NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Lunar Distances with Alex's SNO-T
From: Fred Hebard
Date: 2006 Oct 31, 09:17 -0500
From: Fred Hebard
Date: 2006 Oct 31, 09:17 -0500
That's correct! I started looking into this, but gave up. Hopefully, the physicists will jump in here. On Oct 31, 2006, at 8:59 AM, Alexandre E Eremenko wrote: > > > Fred, > I see, this sounds reasonable. > But then I need a barometer, or to correct > the pressure from the Weather channel for > my altitude, because, > if I understand correctly, the pressure broadcast > for the weather prediction is reduced to the sea level. > > Alex > > On Tue, 31 Oct 2006, Fred Hebard wrote: > >> >> >> Alex, >> >> Use the actual pressure. That is the determinant for the refraction >> correction. The elevation above sea level has an insignificant >> effect on parallax, when you consider that the radius of the earth is >> about 3400 nautical miles, but significantly reduces refraction via >> the effect on barometric pressure. >> >> Fred >> >> On Oct 31, 2006, at 8:27 AM, Alexandre E Eremenko wrote: >> >>> Related question: the barometric pressure in the refraction formula. >>> Should I use the actual pressure at my observation site, >>> or should I "reduce it to the sea level"? >>> The actual pressure at my site reflects not only the deviation >>> from the standard atmosphere but also my altitude over the sea >>> level. >>> >>> Alex >>> >> >> >>> > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to NavList@fer3.com To , send email to NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
