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    Re: Daytime Venus Rising Dip Short
    From: Hewitt Schlereth
    Date: 2012 May 4, 13:01 -0700
    Gary, how large a bubble do you use? For the sun with my Mk IX-A I've been using a bubble about 50% larger than the sun. This leaves a narrow black rim around the sun which helps me keep it centered within the bubble. My intercepts with the averager are usually around 1-2 moa. Double that without the averager.

    Hewitt 

    Sent from my iPad

    On May 4, 2012, at 12:48 AM, Gary LaPook <garylapook---.net> wrote:

    I took three daytime Venus observations with my MA-2 bubble sextant. I had never been able to spot a planet with my bubble sextants before. The secret for daytime planet observations is precomputing the altitude so that you can set it on your sextant and then sweep the approximate azimuth, This goes for using a marine sextant too and I have been able to see Venus in my Tamaya before.

    The MA -2 produced very good results.

    April 16, 2012 local date.

    17:42:42 local time, 00:42:42 Z, April 17, 2012

    From the Navy website:

    Celestial Navigation Data for 2012 Apr 17 at  0:42:42 UT           
                                                                                   
                     For Assumed Position:  Latitude    N  34 16.6                 
                                            Longitude   W 118 54.0    
                                 GHA                    DEC                    Hc                       ZN            
    VENUS      147 04.8   N26 30.2   +64 34.6   259.9  |   -0.5   0.3   0.1  -0.1
    :Hs 64 38
    IC       -  2
    Corr       0  (-0.1)
    Ho  64 36
    Int 1.4 T

      Celestial Navigation Data for 2012 Apr 17 at  0:43:12 UT  
    VENUS 147 12.3 N26 30.2 +64 28.5 260.0 | -0.5 0.3 0.1 -0.1

    Ho 64 29.5
    Int 1.0 T

    Celestial Navigation Data for 2012 Apr 17 at 0:43:49 UT

    VENUS 147 21.6 N26 30.2 +64 20.9 260.1 | -0.5 0.3 0.1 -0.1

    Ho 64 21

    INT 0.1 T

    I suppose that I should say the intercepts were 1 T, 1 T
    and zero since I can't measure to one-tenth of a minute.

    I'm pretty happy with these results.

    gl






    --- On Thu, 5/3/12, Alexandre E Eremenko <eremenko---.edu> wrote:

    From: Alexandre E Eremenko <eremenko---.edu>
    Subject: [NavList] Re: Daytime Venus Rising Dip Short
    To: NavList@fer3.com
    Date: Thursday, May 3, 2012, 3:45 PM


    11 am is great.
    I don't have a horizon within 100 miles of me, short or long, but will try
    tomorrow with
    my air sextant:-)

    Alex.

    On Thu, 3 May 2012, Greg Rudzinski wrote:

    >
    > The PDT time 11:00 am. Lat 34* 10.4' N Lon 119* 13.8' W.
    > Example: 5/3/2012
    > UT 18:02:49  Venus  Hs 33* 45.3' Dip Short correction -23.7' (H.E. 6.5 ft. horizon .157 NM) I.C. 0.0
    >
    > Intercept 1.0' A  Azimuth 76.8*
    >
    > Greg Rudzinski
    > ----------------------------------------------------------------
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