Crotali

Jeff Wilson · 20 Jun 2010, 08:14 · from 2010-June.txt.gz

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From: jwilson at io.com (Jeff Wilson)
Date: Sun, 20 Jun 2010 03:14:28 -0500
Subject: (urth) Crotali
In-Reply-To: <AANLkTik8_lbjyL3oXl6OQIvQzgNvtdjoxmPpFJuPdzRM at mail.gmail.com>
References: <4C06DFE0.3040805 at sky.com>
	<4C06E4C7.7020706 at sky.com>	<476916.92692.qm at web50707.mail.re2.yahoo.com>	<4C0AF273.7070303 at sky.com>	<009b01cb0535$75580760$9ace4a0c@rclackey>	<4C0C3D9C.4000106 at sky.com>	<006901cb0606$65730bc0$90cd4a0c@rclackey>	<4C12B912.4090703 at sky.com>	<Pine.LNX.4.64.1006120919370.10088 at orpheus.qimr.edu.au>	<4C1D5C8A.2020403 at sky.com>	<AANLkTimfnGsZ1lGKMLZiYNhQvwQvX4WnM2YtX1Vxp3VA at mail.gmail.com>	<4C1D884A.2050402 at io.com>
	<AANLkTik8_lbjyL3oXl6OQIvQzgNvtdjoxmPpFJuPdzRM at mail.gmail.com>
Message-ID: <4C1DCDE4.1010508 at io.com>

On 6/20/2010 12:20 AM, Mr Thalassocrat wrote:
>
>
> On Sun, Jun 20, 2010 at 12:47 PM, Jeff Wilson <jwilson at io.com
> <mailto:jwilson at io.com>> wrote:
>
>
>     Most constallations' component stars have no physical association
>     among them and only appear to lie closely together as seen from
>     Earth. This lack of unity means proper motion will make them
>     unrecognizable and/or disperse them entirely.
>
>     Precession of the equinoxes however takes place on a shorter scale,
>     currently a bit under about 26,000 years per full ciruit of pole
>     stars. This implies that Apu Punchau is about 13,000 years before
>     Severian, or 39,000, or 65,000 or 91,000...
>
> You're right, of course.


That's not to say that proper motion has no part to play in the Book. 
it puts a fuzzy upper limit on how many 26,000 year cycles can pass. 
Starting about 03:30, this episode of Cosmos shows a few changing over 
+/- a million years.

http://www.youtube.com/watch?v=TYobCdq9BEA&feature=fvsr

They are unrecognizeable IMO after a million years, so that's about 40 
precession cycles. Also, the displacement seems to be only 1/4 of the 
retrograde precession, spring planting under winter stars, so the split 
could be as little as 6500 years before adding multiples.

Hmp - reading Urth's appendix in this light seems to confirm not just 
the Ship's intervention in the eclipse, but the truly continental size 
of the mirror-sails: not just the 1/2 degree width of the moon is 
covered, as if by a Yesodi peephole, but several constellations worth of 
arc of mirror would be required to allow Severian to see his familiar 
constellations out of their season.

-- 
Jeff Wilson - jwilson at io.com
IEEE Student Chapter Blog at
< http://ieeetamut.org >

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