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Robert,
The symbol ^ represents power. So L^2
means L squared (multiplied by itself).
Here is the same formula in words:
Chauvenet:
Error in seconds equals
negative 2 times sin1" times (error in perpendiculatiry, squared) times
tangent of one quarter of the angle.
Hope this helps.
I bought Chauvenet in some web book store for much less
than $300. I don't think I payed more than $50 for the
set of two volumes in excellent condition.
(I don't remember what the exact price was, but I would
definitely not buy it for more than $50, because my
university library has it, and the library is next to
my office. So yesterday I used the library copy to reply
your message quickly:-)
Alex
On Mon, 17 Apr 2006, Robert Eno wrote:
>
> Thanks Alexander
>
> Quick question:
>
> Does the ^ symbol represent multiplication?
>
> I am having a bit of trouble following the sequence of calculations in the
> formula.
>
> Any chance of your scanning in that particular page and sending to me?
>
> I've always wanted a copy of Chauvenet but the $300 plus price tag deters
> me.
>
> cheers,
>
> Robert
> ----- Original Message -----
> From: "Alexandre E Eremenko" <>
> To: <>
> Sent: Monday, April 17, 2006 2:21 PM
> Subject: Re: Error of Perpendicularity
>
>
> > Dear Robert,
> > The only book I know that contains a COMPLETE
> > theory of sextant is Chauvenet. (I am sure that there
> > are others, but this is really complete, very concise,
> > and written in good English:-)
> >
> > In particular, on p. 115 (vol. 2) the following formula
> > is derived:
> > Err=-2 L^2 sin1" tan(h/4),
> > where Err is the resulting error, in seconds
> > L is the deviation of your mirror from
> > perpendicularity (in seconds) and h the angle you measure.
> >
> > In more modern notation this becomes:
> > Err=-0.00057 L^2 tan(h/4)
> > where both Err and L are in minutes now.
> >
> > For example, if L=5'
> > Then Err=0.008 or 05", which is completely negligible.
> >
> > Now, according to SNO manual, you can adjust this mirror
> > (using special factory-supplied visors in place of dominoes)
> >
> > That's why visual adjustment (without dominoes) is OK too.
> > Two years ago there was a large discussion on the list about
> > how exactly to do this adjustment, and the general conclusion
> > was that dominoes (or visors) are only recommended for sextants
> > with front-silvered index mirros.
> > For back silvered mirrors, the usual eye method is OK.
> >
> > Alex
> >
>
