NavList:

RE : [NavList] TRANS-ATLANTIC CROSSING
From: Kevin Coulombe
Date: 22 Oct 2012 15:51
BODY: stars

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From Kermit : solving here-under your fix, Kevin. Hopefully I correctly "decoded" your data. Computations performed with TT-UT = 68.0s

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Date: 22OCT2012 LT - WATCH TIME: as per body - ZD: +4 - WATCH ERROR: 5S FAST

SEXTANT - FPM DRUM SEXTANT / AP MOLLER COMPANY ISSUE / CURRENT BRIDGE EQUIPMENT
4X40 MONOCULAR - RESIDUAL ERRORS +5” AT 20 DEGREES - INDEX ERROR 0.8 OFF THE ARC

HEIGHT OF EYE 30 METERS - BAROMETER 1013 - AIR TEMP 15C

DR L 41 00 N Lo 066 30W Note from Kermit : this DR position is assumed to be the one valid for LT = 18:12:05 (Hour of the MIRFAK Observation. If it were not the case, the final observed position for the chosen LT remains unchanged anyway). Course 076 T Speed of Advance 21.2 kts .

BODY
MIRFAX
WT 181440 UT = 22h14m35.0s
Hs 18-40.2 H = 18°41'0 Corrected for Index error but NOT for "residual error at 20°" i MIRFAK = +1.2 NM (T), Z Mirfak = 038°9

ALTAIR
WT 181210 UT = 22h12m05.0s
Hs 58-06.5 H = 58°07'3 Corrected for Index error but NOT for "residual error at 20°" i ALTAIR = +2.7 NM (T) Z ALTAIR = 180°8

ARCTURUS
WT 181623 UT = 22:16m18.0s
Hs 15-57.3 H = 15°58'1 Corrected for Index error but NOT for "residual error at 20°" i ARCTURUS = -6.9 (A) Z Arcturus = 281°8

MOON
XXXXX
XXXXX
Technical error: I should have shot this body late in civil twilight as by the time I shot the moon the horizon was too dark.

OBSERVED POSITION from DR in Azimuth 116° at a distance of 6.9 NM
LOP's Dispersion : 0.3 NM (excellent)

At 18:12:05 LT , DR Position : N 41°00.0' W 066°30'0 , and
Observed position : 40°56'9 W 066°21'8

Note : this position is close from the one derived by Greg : N4°57' W066°23' probably for that same 18h12m05s LT.

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Thank you very much Kevin, for giving us the opportunity of crunching real world numbers. The quality of your fix seems really good.

BTW, what was the GPS fix at that time, or any time close to 18h12m05s LT ? If you have it on file (both Position and Time), then you could quite reliably "grade/rate" the quality of your CelNav Fix from GPS position, especially as far as your Observed Longitude is concerned. Latitude should be no problem.

Best Regards to all

Kermit
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