The Apu-Punchau Eclipse

Dan'l Danehy-Oakes · 11 Jun 2008, 15:27 · from 2008-June.txt.gz

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From: danldo at gmail.com (Dan'l Danehy-Oakes)
Date: Wed, 11 Jun 2008 08:27:43 -0700
Subject: (urth) The Apu-Punchau Eclipse
In-Reply-To: <484F2558.1050806 at io.com>
References: <cf4.2e47ed06.357fd706 at aol.com> <484E96F1.1010805 at io.com>
	<1f7617370806100930j27eed455j2f0108135077d988 at mail.gmail.com>
	<484F2558.1050806 at io.com>
Message-ID: <1f7617370806110827m1b35c02dm5088612b6f5d0d03 at mail.gmail.com>

On Tue, Jun 10, 2008 at 6:07 PM, Jeff Wilson <jwilson at io.com> wrote:
> Dan'l Danehy-Oakes wrote:
>>
>> Tzadkiel's Ship -- *counting its sails*, is significantly bigger than a
>> mile
>> in diameter, at least for purposes of shadow-casting. Solar sails have
>> to be (a) very very large and (b) quite opaque in order to be effective.
>
> LEO velocity is about 5 miles per second, so each second of eclipse is 5
> miles worth of ship, plus the penumbra penalty (altitude times twice the
> tangent of the sun's arc width (0.5 degrees)). There would also need to be
> some means of maneuvering the entire ship within a moment or a massive
> number of crew available to trim the sails in a like period of time.

The numbers I've seen for an effective solar sail are in the range of
tens of thousands of miles.


-- 
Dan'l Danehy-Oakes, writer, trainer, bon vivant
-----
http://www.livejournal.com/users/sturgeonslawyer
http://www.danehyoakes.com

I once absend-mindedly ordered Three Mile Island dressing in a
restaurant and, with great presence of mind, they brought Thousand
Island Dressing and a bottle of chili sauce. -- T. Pratchett

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