> Being 1 minute off in time throws off distance by 15 nautical miles
I'm surprised that the accuracy of a hand-held sextant used while standing on a rolling/pitching deck is good enough for that to matter very much.
I'm surprised that the accuracy of a hand-held sextant used while standing on a rolling/pitching deck is good enough for that to matter very much.
https://www.ion.org/Museum/item_view.cfm?cid=2&scid=14&iid=2...
One thing that helps with a pitching deck is that the horizon and object remain the same angle. Like a camera following race car, the objects move together.
Life and death at times:
> The Scilly naval disaster of 1707 was the loss of four warships of a Royal Navy fleet off the Isles of Scilly in severe weather on 22 October 1707.[a] Between 1,400 and 2,000 sailors lost their lives aboard the wrecked vessels, making the incident one of the worst maritime disasters in British naval history.[2] The disaster has been attributed to a combination of factors, including the navigators' inability to accurately calculate their positions, errors in the available charts and pilot books, and inadequate compasses.[3]
* https://en.wikipedia.org/wiki/Scilly_naval_disaster_of_1707
When you're trying to find a tiny speck of an island (Pitcairn, Saint Helena, etc) in the middle of an ocean it's also important.
Sextants have a bit of magnification (usually 4x, but sometimes 7x or higher). Higher mag allows for better accuracy at the cost of more shaking of the view.
Basic explanation:
<https://virginflightdeck.blogspot.com/2010_09_01_archive.htm...>
(Something of a stealth favourite amongst HN commenters: <https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...>)
And not the only plane to make use of this option: <https://news.ycombinator.com/item?id=9549245>