NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Brad Morris
Date: 2013 Mar 26, 22:02 -0400
Hi Sean
Here's how to do arcsin, arccos and arctan.
Let's assume you want the arcsin(.43). Set your cursor on the D scale to 430. Read on the S (sin) scale the value 26 degrees.
Let's assume you want the arctan(.707). Set your cursor on the D scale to 707 (okay 710). Read on the T scale 35 degrees
Lets assume you want the arccos(.350). Set your cursor on 350 on the D scale. Flip the scale over and read on the S scale 21. Cos(angle)=Sin(angle-90), so your answer is (90-21=) 69 degrees.
These answers are not exact but show the method. You can do better with more careful manipulation of the cursor.
Regards
Brad
I purchased a Pickett model N902-ES "slipstick" from eBay. I remember having a slide rule around the house when I was a kid, but this has been my first 'real' experience with one. (Not counting the flat Bygrave.)
I am enjoying learning how to use it immensely. Seriously, this thing is way handy. I just tried running through the formulae for determining a DR from the N.A. (L1=Lf+t(v/60)sin(T)/cos(Bf), etc.) My results were remarkably accurate!
I'm now one step closer to surviving the E.M.P. apocalypse. :P
P.S.
Is there any way to figure arcsin/arccos on the average slide rule. Or is that why Capt. Bygrave invented his rule?-Sean C.
----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
----------------------------------------------------------------
