Scalphunter]

Weather display show them. Also most newspapers. If one wants to see the effects come north or go far south. Long lingering twilights. Summer here has only sunrise sun set. Late July we start getting civil twilight. Nautical twilight comes in August and finally in Sept we get a stromal twilight.

Also good nautical a lama will has them as one need to know them for celestial navigation.  Lot of fun doing star shots while doing slow roll.

John

[ACWxRADAR]

This thread is a few months old, but...

I was browsing the forum searching for neat topics of interest and this one grabbed my attention...  Which isn't easy.......  Oh look!  A squirrel!  Excuse me, where was I?  Oh yeah...  Twilight.

I was thinking about this subject recently because of the upcoming end of Daylight Saving Time.
Which occurs on November 1, 2015 at 2:00 a.m.  I wish we could leave the time thing alone.  Set it and forget it!  I wouldn't really care which way, really, I just hate changing it.

Anyway, here is a nice pictorial (pix) to explain the different twilight timeframes:

[Jáchym]

Here in Europe we changed the time this last weekend already

[ACWxRADAR]

Here in Europe we changed the time this last weekend already

That is understandable, since the sunrise greets Europe before it does North America!  Ha Ha

That is an inside "joke" of sorts.  I was showing a co-worker some pix of Wels Catfish (big ones) and he exclaimed that they (all catfish in general) were bigger in Europe because Europe had been there longer!  HA!!! 

Don't ask me to explain either comment above as I think an aneurism would result.
 
RADAR