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    NA "v" correction & mercury observations
    From: Jeremy C
    Date: 2011 Jan 16, 07:06 EST
    You will find the nuance of my writing to cover that very topic Kermit.  That is why I said it is "applied" rather than "added."   "v" is nearly always positive, but sometimes is negative for the planets.  Venus at this very moment, has a negative "v" correction.   It is -0.3 for today's (Jan 16) bonus Exotica exercise (although due to it being only 8 minutes past the hour, it didn't affect GHA).
     
    For those who don't know, the "v" correction is used to save space in the NA.  If you notice in the Increments and corrections page, the column isn't labeled "Sun" it's "Sun and planets"  Since the planets move at a slightly different rate there is an additional correction to be applied to get the proper GHA.  The moon also has a "v" correction that allows for more accuracy because the table in the I&C pages is for a "standard moon" but since the moon's rate of change for GHA is variable, you need to apply a fairly sizable "v" correction that varies each hour. 
     
    Mercury LOP's and/or Azimuths were shot on January 7,8, & 9 this month.  I would have gotten one on the 10th but the horizon was terrible at 109 degrees so the planet disappeared before the horizon appeared even remotely distinct.  Peter's spreadsheets and my starpath calculator allowed me to actually get LOP's and correct for the azimuth as I shot them instead of having to ask for data as I did in 2009.
     
    I just hope that shooting Mercury doesn't make me mad as a hatter. ;-)
     
    Jeremy
     
     
     
    In a message dated 1/15/2011 3:52:29 P.M. Central Asia Standard Time, antoine.m.couette{at}club-internet.fr writes:

    RE : http://www.fer3.com/arc/m2.aspx?i=115290
    [NavList] Re: help with sun sights
    From: Anabasis75---com
    Date: 15 Jan 2011 03:00

    Hello Jeremy,

    You wrote :

    QUOTE

    " 5) The "v" correction is similar to the "d" correction but is applied to the GHA of the body. You must use the number at the bottom of the column for all non-lunar bodies. "

    UNQUOTE

    May I comment as follows ?


    Yes ! And if I remember well, the "v" correction is ALWAYS POSITIVE for the Navigational Planets, with one (exotic!) exception : VENUS for which it can be negative.
    I would also guess that the same holds for Mercury too ... but limited interest here.


    Best Regards

    Kermit


    Antoine M. Couëtte


    My following question is a bit late, I know ... since Mercury was beautiful in the morning sky just one week ago (i.e. by the 08th of January 2011), but ...

    ... do you belong to the "Mercury Shooters Club" ? :-))

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