Re: Eclipses

From: Alex Ferguson <abf_at_cs.ucc.ie>
Date: Mon, 2 Jul 2001 04:40:34 +0100 (BST)


Me'n'Jules:
> > > I myself would have thought that *something* at least must occur when the
> > > *apparent* directions & heights of the Moon and Sun coincide
> >
> > Assuming they're of equal sizes, at least, yes.
>
> Or : similar enough "apparent" sizes, and yes the objection had occurred to
me.

Indeed, I mean apparent sizes. Or if the RM were (apparently) larger, even.

> > First of all, note that while the position of the red moon is always
> > the same, the height of the sun varies seasonally; therefore, no
> > place suffers total eclipses _daily_, which was my original observation.
>
> Ah, I see ; you were just being cheeky then and/or obfuscating ?
> No problem...

I thought that since you asked about daily eclipses, and I answered specifically in those terms, I was being astonishingly responsive...

> > No; though the truth may be odder still. ;-) My current understanding
> > (thinking, or assumption, as the case may be) is that: a) the red moon
> > is always in the apparent direction of Glamour;
>
> The Crater surely ? (quibble, quibble, toil and tribble as at least one
> cross-posting openherowarser might put it)

Indeed, Crater. My bad.

> > b) it doesn't have a
> > "physical height", at least inside of the Glowline; rather, it appears
> > in effect to be "in" the Sky;
>
> But this might not prevent it from having an "apparent" height ?

It has an apparent position in the sky, obviously. This doesn't (necessarily) mean it has a "height", in any mathematically sensible sense.

> > and c), the Glowline itself effects
> > what _part of_ the sky the moon is seen in (and possibly even whether
> > it's part of the Sky, or part of the Middle Air).
>
> hmmm ... sounds pretty weird. If true, does this mean that the RM over Sartar
> (sorry couldn't resist the pith) "apparently" acts like a yo-yo during the
> Dragonrise ?

Sounds about right. Or a heckuva flickery "horizontal hold", at least...

> I've been wondering about the Silver Shadow in this respect. While it seems
that
> the line around the SS must once have been the edge of the Glowline, I have
also
> been wondering if it mightn't have some other celestiological meaning, ie that
> it's northernmost point might be the place where an eclipse occurs at midday
> during one of the solstices ?

Oof. Interesting question. Factors preventing a cogent answer at this time include not being quite sure about what the moon's position is, not knowing the northern and southern extent of the sunpath at the solstices, and it being 4:30am...

> Related question : have the imaginary lines of the Sunpath during the
solstices
> (those places where the Sun "appears" as passing directly overhead during the
> course of those two days) been worked out ?

I don't follow the question. The sun doesn't appear overhead at the solstices at all. (And the Sunpath is a (great circle) arc across the sky, not a line in the lozenge, if that's what you're saying here.)

G'night,
Alex.


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