NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: John Huth
Date: 2013 May 6, 20:13 -0400
We pilots have the god like ability to make the sun rise in the west! We sit in the plane with the engine running at the end of the runway and wait until the sun sets. We then take off and climb steeply and watch the sun rise in the west!
gl
--- On Mon, 5/6/13, John H <apacherunner---com> wrote:
From: John H <apacherunner---com>Date: Monday, May 6, 2013, 2:13 PM
Subject: [NavList] Re: Sunrise - the Positive Side
To: garylapook---netThanks for Falconer's poem. That's wonderful! I really enjoy doing sunrise and sunset observations - it makes me feel connected to history, and I also like to think about all the oddities of refraction.I'll stay away from the Earhart stuff, but here's cute trick: if you're at a beach or very close to sea level near sunset - lie down on the ground. When you see the upper limb just vanish, jump up, and you'll regain the upper limb for a few seconds due to dip angle changes. I suppose you could try to calculate the radius of the earth using this, but my attempts only got me to within factors of 3-5 or so, but that's refraction for ya.On Mon, May 6, 2013 at 10:03 AM, Don Seltzer <timoneer---com> wrote:
Jeremy C wrote: I tend to agree with Byron. It's easiest to observe and compute the amplitude on the celestial horizon.
In my standing orders, I have it stated that azimuths and amplitudes are to be shot every watch when the opportunity presents itself.-------
I think it worthwhile to repost William Falconer's 18th century description of the routine:'The dim horizon lowering vapours shroud,
And blot the sun yet struggling in the cloud;
Thro' the wide atmosphere condensed with haze,
His glaring orb emits a sanguine blaze.
The pilots now their azimuth attend,
On which all courses, duly form'd, depend:
The compass placed to catch the rising ray,
The quadrant's shadows studious they survey;
Along the arch the gradual index slides,
While Phoebus down the vertic-circle glides;
Now seen on ocean's utmost verge to swim,
He sweeps it vibrant with his nether limb.
Thus height, and polar distance are obtain'd,
Then latitude, and declination, gain'd;
In chiliads next the analogy is sought,
And on sinical triangle wrought:
By this magnetic variance is explored,
Just angles known, and polar truth restored.'from The Shipwreck
Don Seltzer
----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
----------------------------------------------------------------