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Unfortunatley the table is un-readable. I try to put it together with the
text to my mail [6023] as an attachment.
Kent N
----- Original Message ----- 
From: "KENT AE NORDSTRÖM" 
To: 
Sent: Monday, August 04, 2008 5:41 PM
Subject: [NavList 6023] Re: My first Lunar


>
> Frank wrote [5988]: You found deviations as large as 0.6 minutes or arc in
> the clearing with a
> standard deviation of 0.3 minutes. That's a lot! Though I certainly can't
> guarantee it, I believe that my clearing results are accurate to 0.05
> minutes of arc so I would say that you still have some things to fix. Even
> in the year 1790, a discrepancy of 0.6 minutes of arc in clearing a lunar
> would have been counted as "too large" except as a rough approximation.
>
>
>
> The results from my test cases with my input data into Frank's prediction
> model [5932] were as in columns 2-3 below. All data 1-8 are in minutes of
> arc directly read out from Frank's model.
>
>
>
> I still claim that my own LD prediction model is rather precise well aware
> of that I use old-fashioned methods. My  results with the same input data,
> except for Jeremy's first lunar - case 8, as per above in my own model
> give
> errors in LD as per column 4. Column 5 is just a conversion to compare
> figures in arc min with what I got from Frank's model. So the relevant
> comparison is between column 2 and 5 :
>
>
>
>
>
>      Case
>     Frank's error in LD
>     Frank's error in longitude
>     My error in LD
>
>      In arc sec
>     My error in LD in arc min
>
>      1
>     0'
>     1'
>     -5,5"
>     -0,092'
>
>      2
>     0,6'
>     19'
>     -2,1"
>     -0,035'
>
>      3
>     -0,3'
>     10,3'
>     5,5"
>     0,092'
>
>      4
>     0,3'
>     9,6'
>     -1,5"
>     -0,025'
>
>      5
>     0,1'
>     3,3'
>     0,06"
>     0,001'
>
>      6
>     -0,2'
>     5,5'
>     -2,3"
>     -0,038'
>
>      7
>     0,4'
>     11,1'
>     -0,5"
>     -0,008'
>
>      8
>     0,1'
>     1,8'
>     -
>     -
>
>      Mean
>     0,125'
>     7,7'
>     -0,91"
>     -0,015'
>
>      Std. Dev.
>     0,3'
>     6,0'
>     3,3"
>     0,055'
>
>
>
>
> Frank's comment that an error of 0,6' was to large in 1790 can be
> questioned. I would say that navigators then were likely not unhappy to
> find
> longitude within 15-20 M (0,5-0,7 min of arc in LD). The errors in my LD's
> are referred to test cases taken from text books. You can of course always
> ask what is correct.
>
>
>
> Kent N
>
> ----- Original Message ----- 
> From: 
> To: 
> Sent: Sunday, August 03, 2008 3:02 AM
> Subject: [NavList 5988] Re: My first Lunar
>
>
>>
>> Kent, you wrote:
>> "I have now made a comparison between Frank's model and mine and here are
>> the results. In all cases I have used my own way to compensate for
>> oblateness/flattening. By using my data in Frank's modell error in lunar
>> and
>> and error in longitude are read out.
>> [...]
>> So it seems to me that my model is rather good. The deviations are
>> probably
>> that I model e.g. refraction and oblateness/flatness in a different way
>> from
>> Frank."
>>
>> You found deviations as large as 0.6 minutes or arc in the clearing with
>> a
>> standard deviation of 0.3 minutes. That's a lot! Though I certainly can't
>> guarantee it, I believe that my clearing results are accurate to 0.05
>> minutes of arc so I would say that you still have some things to fix.
>> Even
>> in the year 1790, a discrepancy of 0.6 minutes of arc in clearing a lunar
>> would have been counted as "too large" except as a rough approximation.
>>
>> -FER
>>
>> >
>>
>
>
>
> >

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