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    Re: Making an artificial horizon, and leveling thereof
    From: Gary LaPook
    Date: 2011 Jan 22, 18:12 -0800
    Since I made a larger water filled artificial horizon yesterday I decided to give it a try today and compare the accuracy of the water artificial horizon with the accuracy of the mercury horizon. I took three series of lower limb sun sights with my Tamaya Jupiter. I used the standard 4X40 scope for two series, one of 5 shots which had a sigma of 0.4037 and the second series of 6 shots that had a sigma of 0.0752. Combining these 11 shots resulted in a sigma of 0.3605. I took the third series using the inverting scope from my SNO-T (which fits in the Tamaya scope mount) to see if the higher magnificaton would produce greater accuracy. I took  5 shots which had a sigma of 0.4266 so was no better than with the 4X40 scope.

    A couple of days ago I took similar sights with the mercury horizon. Using the 4X40 scope for 5 shots resulted in a sigma of 0.4219 and with the inverting scope for 18 shots resulted in a sigma of 0.3308.

    Based on these experiments it doesn't appear that there is a significant difference between the two scopes or between the two artificial horizons when shooting the sun. Off course the mercury is better for dim stars.

    BTW, is was 73° F here today in southern California so I didn't have any problem with the water freezing in the artificial horizon.

    --- On Sat, 1/22/11, Gary LaPook <glapook@pacbell.net> wrote:

    From: Gary LaPook <glapook@pacbell.net>
    Subject: [NavList] Re: Making an artificial horizon, and leveling thereof
    To: NavList@fer3.com
    Date: Saturday, January 22, 2011, 11:17 AM

    I have found that it works best to place the artificial horizon on the ground and position a chair which keeps you in the correct alignment with the horizon and the sun. It is even better if you can position your head against the chair back to keep you head in a fixed position.

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