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    Re: Fine adjust a Davis Mk 3
    From: Greg Rudzinski
    Date: 2016 Mar 26, 20:36 -0700

    Internet at the marina is slow today so no pics of Davis MK 3 solar film mods :( A total of 28 Sun observations were made today with the Davis MK 3 using an artificial horizon. The altitudes observed ranged between 90° and 20°. Intercepts were all toward between 1.4' T and 8.2' T. Index error was checked and set to zero before each observation. An arc error of 4' will be subtracted from each altitude on the next set of Sun observations. This should tighten intercepts up to + or - 3'. Not too shabby for a plastic cheapy.

    Greg Rudzinski

    From: Greg Rudzinski
    Date: 2016 Mar 26, 17:20 -0700

    Frank,

    Ha ! I just added a Davis MK 3 to my clutch of sextants and am at this very moment working out how to improve performace on this model. The first thing done was to add solar film filters which aids in index error determination showing a very sharp Sun. An artificial horizon is being used for accuracy testing. A separate post will show working notes, modification pics, and conclusions on how to squeeze out a little bit more accuracy on the Davis MK 3.

    Greg Rudzinski

    From: Frank Reed
    Date: 2016 Mar 25, 23:01 -0700

    The plastic Davis Mk 3 sextant is an incredibly basic, yet fully-functional, navigation-quality sextant. You could cross oceans with one of these things. They look flimsy, distractingly cheap, but as proper instruments of reflection they do work, and they are capable of measuring altitudes within three or four minutes of arc with just a little care in the observation process.

       
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