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From: George Huxtable (no email)
Date: Fri Aug 13 2004 - 16:07:29 EDT
Guus Dekker asked-
>What is wrong with my computation about sunrise at Sao Paolo at july 18
>2003(three)
>lat: 24-20 S long: 47 W
>
>Nautical Almanac 2003
>
>20 6.11
>
>24,20 X
>
>30 6.27
>------- --------
>10* 17 m Dla = 24.20 - 20 = 4* 20'
>
>Table 1 page xxxii
>10-4.20-4.30-17-15 --- corr. = 7 m X= 6.11 + 7 =
>6h 18m
>
>
>
>
>long: = 47*
>47*/15* = (ZD)3 x 15* = 45*
> ---------
>
> Dlo 2* conv. arc to time page i
>2--- 8 m (w=+)
>
> ----------------
>
>SUNRISE
>6h 26m
>
>(my navigator light 4.1. prog tells me the sunrise = at 6h 50m) ??????
=============
Response from George-
Well, I have here a Nautical Almanac for 2001, not 2003. But on the same
day of the year, sunrise and sunset times aren't going to vary much from
one year to another.
It looks to me as if Guus Dekker has taken his times, not from the Sunrise,
but from the "end of Civil Twilight" column. This precedes sunrise by
about 25 min, and gives the time when the Sun is about 5deg below the
horizon.
George.
================================================================
contact George Huxtable by email at , by phone at
01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
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