Re: See the New Tether! and re: Orientation Format

Jim Varney (jvarney@mail2.quiknet.com)
Fri, 16 Aug 1996 22:32:41 -0700

Walter wrote:

>> >sp could be count of sparkles 

I'm a little unclear on the definition of a "sparkle."
How does it differ, if it all, from FFF or ssm?

>> Vertex angle is usually not measured from the apparent vertical. 
> 
>I don't know this.  Do you have a reference? 

Oops, my error.  I was thinking of p.a. and celestial north.

Now that you've convinced me that there won't be any confusion over
the definition of 'vertex angle,' I think the v.a. system is fine.
Just to be sure I have this correct: 20 deg LML = 20 deg v.a. and
20 deg LMF = 160 deg v.a.  ...right?

>>In the engineering world the term for deviation from vertical is "slope." 
> 
>The engineers I know about have been taught that slope is the "m" 
>coefficient in y = mx + b.  Which is not measured in degrees. 

m is the algebraic slope of a line, yes.  The slope I was referring to
is the inverse of 'grade,' i.e., a railroad grade of 10 percent can
also be thought of as having a slope of 5.7 degrees.  Common practice
is also to measure slopes as run:rise, as in 2:1 slope... er, time to
get on-topic again :)

>Is there some (desirable) way the observer could be given a choice?  I'm 
>trying to make it easy for the observer to get it right. 

Maybe quote both systems until we get used to v.a., as in "170 v.a.(10 LMF)"?


Jim Varney
jvarney@mail2.quiknet.com
Sacramento, CA

      "Newton was the greatest genius that ever existed, and the most
       fortunate, for we cannot find more than once a system of the
       world to establish."      Lagrange.