NavList:

   

Reply

Wolfgang,

well, if Freibeger sold the sextant with such certificate,
then probably this is admissible by their standards.
Independently of this, looking at various sextant certificates
on e-bay for many years, I noticed that Freiberger sextants
frequently show relatively large corrections.

I agree: it looks like an excentricity error.
Have you tested the sextant in practice?
It can give good results with corrections applied.

The best test I know (short of a sophisticated equipment) is
taking Sun-Lunar distances, and then comparng them with Frank's
calculator.
About a week of daily observatins in good weather permit you
to check most of the arc.

Alex.

On Sun, 15 Apr 2012, Wolfgang Hasper wrote:

>
> Jean-Philippe and Alex,
> Here's the table from the sextant case (translated :o))
>
> Angle ?	Correction ''
> 0		0
> 10		+3
> 20		+13
> 30		+18
> 40		+25
> 50		+28
> 60		+36
> 70		+38
> 80		+46
> 90		+52
> 100		+50
> 110		+51
> 120		+48
>
> It belongs to  Freiberger Trommelsextant No. 080103 (w.
> full sight mirror), bought early 2009, so likely
> manufactured 2008.
>
> plotted corrections are fairly well resembling a sine
> curve, which is why I assume eccentricity as the main
> source of error.
>
> Any other ideas?
>
> Wolfgang
>
>
>
>
>
> : http://fer3.com/arc/m2.aspx?i=119080
>
>
>

   

Reply