Sunset at FL490
Joined: Jul 1999
Posts: 3,040
Likes: 0
From: 58-33N. 00-18W. Peterborough UK
However, I have yet to meet a witness ....
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
Dog Tired
Joined: Oct 2001
Posts: 1,686
Likes: 2
From: uk
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).
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).
Last edited by fantom; 25th August 2007 at 15:41.
Joined: Jun 2003
Posts: 407
Likes: 9
From: UK
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.
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.
Joined: May 2001
Posts: 52
Likes: 0
From: Australia
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.
Joined: Mar 2002
Aviation Qualifications: ATPL
Posts: 9,226
Likes: 995
From: Seat 1A
GF,
"Planetarium" is a program on my Palm Pilot.
http://www.aho.ch/pilotplanets/
At Singapore (about1°N) tonight:
Sea Level: 1911
FL350: 1924
FL490: 1927
"Planetarium" is a program on my Palm Pilot.
http://www.aho.ch/pilotplanets/
At Singapore (about1°N) tonight:
Sea Level: 1911
FL350: 1924
FL490: 1927
