EDIT: The current build of the spreadsheet may be downloaded from here. I'll be updating it infrequently, so be sure to check back from time to time.
CHANGELOG
Spoiler:
1.2 — Automated realignment of the days of the week, lunar cycle, and Shade of the Revenant when adding or removing an era's "year zero". Summoning Days now displayed separately from holidays.
1.1 — Added options to add or remove an era's "year zero" and realign the days of the week, lunar cycle, and Shade of the Revenant accordingly. Updated usage instructions. Removed Nocturnal's Summoning Day as a separate holiday.
1.0 — Initial release.
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I'm working on an Excel document that will hopefully recreate Tamriel's calendar to the greatest possible degree of accuracy. So far, it can track the days of the week, the phases of the moons and the occurrence of the Shade of the Revenant for any given date, but I'm still missing information on the movements of the Serpent and the occurrence of lunar alignments (the rare phenomenon that results in the birth of a Mane).
The Dawn Era is ignored, for obvious reasons. For the sake of convenience, I'm assuming the other eras all begin on Morning Star 1 and end on Evening Star 31 without fail. I'm also assuming that only the Merethic Era and the Second Era lack a "year zero", based on information from their respective articles here at UESP.
Skyrim is the point of reference for the days of the week; interestingly, this causes 3E 399 to match the physical calendar shipped with Arena perfectly.
The point of reference for the Shade of the Revenant is Oblivion, again for obvious reasons.
Spoiler:
It is further assumed not to begin occurring until shortly after the Warp in the West, as it is dependent upon Mannimarco's ascension to godhood.
For slightly less obvious reasons, Morrowind is the point of reference for the phases of the moons, as I believe it is the only game in which all phase combinations are possible. The fairly lengthy explanation may be found in the spoiler below.
Spoiler:
In Arena and Daggerfall, the moons are offset from each other slightly, but their cycles are otherwise identical, from what I understand. Meanwhile, Oblivion and Skyrim have them out-and-out phase-locked. In Morrowind, Masser is the same as always, but Secunda is given a longer and slightly erratic cycle. The default INI settings suggest the duration of Secunda's cycle to be exactly 1.2 times that of Masser; since it can't really change phases in the middle of the day (as far as I know), this results in an odd pattern that repeats after five cycles. Some online digging confirms that others have reached similar conclusions before me based solely on in-game observation.
To be clearer:
Each moon has eight phases (new, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, second quarter, waning crescent).
Masser's cycle lasts 24 days, with each phase lasting three days.
Secunda's cycle lasts 28-29 days, with the phases following a pattern of three, four, three, four and four days. Since that pattern only accounts for five of the eight phases at a time, it takes five full cycles (or 144 days) to loop all the way back around to the beginning. This is exactly equal to six Masser cycles.
Since the Construction Set gives "new" as the default phase for both moons, I'm considering the beginning of that phase to mark the beginning of their combined cycle. All possible phase combinations do occur this way, though some are more frequent than others. Assuming that the first day of the game (Last Seed 16, 3E 427) then uses the default setting and therefore marks the beginning of a cycle, a viable reference point is created for every other possible date.
Corrections? Additions? General thoughts?
Last edited by Glitchipedia on Sun May 23, 2021 6:23 am, edited 3 times in total.
Well, the spreadsheet is about as finished as it's going to get at the moment, but I don't currently appear able to upload or link to it here. I may require the assistance of a moderator, or else directions to an alternative venue.
