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    Re: Lunar with Davis MKIII Sextant?
    From: Bruce Cutting
    Date: 2019 Feb 20, 16:21 -0700

    It would be an interesting adventure (to have someone else take).  I have
    used and gotten reasonable results with a Davis MK 25.  BUT - I usually
    took multiple measurements and averaged - you may not have time to do that
    for LD or else the calculations (LD at different times) would become
    complex (not sure if averaging is applicable here)
    Several precautions:
    1) Allow the MK25 to come to ambient temperature
    2) Be aware that the MK25 has a large backlash and tends to bind depending
    on temperature.
    3) ALWAYS measure the LD and IE from UPscale to DOWNscale - otherwise
    backlash will make your measurements very inaccurate.
    4) If you go passed the coincident point - do NOT reverse direction
    without going back at least an arc-minute or so to eliminate problems
    related to backlash.
    Good luck
    On Wed, February 20, 2019 10:31, Herman Dekker wrote:
    > After reading about Lunars. I am interested in this subject, but the
    > available instruments are doubtfull. I am surrounded here with mountains.
    > If I want to do a lunar the objects must be above 12°.
    > From Franks easy Lunars info I understood minium height is 15°so thats no
    > problem. For the heights I can use the A-12 bubble sextant, but for the LD
    > only the Davis MKIII is available. That sextant has a scale division of
    > 2', with a magnifier glass, you can read and interpolate to 1'.
    > Is that possible for a Lunar if you have lost accurate time, or is it a
    > useless excercise. Regards,
    > HermanD

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