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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Visit to Freiberg
From: Alexandre Eremenko
Date: 2005 May 30, 04:47 -0500
From: Alexandre Eremenko
Date: 2005 May 30, 04:47 -0500
Bill, The index correction is +0.6', not -0.6. This is not surprising because the master was adjusting both mirrors. The most plausible theory is that there was something in the drum, some dirt or old oil, or whatever, and when the master was adjusting the backlash (or whatever he adjusted in the drum, this thing whatever it was, was removed from the worm-arc connection). Of course I should had asked them to disassemble and clean the drum inside. But this thought did not occur to me: I thought that it was the arc error. I will take my sextant to Cassens-Plath and show it to them. I don't know whether they know how to adjust Friberger-type trommels and have instrument for this but I will ask. The idea to ask them to issue another certificate also occured to me: I think it will be interesting to compare both certificates then, and maybe the pleasure is worth another 60 EU :-) A. P.S. So far all my measurements are nearly perfect. Yesterday did more Sun/art horizon with error never exceeding 0.1'. It's harder with the stars. They are not visible until after 11 p.m. (because I am at 54 degrees N), and there are always fast moving clouds here. And I did not take my starfinder, not speaking of the globe, so have difficulties identifying the stars in the gaps between the coulds. On Sun, 29 May 2005, Bill wrote: > Knowing your quest for accuracy, and the unexplained shift from calibration > at 0d IE to -.6 IC, any thoughts of having the instrument calibrated again > Cassens and Plath?