Talk:Navigation by the Stars

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Assumung you labeled 'Right Ascension' as Longitude, I started looking up the RA and Declinations of the stars you listed in the table in Norton's Star Atlas - and they don't correspond to stars in our 'real' sky. Did you just make up those numbers on the fly or did they actually come from a real table?

The other thing I should do is plot those co-ordinates on an actual star chart to see if they do follow the line of the ecliptic .. or within five degrees of it - and some of them are way off.

Also looking at the spreads of RA's/decs for the same constellation listed, they're just too big. There should be a steady progression of RA numbers as one goes around the zodiac from sign to sign.

--Keith 21:41, 13 Mar 2008 (NZDT)

Sorry - missed this entry first time around. The stars of Alusia don't correspond to those of Earth. If nothing else, there is a Constellation called the Void, which presumably has very few medium or large stars in it. These are arbitary, vaguely spread out locations within +/- 23.5 degrees north/south, corresponding to a similar number of stars in this band on Earth.

Rather than 'Right Ascension', what I have labelled as Longitude is the number of degrees to the right (East, as North is at the top) that the Star can be found relative to the left hand edge of the constellation that it is found in, which is why it varies from 0 to ~25.7 degrees (360/14). It's local Longitude within the star sign, and is exactly the method used by William Bourne in his remarkably similar (though inferior!) book on Earth navigation. I probably should explain it somewhere.

To save you plotting these on a star chart, the graphic supplied on the page is an exact (within 1/2 degree) plot of the positions of the stars (thank you Excel) - the size of the star symbol corresponds to its brightness, and the stars decribed as red or blue are appropriately tinged. It's supposed to be effectively a star plot of 23N to 23S, by 360 degrees (the major stars that lie between the tropics of cancer and capricorn). I'm not sure why they need to be within 5 degrees of the ecliptic - I'm probably missing some relevant astronomy knowledge here. The rising / setting points and latitudes indicate that they are vaguely equatorial, but no more than that, again matching the range and distribution of the major stars listed by William Bourne.

The names of the stars are supposed to be evocative of their constellation, and their approximate place within it - one or two of the stars got moved so that I could use a name that I liked. Others of the names aren't great.

--Andreww 00:58, 2 May 2008 (NZST)