NavList:

Lu wrote:

> I've never seen the formula expressed with a dlo, but I suspect it's
> simply the difference between the observer's longitude and the body's
> GHA without worrying about who is east of whom.  Simplifies the picture
> of the spherical triangle and makes it easier to understand.  But if one
> is doing sight reductions with a calculator, why insert an extra step
> (changing a large LHA to a small dlo)?  Every extra step is a potential
> source for error.  A calculator is quite happy to calculate (and get the
> correct answer) using LHA!

Excellent point, and I have never seen it call for dlo unless using it to do
great-circle-route calculations.

When answering Guy, I did notice I had given some misinformation (been doing
reductions with the calculator too long) ;-)

"229 table errors for figuring d, v,..." put the tables in the wrong book!
v and d correction will be in the "Increments and Corrections" section of
the almanac Guy. "Increments and Corrections" is essential time-to-arc.

The second "d" correction is in 229, and is used to adjust the tabular value
for Hc.  Why the same letter for two different calculations?  I don't know.

Bill


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