NavList:

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.

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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

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