NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Interpolation to latitude
From: Peter Hakel
Date: 2009 Nov 12, 17:52 -0800
From: George Huxtable <george@hux.me.uk>
To: navlist@fer3.com
Sent: Thu, November 12, 2009 4:09:37 PM
Subject: [NavList 10608] Re: Interpolation to latitude
Joe Schultz wrote-
"...2. The daily pages of a paper nautical almanac are very elegant. Enter
the daily pages with approximate time (left side) or position (right side),
then extract position (left) or time (right) data. Then apply some form of
latitude and longitude corrections to get "exact" position or time. And the
daily pages operate in a zone time world, just like we do in our daily
lives."
===================
No. The Nautical Almanac works throughout in GMT, not in Zone Time.
--~--~---------~--~----~------------~-------~--~----~
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList+@fer3.com
-~----------~----~----~----~------~----~------~--~---
From: Peter Hakel
Date: 2009 Nov 12, 17:52 -0800
The Rising and Setting Phenomena section of the Nautical Almanac states:
"On the right-hand daily pages are given the times of sunrise and sunset, [...] twilights [...]"
"These times, [...], are strictly the UT of the phenomena on the Greenwich meridian; [...]"
"They are approximately the Local Mean Times (LMT) of the corresponding phenomena on other meridians; they can be formally interpolated if desired."
"The tabulated times may be regarded, without serious error, as the LMT of the phenomena on any of the three days on the page and in any longitude. Precise times may normally be obtained by interpolating the tabular values for latitude and to the correct day and longitude; [...]"
Peter Hakel
"On the right-hand daily pages are given the times of sunrise and sunset, [...] twilights [...]"
"These times, [...], are strictly the UT of the phenomena on the Greenwich meridian; [...]"
"They are approximately the Local Mean Times (LMT) of the corresponding phenomena on other meridians; they can be formally interpolated if desired."
"The tabulated times may be regarded, without serious error, as the LMT of the phenomena on any of the three days on the page and in any longitude. Precise times may normally be obtained by interpolating the tabular values for latitude and to the correct day and longitude; [...]"
Peter Hakel
From: George Huxtable <george@hux.me.uk>
To: navlist@fer3.com
Sent: Thu, November 12, 2009 4:09:37 PM
Subject: [NavList 10608] Re: Interpolation to latitude
Joe Schultz wrote-
"...2. The daily pages of a paper nautical almanac are very elegant. Enter
the daily pages with approximate time (left side) or position (right side),
then extract position (left) or time (right) data. Then apply some form of
latitude and longitude corrections to get "exact" position or time. And the
daily pages operate in a zone time world, just like we do in our daily
lives."
===================
No. The Nautical Almanac works throughout in GMT, not in Zone Time.
--~--~---------~--~----~------------~-------~--~----~
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList+@fer3.com
-~----------~----~----~----~------~----~------~--~---
