NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Almanac for Computers
From: Michael Wescott
Date: 1996 Aug 29, 17:00 EDT
From: Michael Wescott
Date: 1996 Aug 29, 17:00 EDT
John H Henderson wrote: > This brings another question to mind....do the almanacs/sight > reduction tables/computers take the oblateness of the earth into > account? I figured out HO211, and it does not. And since the > almanacs don't take your position into account, I do not believe > that they can either. There is no need. Longitude and latitude are astronomical, derived from actual or projected observations with respect to the local horizon. In other words, at a given spot latitude will be based on the angle that a perpendicular to the tangent plane makes with the equatorial plane. This is not the same as the angle made by the equatorial plane and the line through the center of the earth from the spot. Only when distances are involved does the actual shape of the earth become an issue, and then, as a practical matter, only when the distances are fairly large (on the order of a hundred miles or so). <PRE> -- -Mike Wescott mike.wescott@XXX.XXX ------------------------------------------------------------------------ This mail list is managed by the majordomo program. To from this list, send the following message to majordomo@XXX.XXX: navigation For help, send the following message to majordomo@XXX.XXX: help Do NOT send administrative requests to navigation@XXX.XXX -ben ------------------------------------------------------------------------ </PRE>
