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be careful too of the angle unit, radians versus degrees.

On Jan 5, 2011, at 10:27 AM, Apache Runner wrote:

> Maybe I am misunderstanding.   Let me look at the formula again -
> on that website you had, there was a crude figure of merit for what
> I thought was refraction that was 1.75 moa * sqrt(h)   where h is
> in meters.   It seemed to be for refraction and it gives 40 moa if
> I plug into it.
>
> Where did you get 6 moa from?
>
>
>
> On Wed, Jan 5, 2011 at 10:17 AM, Marcel Tschudin
>  wrote:
> John, you wrote:
> > Both the dip and the refraction are in the 40 arc minute region
> for a 500 m
> > peak, ....
> Could there be a misunderstanding? From a 500m high peak the horizon
> has a geometrical dip (without refraction) of about 40 moa. The
> refraction increases this geometrical dip by e.g. 6 moa leading to an
> observed dip of e.g. 46 moa. In this case we deal with the
> "terrestrial" refraction which is considerably smaller than the
> "astronomical" refraction since in the "terrestrial" case the length
> of the ray path through the atmosphere is much shorter.
> Marcel
>
>
>
>
>
>
> --
> Keeping up with the grind

   

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