RE : [NavList] Re: TRANS ATLANTIC
From: Mike Burkes
Date: 11 Nov 2012 05:59
Hi folks,regarding Altair site and using Hs 56 58.4:My initial "pinwheel" fix resulted in the three stars until I realised intercept was incorrectly plotted towards rather than away!
Corrected fix eliminating Alpheratz,yielded 42 01.5 N 34 04.0W close to Greg's.
Mike Burkes
626-833-1521
*******
From London Heathrow on Nov 11th, 2012
Hello Mike and Hello to all,
Thanks for your last post, Mike.
If eliminating Alpheratz on my side too, I am left with the following 3 azimuths and intercepts :
ALPHERATZ i = -5.8 (A) NM , Z = 083°0 (REMOVE)
ALTAIR i = -2.1 (A) NM , Z = 184°0 (KEEP)
KOCHAB i = +0.2 (T) NM , Z = 338°4 (KEEP)
MOON UL i = +1.5 (T) NM , Z = 121°6 (KEEP)
Observed position has now become in Azimuth 060° and at distance of 3.4 NM from DR Position, with a LOP's dispersion of 0.2 NM, which would be excellent.
At the Time (is it 17:56:20 LT ?) when DR position is N 42°00'0 W 034°10'0 , the Observed Position would be shifted 1.7 NM to the North and 3.0 Miles to the East (i.e. 3.6' of Longitude to the East) and would become N 42°01'7 W 034°06'4 (again very
close to previous determinations from Greg and Mike).
While I am relying on computations (almost) throughout, the main reason for the differences between our resulting fixes would probably come from the fact that Greg and Mike you seem to get your own positions through reading them from your hand-plotted charts.
HOWEVER ...
... HINT ! As discussed in the past, there should be NO reason to eliminate Alpheratz unless for excellent reasons which I have not read about in this thread. I keep advocating that our position should rather remain (close) to our previous determination, i.e. N 41°59'7 W 034°13'4 .
The only "key" to progress into a reliable knowledge of each individual LOP Quality here would be to know a GPS position and time around the time of observations, from which we could accurately time carry backwards/forwards in time the accurate Observer's position at the time of each specific sight.
ANY SUCH KNOWN GPS
POSITION AND TIME ON FILE, KEVIN ?
Same question also holds for your OCT 22nd, 2012 Fix.
Best Regards to all
Kermit
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