NavList:

   

Reply

--- Lu Abel  wrote:

> I suspect very strongly the arrangement of data was based more on
> the needs of the computational algorithms used to compute the tables
> than for convenience of the navigator.

Possible... but I've still got to ask the obvious question: Assuming
they were using the same formula that we use to solve the navigational
triangle today (and I don't know if that's the case or not), it doesn't
seem like it would be any more difficult to solve a series of them
(i.e. a table page full) with any one of the variables held at a
constant value vs. another of them (i.e. holding the LHA value constant
for a page as 229 does vs. holding latitude constant for a page as 249
does).

--
GregR


> Greg R. wrote:
> > I've never figured out why 229 is LHA-based (instead of being
> > latitude-based as 249 is). Since you're going to use the same
> assumed
> > latitudes for a fix (or I guess maybe nearby latitudes, if a lot of
> > time passes between fixes) why should you have to flip to a
> different
> > page in the tables for each fix?
> >
> > Might have something to do with the computer program used to
> generate
> > the tables, but I'd also assume that the output could be setup in
> > whatever format was desired by the end-user.
> Greg:
>
> Look at the prefatory material in 229.  The tables were developed
> half a
> century ago using IBM 1401 computers!  (There's one under restoration
> in
> the Computer History Museum down the road from me in Silicon Valley).
>
> 1401s have way less compute power (and memory) than your cell phone.
> So
> I suspect very strongly the arrangement of data was based more on the
>
> needs of the computational algorithms used to compute the tables than
>
> for convenience of the navigator.
>
> Lu Abel
>
> >
>


--~--~---------~--~----~------------~-------~--~----~
Navigation List archive: www.fer3.com/arc
To post, email NavList@fer3.com
To , email NavList-@fer3.com
-~----------~----~----~----~------~----~------~--~---

   

Reply