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Re: On The Water Trial of Digital Camera CN
From: Marcel Tschudin
Date: 2010 Jun 19, 15:33 +0300
From: Marcel Tschudin
Date: 2010 Jun 19, 15:33 +0300
Just to give an idea on the sort of errors and their propagation for this photometric observation: Using my techniques and skill, I obtain: UL: 3600, 3601, 3600, 3600, 3600, 3600 (mean: 3600.2 +/-0.5) LL: 3515, 3515, 3515, 3515, 3515, 3515 (mean: 3515.0 +/-0.3) Horizon: 507, 507, 505, 507, 506, 506 (mean: 506.3 +/-0.9) As it happens very often, it's the horizon (and not of the sun) which scatters most. Resulting in: UL-Horizon: 3093.8 pixels (+/- 1 pixel, corresponding to +/-0.4 moa) LL-Horizon: 3008.7 pixels (+/- 0.9 pixels, corresponding to +/-0.3 moa) Estimated HS using 2 parameter arc-tan calibration formula having a StdDev of +/-0.2 moa, considering further the observational errors (H.E. and timing) of +/-0.6 moa results in: HSest (UL): 1160.2 +/- 0.7 moa, compared to the calculated 1159.3 moa HSest (LL): 1128.7 +/- 0.7 moa, compared to the calculated 1127.9 moa There can be several reasons for this observation to be slightly an outlier like e.g. the measurements not made the same way as the calibration was done or differences in refraction (inversion in the morning, whereas calibration was done during the afternoon). Marcel