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Re: Maskelyne and his "able computers"
From: Frank Reed CT
Date: 2004 Sep 24, 22:22 EDT
From: Frank Reed CT
Date: 2004 Sep 24, 22:22 EDT
George H wrote:
"I'm less convinced by Frank's follow-up, however, in which he said-
>The lunar distance, LD, is calculated from the
>difference in ecliptic longitude and latitude using the simple rule
> cos(LD) = cos(diff_longitude)*cos(diff_latitude)
>With the stars and planets, the ecliptic latitudes are low enough that
>certain approximations can be applied which also reduce the task of
>computation.
>Rotating to RA and Dec would lengthen the calculations quite a bit.
Hi again, George! By omitting the previous sentence from my earlier post, you have missed the point. The equation posted was for Moon-SUN lunars. Get it?
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois
"I'm less convinced by Frank's follow-up, however, in which he said-
>The lunar distance, LD, is calculated from the
>difference in ecliptic longitude and latitude using the simple rule
> cos(LD) = cos(diff_longitude)*cos(diff_latitude)
>With the stars and planets, the ecliptic latitudes are low enough that
>certain approximations can be applied which also reduce the task of
>computation.
>Rotating to RA and Dec would lengthen the calculations quite a bit.
Hi again, George! By omitting the previous sentence from my earlier post, you have missed the point. The equation posted was for Moon-SUN lunars. Get it?
Frank R
[ ] Mystic, Connecticut
[X] Chicago, Illinois