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Tried to explain this back in November but had it deleted by someone who simply proclaimed that they couldn't understand it. Hopefully this works better!
Mike 11:48, 8 February 2007 (UTC)
PPS. Thanks for the article, I remember a TV program on "Longitude", where it simple asked the audience to laugh at another approach to working out position. Now that I understand the technique it explains not only what the other approach was, but a lot of history such as why they built observatories on remote islands - it was to create a realiable and accurate local fixed reference point from which they could then work out the exact position of other local points using much less accurate equipment so long as it was calibrated to the known reference point!
I presume that is also why they were so interested in solar eclipses. I assume they could calculate the time of the eclipse much more accurately than their time pieces could measure time, therefore using an eclipse, they would have a very accurate local time reference from which, using the moon's position they could then very accurately determine the longitude of the observatory .... it all makes sense because of this article! Mike 12:11, 8 February 2007 (UTC)
After being a little agrieved about having my original article being removed, I realised that it was too complicated. Sometimes criticism is the best compliment. The result of the many contributions since then has been a great improvement to the article.
Using the method of lunar distances to find longitude and time is tricky business. There are a lot of corrections applied to get the required accuracy.
Here are some of the esoterica:
In my updates to this page, I am relying on the expertise of several individuals knowledgeable in the current (yes, current!) and historical practice of using lunar distances for longitude. I expect a lot (for this article) of activity in the next month or so, and hope to get all the facts properly cited. -- SV Resolution( Talk) 12:33, 31 July 2007 (UTC)
When exactly did HMNAO stop publishing the lunars? 1852 or 1906? http://www.math.uu.nl/people/wepster/ldtab.html says that radio signals were used for setting chronometers at sea by 1905, the last year the HMNAO published lunars. -- SV Resolution( Talk) 04:36, 3 August 2007 (UTC)
For correcting the dates of the Norie references. I cannot believe I didn't spot that mistake. -- SV Resolution( Talk) 18:10, 6 August 2007 (UTC)
In the method section, The passage which used to read ( 152803345):
Knowing Greenwich time and local time, the navigator can work out longitude.<ref name="Norie 1828 pg 222"/>
now reads ( 153036652):
Knowing Greenwich time and the altitudes of the moon and the other body, the navigator can apply the [[intercept method]] to find his latitude and longitude. Alternately, the navigator can [[longitude by chronometer|first determine local time, and then longitude]].<ref name="Norie 1828 pg 222"/>
Note the reference to longitude by chronometer. If you've got the chronometer, why bother with lunars?
As has been noted in the Google NavList group, the intercept method was not used during the "golden age of lunars". Further, the almanacs originally only gave the moon's GHA and dec at noon and midnight, GMT, so the moon could not originally have been used in the intercept method, in any case. (I do hope the experts at NavList can provide helpful references for this information, so we can include it in the article).
I propose going back to the simpler statement, in order to avoid having to explain that, in the age before chronometers, navigators actually didn't do it that way.
I think that, in the history section, it would be appropriate to list the different approaches taken at different times. Up to and including the present, of course. I don't feel qualified to write this history myself, but I do feel strongly that the confusing statement in Method ought to be undone.
-- SV Resolution( Talk) 00:53, 23 August 2007 (UTC)
I don't mind removing the reference to the intercept method, which came later.
The reference to longitude by chronometer was really to the concept that knowing the (Greenwich) time and one altitude lets you calculate the longitude. If you have a chronometer it can tell you the time. The lunar is another source of time. That's why I changed the wording of the reference. Jrvz 00:32, 24 August 2007 (UTC)
I think I know what you were getting at. I made a reference to Celestial Navigation, and separated much of your detail from the summary of the method. At what point do you make the atmospheric corrections? Before parallax, or do you plug it all into the same complicated formula? -- 72.94.157.91 01:08, 24 August 2007 (UTC)
The diagram appears to show the constellation Orion (vaguely), but the Moon cannot be in that position relative to Orion. Setting that aside, since the resemblance to Orion is rather weak, you'll notice that the Moon is a crescent. That means that the Sun would be in the sky to the right of the Moon in a direction perpendicular to the points on the end of the crescent. That would be above the horizon as the diagram is drawn. In other words, the Moon can only appear as a crescent in that orientation in daytime and so the stars would be invisible. Other than that, it's a nice artistic rendering. I like the boat! 24.136.6.69 02:56, 4 September 2007 (UTC)
In the first sentence of the Errors section, someone wants a citation for the statement that a lunar distance changes about 1/2 degree per hour. Is that really necessary? It's well known that the Moon makes an orbit in about 30 days. That's 12 degrees per day, or 1/2 degree per hour. I don't think a citation is necessary. Paul Hirose 23:50, 15 September 2007 (UTC)
I agree. On the other hand, it is easy to find such citations, and that's an opportunity to link another book (or web site) on navigation which could only benefit the readers of this page. 24.136.6.69 23:50, 20 September 2007 (UTC)
In a few recent edits, it's been stated that radio time signals "replaced" the chronomter or superceded other methods of getting GMT. This is misleading. Radio time signals were used to verify the chronometers. Also, it's worth noting that vessels at sea with radio could compare values for GMT even before official time signal broadcasts. This was nothing more than an extension of the old system of "speaking other ships". Before radio, it was quite common for two vessels passing each other at sea to signal their longitudes (or equivalently GMT). Radio extended the range at which this could be done from a few hundred yards to thousands of miles. —Preceding unsigned comment added by 24.136.6.69 ( talk) 00:44, 18 October 2007 (UTC)
Note that there was some significant additional discussion leading to edits of this Wikipedia page on the Navigation List (traditional navigation discussion group). Most of the direct discussion took place in August, 2007. Visit the group's archive [1] and search on Wikipedia. There are also numerous discussions of lunar distances generally in this archive. Membership is open to anyone. 24.136.6.69 22:52, 22 October 2007 (UTC)
Due to the redundant and sometimes contradictory information in various articles on navigation history, I amalgamated all the history sections into a single History of longitude article.
All the articles, including this one, have been changed to refer to that article instead of trying to rehash the same information.
Please restrict information in this article to be specific to the use of the method. -- Michael Daly 18:27, 30 October 2007 (UTC)
I think it was a mistake to blow away the whole history section. A "typical" encylopedia article would include history specific to the topic. I agree that the earlier history section was a bit of a mess, but I think it would be best to restore appropriate material to this article. I'll start a new section sometime soon. 24.136.6.69 ( talk) 03:42, 28 November 2007 (UTC)
Well, I certainly understand your concerns. Nonetheless, the article is better with a History section. I took the previous one, trimmed out a lot of extraneous material, cleaned up some language, and re-instated it. 24.136.6.69 ( talk) 12:57, 28 November 2007 (UTC)
MichaelDaly: please refrain from summary deletion of material you do not like. It is poor behavior on Wikipedia.
To your points: 1) you claim that the Shovell disaster was not connected to the story, citing May. The article by W.E. May is interesting, of course, but it in no way constitutes proof of the revisionist hypothesis that this was a latitude error rather than a longitude error. I can quote a half-dozen sources that DO agree this was an important longitude story. May HIMSELF shows a spread of some 300 minutes of arc in relative longitude among the vessels whose logbooks survived and only 20 minutes of arc in relative latitude error. He carefully masks the equally large error in absolute longitude error with his diagram displaying the vessel tracks as if the absolute longitude has been determined. Note also that one of May's principal points in his article was that the latitude of the Scillies was not known. And yet this very error which he considers so important was so widely known that it had even been written up in the Transactions of the Royal Society. And finally let's remember that Wikipedia is about citations --not personal opinions. 2) You say that Mayer's work was mid-century rather than "latter half". That's a minor point, but sure, change it to read "mid-century". No problem. Your claim that Mayer's tables were not the key is seriously misleading. The only significant contribution from Flamsteed to all of this were the exact positions of the nine/ten lunars stars, which were widely known by this period in any case. Halley has no significant contribution. 3) The minor redundancy in the text is no reason to delete that section. Frequently, good prose has some degree of redundancy. That's how points are made clear. 4) The peripheral reference to chronometers explains something very specific about the end of the lunars era. Lunars were NOT killed off by radio time signals, as you have written elsewhere --they were long over and done with by then. They were killed off by cheap chronometers by c.1850/55. Only the end of the highly conservative continued publications of the tables in the almanacs coincides with the proliferation of radio time signals. 24.136.6.69 01:30, 1 December 2007 (UTC)
I think the subject of how to 1) determine local time and 2) how to get from local time vs. GMT to longitude should be discussed more explicitly. Determining local time might warrant its own entry.-- icedtea1954 ( talk) 01:26, 23 January 2008 (UTC)
When computing the difference between GMT and local time, one has to take the Equation of time into account. It amounts up to a quarter of an hour! Rgds -- Boobarkee ( talk) 12:39, 18 August 2009 (UTC)
I`m in search for data on the accuracy of astronomic derived longitude (land based, I assume lunar eclipse or occulation) before the time of telescopes and marine dead reckoning accuracy (all times, all ships) -- Portolanero ( talk) 14:36, 16 June 2011 (UTC)
In Practice ... Step One – Preliminaries
... other body (see any nautical almanac from 1767 to c.1900).[citation needed]
To my way of thinking, 'see any nautical almanac' is all the citation needed, considering that a number of them are available. That fact ought to be known to most readers of this article. 97.112.224.68 ( talk) 19:55, 30 September 2012 (UTC)Mac Hayes
... Also in Step One – Preliminaries
...Since the Moon's apparent size varies with its varying distance from the Earth.[citation needed]
Is a citation needed for such an obvious statement? Does someone wonder if perhaps some believe that the moon stays the same apparent size despite its varying distance from earth and therefore the statement requires proof? This too is a fact that ought to be know to anyone with a rudimentary knowledge of astronomy. — Preceding unsigned comment added by 67.40.212.11 ( talk) 07:21, 9 April 2014 (UTC)
I read somewhere that the cost of sextants could exceed the cost of chronometers, and if I find it again, will post the reference here. -- Pawyilee ( talk) 10:28, 7 December 2012 (UTC)
This "fun fact" observable by most quickly, helps explain sun moon angle (and indirectly, how celestial plane aziumuth intersection is a possible basis for releasing observed angle charts, error not incl)
Using sunclock(1) software animated at 1 day intervals one can easily see the sun yearly period rise and fall between the tropic lines of cancer and capricorn. The moon does the same every 27 days.
At 12/1 pm every 27 days they always intersect, have roughly the same latitude and longitude ! (roughly) This means if it is 1/2 way between summer and winter (sun is on equator) then 1/2 between 27 days, and stand at (0,80) deg. the sun and moon are the same place in the sky directly overhead, every 27 days.
An observer at different (lat,lon) can get a rough position fix with a single (1pm) sighting. The sun gives rough latitude just by angle (due to time of year) and any angle between sun an moon observed is due to now known latitude difference and longitude difference (ie, at 80 deg). Every 27 days. Elsewise (between days) one would need a chart for time and day and do some extra work.
The sun-moon angle published in nav. books may refer to something else that i'm unsure of i don't have one.
Similarly one can use Orion belt for azimuth being overhead directly at night, but the angles are so slight it is too difficult without expensive equipment.
This little anecdote is interesting to some, but provides nothing of significance to the topic of the lunar distance method. Can someone suggest a valid reason for its inclusion (as opposed to any number of other anecdotes about lunars)? 99.245.230.104 ( talk) 08:57, 23 June 2014 (UTC)
I've removed mention of it for the time being since it was uncited, unmentioned by Britannica, and centuries off the first use listed here, but William Baffin's page formerly claimed he had practiced lunar distance. Kindly restore it with citation there and add it here if that's an accurate claim. Worth noting the error if it turns out to have been one. — LlywelynII 12:57, 4 December 2015 (UTC)
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The article mentions Greenwich mean time 18 times, out of which 15 are not titles of references or links to Greenwich-specific entities. So as I think that the English are not the only ocean-faring people, lunar reckoning was done also before the adoption of GMT as the international standard time (actually primarily so), and I further do not think that "Greenwich" is widely used as a synonym for "national standard meridian", I would suggest to change the relevant instances to "reference time". Note that the question whether the English Wikipedia is to be seen as the Wikipedia of the English-speaking peoples or rather as the main international Wikipedia does not apply here, as probably also for British subjects the way how other nations calculated their longitude is relevant (and even then there would also be the US-Americans, or did they, and the Spanish, Dutch and French, really use almanacs with reference to GMT?). Seattle Jörg ( talk) 06:51, 22 October 2018 (UTC)
Following this post by Frank Reed on NavList ( http://fer3.com/arc/m2.aspx/Navigation-articles-Wikipedia-FrankReed-aug-2019-g45682), and the recent workshop on Lunars at Mystic Seaport I suggest we have an improvement drive for this article. Billlion ( talk) 22:21, 28 August 2019 (UTC)
![]() | This article is rated C-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
|
Tried to explain this back in November but had it deleted by someone who simply proclaimed that they couldn't understand it. Hopefully this works better!
Mike 11:48, 8 February 2007 (UTC)
PPS. Thanks for the article, I remember a TV program on "Longitude", where it simple asked the audience to laugh at another approach to working out position. Now that I understand the technique it explains not only what the other approach was, but a lot of history such as why they built observatories on remote islands - it was to create a realiable and accurate local fixed reference point from which they could then work out the exact position of other local points using much less accurate equipment so long as it was calibrated to the known reference point!
I presume that is also why they were so interested in solar eclipses. I assume they could calculate the time of the eclipse much more accurately than their time pieces could measure time, therefore using an eclipse, they would have a very accurate local time reference from which, using the moon's position they could then very accurately determine the longitude of the observatory .... it all makes sense because of this article! Mike 12:11, 8 February 2007 (UTC)
After being a little agrieved about having my original article being removed, I realised that it was too complicated. Sometimes criticism is the best compliment. The result of the many contributions since then has been a great improvement to the article.
Using the method of lunar distances to find longitude and time is tricky business. There are a lot of corrections applied to get the required accuracy.
Here are some of the esoterica:
In my updates to this page, I am relying on the expertise of several individuals knowledgeable in the current (yes, current!) and historical practice of using lunar distances for longitude. I expect a lot (for this article) of activity in the next month or so, and hope to get all the facts properly cited. -- SV Resolution( Talk) 12:33, 31 July 2007 (UTC)
When exactly did HMNAO stop publishing the lunars? 1852 or 1906? http://www.math.uu.nl/people/wepster/ldtab.html says that radio signals were used for setting chronometers at sea by 1905, the last year the HMNAO published lunars. -- SV Resolution( Talk) 04:36, 3 August 2007 (UTC)
For correcting the dates of the Norie references. I cannot believe I didn't spot that mistake. -- SV Resolution( Talk) 18:10, 6 August 2007 (UTC)
In the method section, The passage which used to read ( 152803345):
Knowing Greenwich time and local time, the navigator can work out longitude.<ref name="Norie 1828 pg 222"/>
now reads ( 153036652):
Knowing Greenwich time and the altitudes of the moon and the other body, the navigator can apply the [[intercept method]] to find his latitude and longitude. Alternately, the navigator can [[longitude by chronometer|first determine local time, and then longitude]].<ref name="Norie 1828 pg 222"/>
Note the reference to longitude by chronometer. If you've got the chronometer, why bother with lunars?
As has been noted in the Google NavList group, the intercept method was not used during the "golden age of lunars". Further, the almanacs originally only gave the moon's GHA and dec at noon and midnight, GMT, so the moon could not originally have been used in the intercept method, in any case. (I do hope the experts at NavList can provide helpful references for this information, so we can include it in the article).
I propose going back to the simpler statement, in order to avoid having to explain that, in the age before chronometers, navigators actually didn't do it that way.
I think that, in the history section, it would be appropriate to list the different approaches taken at different times. Up to and including the present, of course. I don't feel qualified to write this history myself, but I do feel strongly that the confusing statement in Method ought to be undone.
-- SV Resolution( Talk) 00:53, 23 August 2007 (UTC)
I don't mind removing the reference to the intercept method, which came later.
The reference to longitude by chronometer was really to the concept that knowing the (Greenwich) time and one altitude lets you calculate the longitude. If you have a chronometer it can tell you the time. The lunar is another source of time. That's why I changed the wording of the reference. Jrvz 00:32, 24 August 2007 (UTC)
I think I know what you were getting at. I made a reference to Celestial Navigation, and separated much of your detail from the summary of the method. At what point do you make the atmospheric corrections? Before parallax, or do you plug it all into the same complicated formula? -- 72.94.157.91 01:08, 24 August 2007 (UTC)
The diagram appears to show the constellation Orion (vaguely), but the Moon cannot be in that position relative to Orion. Setting that aside, since the resemblance to Orion is rather weak, you'll notice that the Moon is a crescent. That means that the Sun would be in the sky to the right of the Moon in a direction perpendicular to the points on the end of the crescent. That would be above the horizon as the diagram is drawn. In other words, the Moon can only appear as a crescent in that orientation in daytime and so the stars would be invisible. Other than that, it's a nice artistic rendering. I like the boat! 24.136.6.69 02:56, 4 September 2007 (UTC)
In the first sentence of the Errors section, someone wants a citation for the statement that a lunar distance changes about 1/2 degree per hour. Is that really necessary? It's well known that the Moon makes an orbit in about 30 days. That's 12 degrees per day, or 1/2 degree per hour. I don't think a citation is necessary. Paul Hirose 23:50, 15 September 2007 (UTC)
I agree. On the other hand, it is easy to find such citations, and that's an opportunity to link another book (or web site) on navigation which could only benefit the readers of this page. 24.136.6.69 23:50, 20 September 2007 (UTC)
In a few recent edits, it's been stated that radio time signals "replaced" the chronomter or superceded other methods of getting GMT. This is misleading. Radio time signals were used to verify the chronometers. Also, it's worth noting that vessels at sea with radio could compare values for GMT even before official time signal broadcasts. This was nothing more than an extension of the old system of "speaking other ships". Before radio, it was quite common for two vessels passing each other at sea to signal their longitudes (or equivalently GMT). Radio extended the range at which this could be done from a few hundred yards to thousands of miles. —Preceding unsigned comment added by 24.136.6.69 ( talk) 00:44, 18 October 2007 (UTC)
Note that there was some significant additional discussion leading to edits of this Wikipedia page on the Navigation List (traditional navigation discussion group). Most of the direct discussion took place in August, 2007. Visit the group's archive [1] and search on Wikipedia. There are also numerous discussions of lunar distances generally in this archive. Membership is open to anyone. 24.136.6.69 22:52, 22 October 2007 (UTC)
Due to the redundant and sometimes contradictory information in various articles on navigation history, I amalgamated all the history sections into a single History of longitude article.
All the articles, including this one, have been changed to refer to that article instead of trying to rehash the same information.
Please restrict information in this article to be specific to the use of the method. -- Michael Daly 18:27, 30 October 2007 (UTC)
I think it was a mistake to blow away the whole history section. A "typical" encylopedia article would include history specific to the topic. I agree that the earlier history section was a bit of a mess, but I think it would be best to restore appropriate material to this article. I'll start a new section sometime soon. 24.136.6.69 ( talk) 03:42, 28 November 2007 (UTC)
Well, I certainly understand your concerns. Nonetheless, the article is better with a History section. I took the previous one, trimmed out a lot of extraneous material, cleaned up some language, and re-instated it. 24.136.6.69 ( talk) 12:57, 28 November 2007 (UTC)
MichaelDaly: please refrain from summary deletion of material you do not like. It is poor behavior on Wikipedia.
To your points: 1) you claim that the Shovell disaster was not connected to the story, citing May. The article by W.E. May is interesting, of course, but it in no way constitutes proof of the revisionist hypothesis that this was a latitude error rather than a longitude error. I can quote a half-dozen sources that DO agree this was an important longitude story. May HIMSELF shows a spread of some 300 minutes of arc in relative longitude among the vessels whose logbooks survived and only 20 minutes of arc in relative latitude error. He carefully masks the equally large error in absolute longitude error with his diagram displaying the vessel tracks as if the absolute longitude has been determined. Note also that one of May's principal points in his article was that the latitude of the Scillies was not known. And yet this very error which he considers so important was so widely known that it had even been written up in the Transactions of the Royal Society. And finally let's remember that Wikipedia is about citations --not personal opinions. 2) You say that Mayer's work was mid-century rather than "latter half". That's a minor point, but sure, change it to read "mid-century". No problem. Your claim that Mayer's tables were not the key is seriously misleading. The only significant contribution from Flamsteed to all of this were the exact positions of the nine/ten lunars stars, which were widely known by this period in any case. Halley has no significant contribution. 3) The minor redundancy in the text is no reason to delete that section. Frequently, good prose has some degree of redundancy. That's how points are made clear. 4) The peripheral reference to chronometers explains something very specific about the end of the lunars era. Lunars were NOT killed off by radio time signals, as you have written elsewhere --they were long over and done with by then. They were killed off by cheap chronometers by c.1850/55. Only the end of the highly conservative continued publications of the tables in the almanacs coincides with the proliferation of radio time signals. 24.136.6.69 01:30, 1 December 2007 (UTC)
I think the subject of how to 1) determine local time and 2) how to get from local time vs. GMT to longitude should be discussed more explicitly. Determining local time might warrant its own entry.-- icedtea1954 ( talk) 01:26, 23 January 2008 (UTC)
When computing the difference between GMT and local time, one has to take the Equation of time into account. It amounts up to a quarter of an hour! Rgds -- Boobarkee ( talk) 12:39, 18 August 2009 (UTC)
I`m in search for data on the accuracy of astronomic derived longitude (land based, I assume lunar eclipse or occulation) before the time of telescopes and marine dead reckoning accuracy (all times, all ships) -- Portolanero ( talk) 14:36, 16 June 2011 (UTC)
In Practice ... Step One – Preliminaries
... other body (see any nautical almanac from 1767 to c.1900).[citation needed]
To my way of thinking, 'see any nautical almanac' is all the citation needed, considering that a number of them are available. That fact ought to be known to most readers of this article. 97.112.224.68 ( talk) 19:55, 30 September 2012 (UTC)Mac Hayes
... Also in Step One – Preliminaries
...Since the Moon's apparent size varies with its varying distance from the Earth.[citation needed]
Is a citation needed for such an obvious statement? Does someone wonder if perhaps some believe that the moon stays the same apparent size despite its varying distance from earth and therefore the statement requires proof? This too is a fact that ought to be know to anyone with a rudimentary knowledge of astronomy. — Preceding unsigned comment added by 67.40.212.11 ( talk) 07:21, 9 April 2014 (UTC)
I read somewhere that the cost of sextants could exceed the cost of chronometers, and if I find it again, will post the reference here. -- Pawyilee ( talk) 10:28, 7 December 2012 (UTC)
This "fun fact" observable by most quickly, helps explain sun moon angle (and indirectly, how celestial plane aziumuth intersection is a possible basis for releasing observed angle charts, error not incl)
Using sunclock(1) software animated at 1 day intervals one can easily see the sun yearly period rise and fall between the tropic lines of cancer and capricorn. The moon does the same every 27 days.
At 12/1 pm every 27 days they always intersect, have roughly the same latitude and longitude ! (roughly) This means if it is 1/2 way between summer and winter (sun is on equator) then 1/2 between 27 days, and stand at (0,80) deg. the sun and moon are the same place in the sky directly overhead, every 27 days.
An observer at different (lat,lon) can get a rough position fix with a single (1pm) sighting. The sun gives rough latitude just by angle (due to time of year) and any angle between sun an moon observed is due to now known latitude difference and longitude difference (ie, at 80 deg). Every 27 days. Elsewise (between days) one would need a chart for time and day and do some extra work.
The sun-moon angle published in nav. books may refer to something else that i'm unsure of i don't have one.
Similarly one can use Orion belt for azimuth being overhead directly at night, but the angles are so slight it is too difficult without expensive equipment.
This little anecdote is interesting to some, but provides nothing of significance to the topic of the lunar distance method. Can someone suggest a valid reason for its inclusion (as opposed to any number of other anecdotes about lunars)? 99.245.230.104 ( talk) 08:57, 23 June 2014 (UTC)
I've removed mention of it for the time being since it was uncited, unmentioned by Britannica, and centuries off the first use listed here, but William Baffin's page formerly claimed he had practiced lunar distance. Kindly restore it with citation there and add it here if that's an accurate claim. Worth noting the error if it turns out to have been one. — LlywelynII 12:57, 4 December 2015 (UTC)
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The article mentions Greenwich mean time 18 times, out of which 15 are not titles of references or links to Greenwich-specific entities. So as I think that the English are not the only ocean-faring people, lunar reckoning was done also before the adoption of GMT as the international standard time (actually primarily so), and I further do not think that "Greenwich" is widely used as a synonym for "national standard meridian", I would suggest to change the relevant instances to "reference time". Note that the question whether the English Wikipedia is to be seen as the Wikipedia of the English-speaking peoples or rather as the main international Wikipedia does not apply here, as probably also for British subjects the way how other nations calculated their longitude is relevant (and even then there would also be the US-Americans, or did they, and the Spanish, Dutch and French, really use almanacs with reference to GMT?). Seattle Jörg ( talk) 06:51, 22 October 2018 (UTC)
Following this post by Frank Reed on NavList ( http://fer3.com/arc/m2.aspx/Navigation-articles-Wikipedia-FrankReed-aug-2019-g45682), and the recent workshop on Lunars at Mystic Seaport I suggest we have an improvement drive for this article. Billlion ( talk) 22:21, 28 August 2019 (UTC)