NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: spherical triangle
From: Robert Eno
Date: 2007 Jun 08, 09:49 -0400
>
> I new here, and have an odd question.
>
> I was reading this article,
> http://articles.adsabs.harvard.edu/cgi-bin/nph-
> iarticle_query?1978JRASC..72...69F&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf and the author described the spherical triangle as this.
>
> a Triangle consisting of the
> North pole, Zenith, and Postition of the Sun.
>
> The angle at the Zenith is the Azimuth. The angle at the North
> Pole is the Hour angle.
> The line connecting the Zenith and the Pole is the subtend angle
> Co-latitude.
> The line connecting the Zenith and the Sun is the subtend angle
> Co-altitude.
> The line connecting the Sun and the Pole is the subtend angle Co-
> declination.
> What does the angle at the Sun represent?
>
> thanks,
> Wayne
>
>
>
> ---------------------------------
> Need a vacation? Get great deals to amazing places on Yahoo!
> Travel.
>
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From: Robert Eno
Date: 2007 Jun 08, 09:49 -0400
Wayne,
If you look at Dutton's Navigation and Piloting (14th ed), they refer to it as the "parallactic angle". Beyond that, I am not aware of it being used in practical art of navigation.
I am certain, however, that one of our resident mathematical geniuses will be able to provide a more detailed explanation.
cheers,
Robert
----- Original Message -----
From: Rebecca Lowry <xachaniwa@yahoo.com> Date: Friday, June 8, 2007 7:24 am Subject: [NavList 2947] spherical triangle > Hi,>
> I new here, and have an odd question.
>
> I was reading this article,
> http://articles.adsabs.harvard.edu/cgi-bin/nph-
> iarticle_query?1978JRASC..72...69F&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf and the author described the spherical triangle as this.
>
> a Triangle consisting of the
> North pole, Zenith, and Postition of the Sun.
>
> The angle at the Zenith is the Azimuth. The angle at the North
> Pole is the Hour angle.
> The line connecting the Zenith and the Pole is the subtend angle
> Co-latitude.
> The line connecting the Zenith and the Sun is the subtend angle
> Co-altitude.
> The line connecting the Sun and the Pole is the subtend angle Co-
> declination.
> What does the angle at the Sun represent?
>
> thanks,
> Wayne
>
>
>
> ---------------------------------
> Need a vacation? Get great deals to amazing places on Yahoo!
> Travel.
>
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---