NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Wharton & Field's Hydrographical Surveying
From: Frank Reed CT
Date: 2004 May 10, 16:12 EDT
From: Frank Reed CT
Date: 2004 May 10, 16:12 EDT
Wolfgang K wrote:
"Contrary to what Fred H suggests radio time signals were not the final nail in the coffin of lunars."
Actually, I was the one who used the expression "final nail in the coffin" and noted that they were "effectively dead" for half a century before that. The rapid rise in the use of wireless communications is widely cited as a major reason why lunars were at long last dropped from the almanacs in the early 20th century.
And:
" How could they: lunars were dropped from the US Nautical Almanac in 1912, whereas the US Navy station radio time signal did not come on the air until February 1913"
There were other official wireless time signals on the air a few years earlier (Canada in 1909?), but perhaps the problem is that you're thinking exclusively in terms of an official government-sanctioned time signal. Before the arrival of radio, if you lost GMT at sea, you had few options. You could hope to encounter another ship and ask them for GMT, you could sail towards a safe shore and get GMT from the longitude of an established point of land (and a time sight) or by speaking to someone on land, OR you could shoot a lunar. After the arrival of radio during the first decade of the twentieth century, everything changed. Ships were no longer limited to the narrow scope of their visible horizon. With a wireless set, you could call out to any ship at sea, hundreds of miles away in daylight or thousands of miles away at night and ask, "What is GMT right now?" Lunars after this were relegated to the role of historical curiosity, challenging navigational entertainment, or apocalyptic backup. And they are still all of these things today, but radio in the early 20th century was the invention that finished off their last pretense to practical value. That was the "final nail in the coffin".
And:
"and how many ships were equipped to receive these signals?"
That depends very sensitively on the year you choose. Wireless was such a dramatic advance that the number of ships equipped with radio at least doubled annually for a period around 1910. Radio was ubiquitous on commercial and naval vessels within just a few short years.
And Wolfgang wrote:
"By that time Lunars had long been buried by the advent of cheaper chronometers and easier sight reduction methods – especially the St.Hilaire intercept method."
Cheap chronometers were certainly the main factor, and there were very few reasons to shoot lunars after 1850 or so, since you could more easily purchase backup chronometers than spend time and money on lunars. But professional navigators still learned them, grudgingly, up until the early years of the twentieth century as part of their advanced course work. There were occasional cases where lunars were used in the latter half of the 19th century including the famous sight taken by Joshua Slocum out in the eastern Pacific one sunny afternoon in the 1890s. So were they dead by 1850? Dead by 1890? Dead and buried by 1912?? Of course, one can quibble over "dead" versus "dead and buried", but I hope we don't have to! <g>
By the way, the St. Hilaire method is not really relevant to the decline and fall of lunars. If St. Hilaire had been developed and become popular, for example, in the 1840s, right after the Sumner experiment, you would still have found navigators shooting lunars to check their chronometers as there was no component of the St.Hilaire method that could replace lunars. It is true though that after the St. Hilaire method and its "tabular" cousins became standard in the early 20th century, the older sights like lunars seemed even more alien and exotic for practical navigators.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
"Contrary to what Fred H suggests radio time signals were not the final nail in the coffin of lunars."
Actually, I was the one who used the expression "final nail in the coffin" and noted that they were "effectively dead" for half a century before that. The rapid rise in the use of wireless communications is widely cited as a major reason why lunars were at long last dropped from the almanacs in the early 20th century.
And:
" How could they: lunars were dropped from the US Nautical Almanac in 1912, whereas the US Navy station radio time signal did not come on the air until February 1913"
There were other official wireless time signals on the air a few years earlier (Canada in 1909?), but perhaps the problem is that you're thinking exclusively in terms of an official government-sanctioned time signal. Before the arrival of radio, if you lost GMT at sea, you had few options. You could hope to encounter another ship and ask them for GMT, you could sail towards a safe shore and get GMT from the longitude of an established point of land (and a time sight) or by speaking to someone on land, OR you could shoot a lunar. After the arrival of radio during the first decade of the twentieth century, everything changed. Ships were no longer limited to the narrow scope of their visible horizon. With a wireless set, you could call out to any ship at sea, hundreds of miles away in daylight or thousands of miles away at night and ask, "What is GMT right now?" Lunars after this were relegated to the role of historical curiosity, challenging navigational entertainment, or apocalyptic backup. And they are still all of these things today, but radio in the early 20th century was the invention that finished off their last pretense to practical value. That was the "final nail in the coffin".
And:
"and how many ships were equipped to receive these signals?"
That depends very sensitively on the year you choose. Wireless was such a dramatic advance that the number of ships equipped with radio at least doubled annually for a period around 1910. Radio was ubiquitous on commercial and naval vessels within just a few short years.
And Wolfgang wrote:
"By that time Lunars had long been buried by the advent of cheaper chronometers and easier sight reduction methods – especially the St.Hilaire intercept method."
Cheap chronometers were certainly the main factor, and there were very few reasons to shoot lunars after 1850 or so, since you could more easily purchase backup chronometers than spend time and money on lunars. But professional navigators still learned them, grudgingly, up until the early years of the twentieth century as part of their advanced course work. There were occasional cases where lunars were used in the latter half of the 19th century including the famous sight taken by Joshua Slocum out in the eastern Pacific one sunny afternoon in the 1890s. So were they dead by 1850? Dead by 1890? Dead and buried by 1912?? Of course, one can quibble over "dead" versus "dead and buried", but I hope we don't have to! <g>
By the way, the St. Hilaire method is not really relevant to the decline and fall of lunars. If St. Hilaire had been developed and become popular, for example, in the 1840s, right after the Sumner experiment, you would still have found navigators shooting lunars to check their chronometers as there was no component of the St.Hilaire method that could replace lunars. It is true though that after the St. Hilaire method and its "tabular" cousins became standard in the early 20th century, the older sights like lunars seemed even more alien and exotic for practical navigators.
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
