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Re: Getting ready for a spring demo...
From: Mike Mayer
Date: 2013 Dec 30, 09:36 -0600

Here’s a place that has a variety of levels:

http://www.geier-bluhm.com/

==================================================================

Mike Mayer

mwmayer@tds.net

From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Greg Licfi
Sent: Monday, December 30, 2013 8:53 AM
To: mwmayer@tds.net
Subject: [NavList] Re: Getting ready for a spring demo...

Hey Guys,
Sorry for all the hub-bub;
I was working in degrees and not radians
I just never hit the TAN key *ARG*
I thought I did but didn't if i had:
1/60th of a degree (0.016666)
TAN(0.01666)=0.000290888
0.000290888 X 72" = 0.02"
Ah, too clever by half.
looks like I have to go out now and buy a
machinists level there is just no way to
re calibrate a cheap level into an expensive one.
Thanks again,
~Greg

On 12/30/2013 01:27 AM, Gary LaPook wrote:

3600 is the approximation for rifle shooting, one inch at one hundred yards (3600 inches) is approximately one minute of angle.

gl

From: Frank Reed <FrankReed{at}HistoricalAtlas.com>
To: garylapook---.net
Sent: Sunday, December 29, 2013 6:47 PM
Subject: [NavList] Re: Getting ready for a spring demo...

"use 3600 instead of 3438, it's easier to do The math in your head."
Well, sure. :)
You memorize 3438, then if you're working in your head and don't have a calculator nearby, replace it by whatever is convenient. In one circumstance 3600 might be convenient, in another 3400 might be convenient. Heck, even 3000 is fine for a quick estimate. But memorize a value that's as close as possible within the constraints of the usual problem of memorizing anything. Back in the 18th century, Nevil Maskelyne usually quoted 3437.75.
All you need is ONE "magic number": 3438.
-FER
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