# NavList:

## A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

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Re: "100 Problems in Celestial Navigation"
From: Joel Jacobs
Date: 2004 Apr 4, 19:14 -0400

```Renee,

The method I used was to average the time and Ho readings of three sights,
and only plot one LOP for each body. Having the right calculator simplifies
the process. I also made all the plots in the logbook using the previously
discussed method.

Joel

----- Original Message -----
From: "Renee Mattie"
To:
Sent: Sunday, April 04, 2004 4:24 PM
Subject: Re: "100 Problems in Celestial Navigation"

> I want to thank everybody who chimed in on this thread
> about Leonard Gray's 100 problems, cocked hats, and
> sight reduction methods.  I have found it edifying.
> I would be happy to compare my results to those
> obtained by others.
>
> I have a couple of questions:
> + Is there a copyright issue to posting the text of
> one or several of these problems?
>
> + What about sight averaging?  I have read recommendations
> to plot the altitudes of three sights taken in rapid
> succession and use an altitude/time average, or to find
> a best-fit line of the proper slope.  Here, folks seem
> to prefer to plot the LOPs from all three sights.  I suppose
> this gives you some notion of the size of the error in the
> individual sights.  I find it difficult, when examining the
> result, to decide where to mark an MPP, which is, I guess,
> the point.
>
> Leonard Gray does not give any notion of how close he feels
> the student should come to his answer.
>
> Renee

```
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