Has some excellent questions and information about Equiyelms and Perixenths. :)
>> Spring and Autumn would likely be the same length of time.
>
>No, see below.
>
>I assumed by Summer you meant from summer "solstice" to autumnal
>equinox, and that spring would be from vernal equinox to summer
>"solstice". After all, you'd just asserted what the quarter days were,
>and that is the usual definition. Certainly none other was in evidence.
>Given these, the seasons are of the following lengths:
>
>Spring: 67
>Summer: 68
>Autumn: 79
>Winter: 80
>
Yes, I had forgotten that was the accepted definition -- it has always
made little sense to me, since I judge seasons primarily by local
temperature and precipitation, which have alwayse seemed closer to
centering on the solstices than beginning on them. My error.
My proposal is that the Summer "Solstice" be Midsummer day, be the middle of the summer, being Yelm's HHD. Thus, the Spring Equinox is more properly the middle of Spring, not the beginning. Thus, your comment about Solstices and Equinoxes from before, that the terms are incorrect in Glorantha, is correct. Again, my error for being imprecise in my intent.
>So with a half-day tweak, that is, putting the equinoxes at midnight and
>mid-{summer|winter} at noon, or vice versa, or something to that effect,
>then S/S and A/W each come out to be respectively equal. This may even
>make sense, though I'll have to go think about it some more.
>
I would have to analyze weather patterns and season beginnings/endings.
Feel free to do it if you'd like. Personally, I can handle winter being
longer than summer, but not that and also Autumn being longer than Spring
- -- the forces of Life would be hard-pressed in that case.
>> 10.6 / 9 = 1 1/6,
>> so the difference in lengths between equinoxes should be the same
>
>Now I see where you're coming from. The next question is, even
>given this ratio, how do you arrive at the absolute numbers?
>The only pertinent fact I can think of is that Polaris is always
>within the Upper Circle, which means the maximum swing would be
>about 15 degrees, if the diagram on GRoY p80 is "to scale".
>
Actually, the distance to the Upper Circle is, per Greg's working notes,
1/10 of the distance to the horizon, in other words 9 degrees. I took
that as defining the northern tilt, so that summer was always "perfect"
- -- Polaris did not leave the Upper Sky, from a Buserian point of view.
Winter was intentionally taken outside of this circle. As to _why_ it was 10.6 degrees, I'll have to try to find my notes -- I had a _really_ good reason, honest! Greg liked it a lot, too! Oh, yeah, that's right -- I wanted the Spring and Autumnal Equinoxes to be on specific dates -- Day 1 (1st day of Sea Season) and Day 135 (Earth Cults HHD. I also wanted to keep Nick's belief that Yelm's HHD was the Summer Solstice. Finally, I wanted day length to change in direct proportion to the tilt. All this combined to give a tilt of exactly 10.6 degrees, which seemed to fit the esthetics well. Much more, and the degree of tilt would have been even more alarming than it is. Much less, and the northern tilt had to be reduced as well.
Setting the tilts in advance at 9 degrees and 12 degrees gave me some very short or long seasons, I can't quite recall which.
>I'm enough of a mathematician to tell you that 159/135 = 1.1777777...,
>not 1 1/6 ( = 1.1666666...), and enough of an astronomer to have a hard
>time seeing how much of a (feasible) correspondance between "real"
>celestial mechanics and Gloranthan ones there ought to be (not least as
>establishing any observable facts is extremely slippery).
Unless I'm wrong, the actual lengths are not 159 and 135, they have 1/2's in there as well, because the Equinoxes fall at noon but the Solstices each fall at midnight. As I recall, it comes out to exactly 1 1/6 when that is done. I was simplifying in the interest of general interest.
As for earthly astronomy applying, I am of the firm belief that as many physical processes in Glorantha as possible should correspond to apparent earthly phenomena.
Let me at
>least try to determine what assumptions your calculation is based on.
>I'm surmising:
>
> o That at the equinoxes, the sunpath is directly overhead
> (as if one was at earth's equator);
>
Correct.
> o Each successive day varies in length from the preceeding
> by an equal amount (not true of earth at all).
> (2m7s (and a bit), trivia fans.)
>
Also correct, on both points. However, how _close_ is the correspondence
at say, the latitudes of the United States? Close enough that most people
would think the differences were the same?
>[ES quote]
>> Clearly, the Dome rocks north of center, then back, then south, then
back.
>
>In at least one place in _each_ of ES and GRoY, it gives at least as
>unequivocably that the midsummer sun passes directly overhead, so I
>don't know why you think this is so "clear".
>
Where in Elder Secrets does it contradict this statement? I know GRoY
does, but that was based on an earlier belief. As a work in progress, I
have no problem abandoning that "fact" in GRoY. ES I am more wary of
contradicting, since I dislike Greg _contradicting_ older sources (unless
there is a good cultural explanation for why).
>> No, the Dome rocks both north and south, though Nick's Starmaps
program
>> has it go to center at midsummer. This was an attempt, if I remember
>> correctly, to justify having both summer and winter stars, impossible
>> given the Elder Secrets model.
>
>I'm not quite sure what you mean by the ES model, given all the
>acknowleged inconsistencies therein. But I see what you mean about
>the summer stars; are there any significant such, though? I'll
>be sure to pore over the ES and GRoY lists later. (I know they're
>alluded to collectively, I mean particular instances.)
>
There are three summer constellations on Greg's "master" star map, and
two winter constellations. There are probably a few individual stars as
well, though we have not discussed this. Of the Winter and Summer
constellations, two are of great importance -- if my model is correct,
Ice Palace is _always_ due north when it is visible, which seems
appropriate, and the constellation called by the Doraddi Pamalt's Spear
is always directly south, also appropriate. Note that Stormgate/the Pit
does not rotate, but it does rock north and south, indicating it is
probably on this other Dome.
>> [Steve needs] a second major dome, one which tilts but does not
>> rotate. With this Dome in place, the dome again tilts both north and
>> south of the center.
>
>I'm all confused again... When you say "a second major dome", are you
>speaking of Buserian-style "horizon/underworld" lines on the "frame" (or
>on the sky itself), or are you talking about some sort of "Crystal Dome"
>required to account for the celestial mechanics of it all?
The latter, a "Crystal Dome" in high Greek Astronomy fashion -- the primary dome has most of the stars on it, and both tilts and rotates. This secondary dome tilts but does not rotate.
(As in, a
>crystal sphere with most of the bottom sawed off.) I can see the need
>for the first, though not the second -- surely we're just talking about
>a single Dome, with two components of motion? Multiple crystal
>domes might make a suitably wacky Western theory, though... (and would
>explain a south-only tilt too).
>
Multiple crystal domes were the dominant theory in Astronomy for a few
thousand years, and are specifically how the Gloranthan sky works, per
Greg in GRoY (Ivory edition). And it is required to have both summer and
winter stars, since the current model (rotating and tilting) allows for
only one of them. If you believe the Crystal Dome theory, which I do.
>Indeed so. This also raises the question of whether the sun has the
>same apparent speed across the sky all day, or if speeds up near the
>zenith in winter, and slows down in summer. (That almost made sense for
>a moment, though it made my head hurt thinking about it.)
>
The apparent speed at the zenith and horizons, if present, is negligible.
However, the Sun should move much slower in summer than winter (and
Lightfore do the reverse), since it is covering the same distance in a
much longer time period.
>> But, for esthetic reasons, days should be longer in summer and
>> shorter in winter, and having them correspond to the amount of
>> tilt gives what I feel to be acceptable durations.
>
>Perhaps I have too much of a high-latitude aesthetic, but I'd have
>found greater variability to be more intuitive. Though, while Dara
>Happa's a pretty "high latitude" place, I don't know if the length
>of the days and nights are a pan-Gloranthan phenomenon. I suppose
>they ought to be, if the sun rising and setting dead east and west
>everywhere is (not Greg made his mind up about that).
>
As far as I gather from GRoY and talks with Greg, the Sun alwasy rises
due east and sets due west. And, since Glorantha is a lozenge, not a
globe, day and night lengths should not vary at all in different places
in Glorantha.
Stephen Martin
ilium_at_juno.com
- -----------------------------------------------The Book of Drastic Resolutions
End of The Glorantha Digest V5 #19
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