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From: Alexandre E Eremenko (no email)
Date: Sun Oct 30 2005 - 14:48:47 EST
Dear John,
I am glad that there is a feedback on my postings
on the Bris sextant.
So I continue, simultaneously answering your questions.
Here are my (genuine, Bris-made, CP-sold) Bris angles.
There are 8 "Suns", not counting the real one.
3 bright, 4 dim, and one (No 8) very dim.
Row data from calibration observation on Jul 28, 2005,
Nx refers to the
Sun number x
from above, UL and LL are upper and lower limbs true altitudes. The
numbers are true
angles for given time and place, NOT corrected for refraction
and dip. Time and place were
determined by the on-board GPS. The elevation was
approx 6 feet, and the waves were substantial.
LL UL DIFFERENCE
N1: 10d04.5' 10d37.3' 32.8
N2: 12d29.5' 13d03.0' 33.5
N3: 20d39.1' 21d07.1' 28
N4: missed 23d33.3'
N5: 25d31.8' 25d58.9' 27.1
N6: 33d30.5' 34d00.2' 29.7
N7: missed 35d55.8'
N8: 45d53.2' 46d22.2' 29
The true Sun diameter was 31.6, according to Almanach.
Alex.
P.S. I have ONE more observation July 30 (of some limbs of some Suns)
to compare but I never reduced it. The problems were that
a) the sunny days/times were rare (North sea), and
b) I had to stand my watches at the rudder, and
c) I had to peel potato for the dinner, etc:-)
e) When the good weather was in my free time, I did ordinary sextant
observations with my SNO-T.
A.
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