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    Re: Working lunars from calculated altitudes.
    From: Brian Whatcott
    Date: 2002 Mar 31, 09:47 -0600

    At 12:08 AM 3/31/02, Bruce Stark wrote:
    >In a message dated 3/29/02 4:12:37 PM, george{at}HUXTABLE.U-NET.COM writes:
    ><< It's clear that this long-winded reiteration process does not lend itself
    >to hand-calculation, though a computer would do it in a twinkle.
    >If anyone (and here I am thinking particularly of Bruce Stark) can suggest
    >a way around this problem, I would be pleased to hear about it. >>
    >Bruce responds: Well, I had my first go at it this evening. Calculated the
    >altitudes for that first set of Pollux distances taken Monday night, using
    >GMT 04:00:00. That's three-quarters of an hour early of the truth. Pollux's
    >altitude came out O.'4 different from the that gotten with the correct GMT.
    I want to tell the list how interesting I am finding this effort to use a
    time insensitive method to find the time, and specially how some actual
    observations were given, and 'gardened' for out riders.
    I will admit, I had the sincerest doubts about the wisdom of discarding two
    out riders because they 'looked wrong'. I seem to remember that gardening
    for outriders is not in itself suspect. But the procedure if I recall was
    to pick out values on the tails of a distribution - and from both sides.....
      Anyway, I sang along by finding a least squares fit to ALL the
    observations, and agreeing with George on the result of picking off the two
    wild out riders in one dataset offered on the list.    So I should not
    complain at what works.
    I had a moment of weakness I will admit, to working on the kind of slope
    estimator George had suggested as a function of altitude and latitude etc.,
    but the weakness passed in time, thank goodness!  :-)  particularly as I
    enjoy using the non linear regression package NLREG. It  is an obvious and
    widely used tool for making a good shake at estimating weights for factors
    affecting a variable in this way.
    Brian W
    Brian Whatcott
       Altus OK                      Eureka!

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