NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Star-star distances for arc error
From: Peter Hakel
Date: 2009 Jun 19, 22:22 -0700
From: "frankreed@HistoricalAtlas.com" <frankreed@HistoricalAtlas.com>
To: NavList@fer3.com
Sent: Friday, June 19, 2009 8:03:04 PM
Subject: [NavList 8738] Re: Star-star distances for arc error
Peter, you wrote:
"Neat trick!"
Thanks. Glad you tried it out.
You wrote:
"For refraction I took the formula from the Nautical Almanac at the standard conditions "
Do you mean the formula from the back of the almanac that gives the refraction as R=0.0167/tan(H+7.31/(H+4.4))? That probably explains the slight differences between my numbers and what you found.
-FER
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From: Peter Hakel
Date: 2009 Jun 19, 22:22 -0700
Yes, that's the one. My edition says:
R = 0.0167 / tan( H + 7.32/(H+4.32) )
I also include the correction factor "f" for non-standard conditions: f = 0.28 * P / (T+273), which does not EXACTLY equal to 1 for T=10 and P=1010, but it's pretty darn close (0.9993).
Peter Hakel
R = 0.0167 / tan( H + 7.32/(H+4.32) )
I also include the correction factor "f" for non-standard conditions: f = 0.28 * P / (T+273), which does not EXACTLY equal to 1 for T=10 and P=1010, but it's pretty darn close (0.9993).
Peter Hakel
From: "frankreed@HistoricalAtlas.com" <frankreed@HistoricalAtlas.com>
To: NavList@fer3.com
Sent: Friday, June 19, 2009 8:03:04 PM
Subject: [NavList 8738] Re: Star-star distances for arc error
Peter, you wrote:
"Neat trick!"
Thanks. Glad you tried it out.
You wrote:
"For refraction I took the formula from the Nautical Almanac at the standard conditions "
Do you mean the formula from the back of the almanac that gives the refraction as R=0.0167/tan(H+7.31/(H+4.4))? That probably explains the slight differences between my numbers and what you found.
-FER
--~--~---------~--~----~------------~-------~--~----~
Navigation List archive: www.fer3.com/arc
To post, email NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---
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