NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Can you work a Polaris problem just like any other star?
From: Gary LaPook
Date: 2014 Jan 4, 23:30 -0800
From: Gary LaPook
Date: 2014 Jan 4, 23:30 -0800
Yes you can, just treat it like any other body if you are using a computer, calculator, slide rule or log table reduction method. If using tables only HO 229 covers declinations up to 90 degrees so the other common tables such as HO 249 can't be used to reduce a Polaris sight. The "latitude by Polaris" method was popular because it was shorter and quicker than conventional tables. There is also the "Q" diagram in HO 249 and in the Air Almanac that provides the correction for the short Polaris method, see:
http://fer3.com/arc/m2.aspx/Polaris-correction-tables-LaPook-may-2013-g23868
gl
From: Greg Licfi <cfi@licfi.com>
To: garylapook@pacbell.net
Sent: Saturday, January 4, 2014 6:52 PM
Subject: [NavList] Can you work a Polaris problem just like any other star?
http://fer3.com/arc/m2.aspx/Polaris-correction-tables-LaPook-may-2013-g23868
gl
From: Greg Licfi <cfi@licfi.com>
To: garylapook@pacbell.net
Sent: Saturday, January 4, 2014 6:52 PM
Subject: [NavList] Can you work a Polaris problem just like any other star?
Hi All,
Please help me out if you can; am I wrong in thinking that
can you work a Polaris problem just like any other star?
I know that the USNO Nautical Almanac has a set of tables;
I believe they are called A0, A1, & A2 and when you add up all
three corrections and subtract 1 degree you get your latitude.
I began to think about this because I just bought a program
called 'AstroNav' it is a almanac program that goes from 2000BC
up to 8000AD so It has more of a range then I will ever need :)
It also has the option to only print out only the pages I need rather
then lug an entire almanac around. It does not however, have the
USNO type Polaris tables however, and lists Polaris just like any other
star. So far I can not find any discrepancy between ICE, a android
app called: 'Celestial' by Navimatics Corp, and the USNO nav data
page. So I'm guessing the mechanics are all the same. I once modified
a nocturne to show the error but I don't think it worked exactly correct.
I belive that early explorers (on land) used to sit up late into the night
with a sextant and mercury horizon waiting for Cassiopeia and Ursa Major
to be parallel to the horizon (happens twice in 24 hours) supposedly the
error is zero at that time, and they could read the latitude directly, after
correcting for IE, etc.
Thanks,
~Greg
: http://fer3.com/arc/m2.aspx?i=126166
