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The shot pamphlet that I got with my first Davis Plastic sextant said
it exactly that way - bought the sextant in 1982 as I remember

Cheers!

Bruce

Quoting Frank Reed :

> There are a couple of little issues here. First, you have to decide
> when "culmination" occurred (using the narrow definition of
> culmination as the time of maximum altitude). As Greg noted, this
> involves sights before and after local noon. There are various ways
> of combining and processing these sights. Next, you have to remember
> that culmination, in this narrow sense, may not be the same as
> meridian passage. This is especially true for Moon culminations, but
> even for the Sun there is an offset. You need to apply an adjustment
> for vessel motion and changing declination, which really amount to
> the same thing. From here we have the GMT/UT of the body's actual
> meridian passage.
> Since meridian passage always occurs when a celestial object has the
> same longitude as the observer, we only need the longitude of the
> subStar point for that celestial object at that instant of UT. And
> the longitude of the subStar point is the GHA! GHA **is** longitude.
> So finally, yes, that's the quick, modern way to do it. Take
> whatever steps are needed to determine the UT of the body's meridian
> passage. Then simply work out from almanac data the body's GHA at
> that instant of time. *Its* longitude is *your* longitude.
> So why don't books on celestial navigation make this simple process
> more clear? That's a question worthy of some discussion and
> speculation!
> Frank Reed
>
> [plain text auto-generated]
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