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, 17:07 -0400
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
----------------------------------------------------------------
