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-   -   Sunset at FL490 (https://www.pprune.org/tech-log/289394-sunset-fl490.html)

Gulfstreamaviator 25th August 2007 06:43

Sunset at FL490
 
Can anyone throw light on the difference between Sunset at the surface and at FL350 or even FL490.

Simple answers only please....

glf

Deano777 25th August 2007 09:44

At what latitude?

Bullethead 25th August 2007 10:00

So you want to throw some light on the Sunset eh? Wassamatta, afraid of the dark? :} :E

Capn Bloggs 25th August 2007 10:35

Planetarium says this about the sunset time at London today:
At 0ft: 1903
At FL350: 1925
At FL490: 1929
:ok:

Gulfstreamaviator 25th August 2007 10:42

Blogs U is de mon
 
Simple question simple answer.

Thanks..

glf

vapilot2004 25th August 2007 12:12

Sorry for the slightly off-tanget post.....
 
I've yet fly at FL490 during any time of the day or night. :p




Back to sunsets:
Has anyone witnessed a flash of green?

forget 25th August 2007 14:15

Kuching Yacht Club. Only place, at ground level, it happens --
- so I'm told. Doubt that. :confused:

vapilot2004 25th August 2007 14:41

Heard the same is possible from some Florida and a few Oz and other Oceana locales.

However, I have yet to meet a witness , Forget.


:cool:

forget 25th August 2007 15:06


However, I have yet to meet a witness ....
Me :ok: Kuching. What you need, apparently, is a very clear atmosphere between the horizon and the sun, a very calm sea and, of course sun-set. For a split second the declining sun shines at you through a layer of sea water. Bingo! Green flash :ok:

fantom 25th August 2007 15:27

In-flight contest.

For east-bound pilots in the middle of the night, try to work out the time the sun will be seen to rise (by you) taking into account Alt; Lat; time of year and anything else you consider appropriate.

Not as easy as you might think. (At least, I can't do it).

Itswindyout 25th August 2007 17:34

only 490
 
limited to 490 due to cosmic radiation.

windy

FREDAcheck 25th August 2007 22:49

As suggested above, to be pedantic the difference between sunset at sea level and at altitude depends on latitude as well as altitude.

At FL400 (ish) it's nearly 30 mins after sea level at London latitude, but at the equator it's less than 10 minutes. This is because at the equator the sun takes a nose-dive to the horizon, but at higher latitudes it takes a more glancing angle, and takes longer to sink (hence why twilight is much longer at high latitudes), but you probably know that.

PantLoad 26th August 2007 00:37

What a beautiful sight!!!
 
I used to really enjoy watching the sunset from high altitudes. (The highest I've ever been is FL450...back years ago.)

PantLoad

galaxy flyer 26th August 2007 01:05

Capn Bloggs

What site did you get those times from? I have often wondered the same thing

GF

waav8r 26th August 2007 05:41

Green Flash - yessirree! Saw it several times in the late summer in Antarctica. As stated previously - requirement is very clear skies (no problemos there at the bottom of the world) and very still seas (a rarity in Antarctica, but easily replaced by sheet of seaice). Quite spectacular, as is the sunpillar sometimes abserved AFTER the sun has disappeared completely under the horizon.

Capn Bloggs 26th August 2007 05:52

GF,

"Planetarium" is a program on my Palm Pilot. :ok:

http://www.aho.ch/pilotplanets/

At Singapore (about1°N) tonight:

Sea Level: 1911
FL350: 1924
FL490: 1927


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