Moon Phases in The Lord of the Rings

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Phases of the Moon

As you perhaps noticed on the home page or in the archives, this site displays the phase of the moon for each day of the adventure in The Lord of the Rings. Since some readers will be curious how this site computes the phase of the moon, and others may even wish to do their own calculations, this page attempts to collect everything known about lunar phases in Tolkien's text.

The text of The Lord of the Rings usually offers only a partial description of the Moon — such as telling us that the Moon is shining without mentioning from which direction, or giving the time at which it sets without describing its phase. So we are fortunate that the shape, position, and schedule of the Moon are closely related, allowing us to frequently deduce some of its properties from others. The basic relationships are sketched in the following diagrams for those who might be unfamiliar with them:

Waxing
Crescent
Waxing
Gibbous
Full Waning
Gibbous
Waning
Crescent
waxing crescent moon waxing gibbous moon full moon waning gibbous moon waning crescent moon
  • Already in the western sky at sunset.
  • Sets before midnight.
  • Still in the eastern sky at sunset.
  • Passes overhead before midnight.
  • Sets before dawn.
  • Rises at sunset
  • Overhead at midnight
  • Sets at dawn
  • Rises before midnight.
  • Passes overhead after midnight.
  • In the western sky at dawn.
  • Rises after midnight.
  • Still in the eastern sky at dawn.

In case you find the terminology unfamiliar, the Moon is said to be waxing as it grows toward full, waning as it shrinks again afterwards, to be crescent when less than half full, and to be gibbous when more than half.

The Problem New Moon of February, S.R. 1419

There are many nights during the adventure, and indeed entire weeks and months, for which The Lord of the Rings gives no description of the moon. To display its phases, therefore, requires a general schedule or formula that gives the phase whether the text mentions the moon that night or not. Since the new and full moons in the narrative are separated by different lengths of time, much like the slightly irregular schedule of the real Moon, we cannot merely estimate the moon's phase using the average length of the lunar month and have the results match the text. It would therefore be helpful to find a modern schedule of new and full moons matching those in The Lord of the Rings upon which we could base our predictions.

Unfortunately, any attempt to correlate modern Moon phases with those in The Lord of the Rings fails because of the impossibly long interval between the New Moon of February, S.R. 1419 and the full moon that follows on March 8th. As the Company travel down the Anduin after leaving Lórien, we are told on February 22nd that:

At Aragorn's bidding they paddled now for long spells, and the banks went swiftly by. But they saw little of the country, for they journeyed mostly by night and twilight, resting by day, and lying as hidden as the land allowed. In this way the time passed without event until the seventh day.

The weather was still grey and overcast, with wind from the East, but as evening drew into night the sky away westward cleared, and pools of faint light, yellow and pale green, opened under the grey shores of cloud. There the white rind of the new Moon could be seen glimmering in the remote lakes. Sam looked at it and puckered his brows. 
(II.9)

We can empathize with Sam and his puckered brows! But while Sam himself is confused because he lost track of time amidst the immortal beauty of Lórien, we are confused because this crescent moon simply should not be visible yet.

Each month, the crescent moon first becomes visible one or two days after the moment at which the moon is new — the instant at which it is most completely dark and at the opposite end of its journey from full. But this means that the actual moment of new moon must have arrived more than a dozen hours before Sam saw its crescent above the lakes, putting the new moon far too early when compared with the subsequent full moon:

dates of phases of the moon
Phases of the moon for the beginning of S.R. 1419.

Even after making every possible concession, the schedule of moons presented in The Lord of the Rings remains impossible for the modern moon:

Since in modern times the period between new and full moon never exceeds 15 days, 15 hours, any modern schedule will still fall more than nine hours short of the sixteen-day interval required by the text. Though at least three wild theories seem available for explaining away the impossibility, each of them falls short:

The only remaining option is simply to accept, without the possibility of an internal explanation, that this particular New Moon of the Third Age fell at least one day early, and determine how to include this aberration in a general framework for computing moon phases.

Causes and Consequences

The impossible moon phases of S.R. 1419 are explained very simply if Tolkien was copying his moon phases out of an almanac for a real year, and mistakenly thought that almanacs use the phrase “new moon” in its colloquial English sense, meaning the date on which the new crescent moon appears. But almanacs in fact use “new moon” in its astronomical sense, to mean the moment when the moon is most dark. Through this mistake, Tolkien would have put a crescent moon in his narrative everywhere he really wanted the dark of the moon, and would thus have forced the actual new moons in Middle-earth to each be one or two days too early.

If one examines the very few dates which Tolkien could have counted as the first day of Shire year 1419 and gotten a pattern of full and new moons matching the full and crescent moons given in the narrative, one is immediately struck by the presence of Christmas 1941 in the list of dates:

For reference, the following table demonstrates how counting Christmas 1941 as the first day of Shire year 1419 would have given Tolkien precisely the moons required:

1942 AlmanacDate in S.R. 1419 Tolkien describes this moon:

January 2nd— Full January 8th As “full
January 16th— New January 22nd (not described)
February 1st— Full February 8th (not described)
February 15th— New February 22nd As the “white rind” Sam sees
March 3rd— Full March 8th As “full
March 16th— New March 21st As a new crescent*

*Since on the 24th they see a “waxing moon ... four nights old

To display the phase of the moon for this web site, the real moon phases of 1942 are combined with a correction that moves the moment of each new moon about a day and a half earlier. The effect of this correction upon the waxing and waning half-moons must be different: the waxing half-moon must remain in place so that the moon is still crescent when Frodo sees it on February 29th, but the waning half-moon must happen early for a crescent moon to be seen by Frodo on January 16th. The corrected phase we use is therefore:

moon phase adjustment equation

Lunar References in the Text

Here are all of the references to the actual appearance of the Moon in The Lord of the Rings (a list which ignores things like references to the Moon in poetry and song). References which create problems when trying to work out a realistic schedule of moon phases are highlighted and marked as “problematic”.

moon 66.2% full 1418 June 20
This was the night that the forces of Sauron attacked Osgiliath. At the Council of Elrond four months later, on October 25th, Boromir recalls that his men described the Nazgûl as “a dark shadow under the moon”.
moon 73.1% full 1418 September 18problematic
On this night Gandalf was rescued from his imprisonment atop the pinnacle of Orthanc, which Frodo dreams of eight nights later (on the evening of September 26th) at the house of Tom Bombadil. In his dream he sees “the young moon rising”, which presents two problems: first, that he should instead be seeing an old moon; and second, that a young moon would be setting rather than rising. We had better dismiss this observation as a disorientation produced by the dream. When he describes the dream at the Council of Elrond a month later, he only mentions the moonlight falling on Gandalf's hair, and the wizard, in his own retelling of the event, says merely that it was “a night of moon”.
moon 94.3% full 1418 September 24
When hiding beside the road from the Black Rider at dusk, Frodo sees that, “Above [the road] the stars were thick in the dim sky, but there was no moon.
moon 27.4% full 1418 October 4
At their camp the night before reaching the Weather Hills, the Hobbits and Strider see that, “The moon was waxing, and in the early night-hours a cold grey light lay on the land.
moon 34.3% full 1418 October 6
Just before their camp on Weathertop is attacked, the Hobbits see that above Strider “was a black starry sky. Suddenly a pale light appeared over the crown of Weathertop behind him. The waxing moon was climbing slowly above the hill that overshadowed them, and the stars above the hill-top faded. ... ‘Look!’ said Merry. ‘The Moon is rising: it must be getting late.’” They continue to see the Moon on subsequent evenings as they move south of the Road and make for the Last Bridge.
moon 49.5% full 1419 January 8
As Aragorn guides the Company of the Ring through Hollin toward the Redhorn Pass, the “Moon, now at the full, rose over the mountains, and cast a pale light in which the shadows of stones were black.” Before dawn we are told, consistent with this, that “the moon was low.
moon 67.1% full 1419 January 13
Just before the final attack of the Wargs against the Company, we are told that the “night was old, and westward the waning moon was setting, gleaming fitfully through the breaking clouds.
moon 70.8% full 1419 January 14problematic
Just before the outline of the West Gate of Moria appears on the cliff face, we are told that the “Moon now shone upon the grey face of the rock”, which can only have happened after midnight — and thus early on the 14th — since a waning moon cannot shine on a westward-facing cliff until it passes into the western sky after midnight. So the “Tale of Years” must be incorrect when it has the Company enter Moria before midnight on the 13th.
moon 74.6% full 1419 January 15
After the remaining Company emerge from Moria, Aragorn warns them that they will lack light this evening since “The Moon is almost spent, and it will be dark tonight”, and indeed when night falls we are told that, “There were many clear stars, but the fast-waning moon would not be seen till late.
moon 78.5% full 1419 January 16problematic
In the night, before dawn, Frodo wakes and hears Orcs moving past the flet on which he is sleeping, and sees that the “sickle Moon was gleaming dimly among the leaves”. This moon should really be exactly half-full, rather than sickle, eight days after the full moon.
moon 5.2% full 1419 February 22problematic
From the camp on the seventh evening after leaving Lórien, we are told that “the white rind of the new Moon could be seen glimmering in the remote lakes”, raising the problems discussed at length above.
moon 8.0% full 1419 February 23
On the eighth night from Lórien the “thin crescent of the Moon had fallen early into the pale sunset”, which confuses Sam because he lost track of time in Caras Galadon.
moon 16.0% full 1419 February 26
As Merry and Pippin were dragged away by the Orcs, the “waxing moon was riding in the West,” and it is described explicitly as “the slim moon ... already falling westward” and a soon afterwards we are told of “the last rays of the sickle moon.
moon 18.5% full 1419 February 27
As the Three Hunters pursue the Orcs who have captured Merry and Pippin, we are told that, “There in the still cool hour before dawn they rested for a brief space. The moon had long gone down before them, the stars glittered above them... .” Late in the day Aragorn decides that, “We will not walk in the dark ... If the Moon gave enough light, we would use it, but alas! he sets early and is yet young and pale.
moon 21.0% full 1419 February 28
When the Three Hunters halt again after sunset, “The young moon was glimmering in a misty sky”, and it is described explicitly as a “sickle moon.

Somewhat confusing is the description of this same Moon when it is sighted by Merry and Pippin from the Orc-camp that the men of Rohan have surrounded: “Later in the night when the moon came out of the mist, then occasionally [the Riders] could be seen, shadowy shapes that glinted now and again in the white light, as they moved in ceaseless patrol.” This sounds at first reading as though the Moon is rising, but of course a waxing crescent is always setting after nightfall; we can only assume that “the moon came out of the mist” means actually that the mists were themselves clearing away from in front of the Moon. Clouds are given as the reason that the night darkens again later: “It did indeed become very dark again; for the moon passed westward into thick cloud, and Pippin could not see anything a few feet away.

moon 23.4% full 1419 February 29
From the cliffs of the Emyn Muil, Frodo and Sam see the stars appearing “like small white holes in the canopy above the crescent moon.” The Moon is mentioned several more times after they have descended the cliff and as they encounter Gollum, and then by the time they set off Sam asserts that “The Moon's gone, and the night's going.

Faramir says of this date during conversation at Henneth Annûn that he saw the body of Boromir pass him on the Elven-boat “in the grey dark under the young pale moon”.

moon 26.1% full 1419 February 30
When the old man who appears by the campfire disappears after Aragorn confronts him, we are told that “The moon had set and the night was very dark.
moon 29.1% full 1419 March 1
The moon is visible above Gandalf, Aragorn, and the others as they ride south towards Edoras: “Under the cold moon they went on once more, as swift as by the light of day. ... The miles went by. The waxing moon sank into the cloudy West.” Before dawn Frodo meets Gollum and retains him as a guide, saying “Now for it! The Moon's gone, and the night's going. We'd better start.
moon 32.1% full 1419 March 2
A Nazgûl flies across the Moon as Frodo, Sam, and Gollum emerge from the Marshes before dawn, and we are told: “It was not until the moon had sunk, westering far beyond Tol Brandir, that [Gollum] would get up or make a move.” At the end of the day the Riders of Rohan make camp on their way to battle with the forces of Saruman, and “In a great circle, under the starry sky and the waxing moon, they now made their bivouac.
moon 35.2% full 1419 March 3
After driving Orcs from the doors of the fortress in the early night, Éomer and Aragorn halt before the gates and see “The clouds were torn and drifting, and stars peeped out; and above the hills of the Coomb-side the westering moon rode, glimmering yellow in the storm-wrack.” Later, when Gimli announces that he killed two orcs, “The sky now was quickly clearing and the sinking moon was shining brightly. But the light brought little hope to the Riders of the Mark.” Finally, “Aragorn looked at the pale stars, and at the moon, now sloping behind the western hills that enclosed the valley.

And when later recounting the destruction of Isengard by the Ents, Pippin remembers the same westerning moon: “‘It must have been about midnight when the Ents broke the dams and poured all the gathered waters through a gap in the northern wall, down into Isengard. The Huorn-dark had passed, and the thunder had rolled away. The Moon was sinking behind the western mountains.’

moon 38.3% full 1419 March 4
Above Gandalf as he leads King Théoden towards Isengard, “The slow moon mounted, now waxing towards the full, and in its cold silver light the swelling grass-lands rose and fell like a wide grey sea.” The wolves scavenging at the Fords slink away when they see “Gandalf in the moon, and Shadowfax his horse shining like silver.
moon 41.6% full 1419 March 5
Hours before dawn, as they approach Isengard, we are told that “Dark lay the vale before them, for the moon had passed into the West, and its light was hidden by the hills.” Even later “the watchmen cried out, and all awoke. The moon was gone.

The Moon appears again that evening after dark as they are returning southward from Isengard: “Night came down from the mountains. All the mists were gone. A chill wind blew. The moon, now waxing round, filled the eastern sky with a pale cold sheen.” A few more references are made to the Moon, adding no further information, as Pippin steals and looks into the Palantír and then as a Nazgûl passes across the Moon's face.

From the point of view of Frodo and Sam and Gollum, “The moon was now three nights from the full, but it did not climb over the mountains until nearly midnight, and the early night was very dark.

moon 44.9% full 1419 March 6
Before dawn Aragorn as he is overtaken by the Dúnedain sees “The sinking moon was obscured by a great sailing cloud”. In the evening, Frodo etc see “The night became fine under star and round moon”.
moon 48.2% full 1419 March 7
As Pippin rides east with Gandalf on Shadowfax, we are told that on “the third night since he had looked in the stone” he saw “the moon rising above the eastern shadows, now almost at the full.” This raises the difficulty that the third night could refer either to the evening of the 7th or the 8th, depending on how one counted; but fortunately the ambiguity is resolved a few paragraphs later when Pippin wonders where Frodo is and we are told that Frodo was looking on “that same moon as it set beyond Gondor ere the coming of the day.” This means that we correctly place this observation such that the following morning Frodo is seeing the full moon set from Henneth Annûn.
moon 51.8% full 1419 March 8
When Faramir wakes Frodo he says “the full moon is setting”, and when the Hobbits go outside they indeed see that “in the West the full moon was sinking, round and white.
moon 55.7% full 1419 March 9
When in the evening Théoden reaches Dunharrow, he tells Éomer that “Last night the moon was full, and in the morning I shall ride to Edoras to the gathering of the Mark.
moon 59.7% full 1419 March 10
In the morning before dawn, as Gollum leads Frodo and Sam westward towards the crossroads, “the sinking moon escaped from the pursuing cloud”.
moon 11.5% full 1419 March 24
As the armies of the West spend the night encamped in the desolate plain before the Black Gate of Mordor, we are told that “the waxing moon was four nights old, there were smokes and fumes that rose out of the earth and the white crescent was shrouded in the mists of Mordor.
moon 54.0% full 1419 April 8
As Frodo and Sam relax in the evening after being honored on the Field of Cormallen, “the round Moon rode slowly above the mists of Anduin and flickered through the fluttering leaves”.
moon 1.6% full 1421 September 22problematic
As Frodo and Sam ride through the Shire at night with Elrond, Galadriel, and the other High-Elves who are leaving Middle-earth, the text tells us that “the Moon went westward” above them. In fact, it seems that no moon should have been visible.
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