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    Re: Solstice Sun Lines
    From: Brian Walton
    Date: 2018 Jan 5, 20:50 -0800

    Tracy,

    We’re talking the same language.  Here are some refinements.

    To reduce “dome correction”  try and get a body where the line of sight crosses the window at 90° near the middle.  The 747 has awful thick curves near the edges, the 767 a nice flat window.

    Definitely do Coriolis corrections.  Groundspeeds go up to 700 kts eastbound.

    The more single shots you do, the easier it is to recognize a good one and discard a bad one.  I used the side of the bubble, not the middle.  Backlash on the gearing might mean it’s better to refine always tracking up, or always down.  I don’t like tracking for 2 minutes;  nasty things creep up behind you.

    Oceanic routes often have legs following a parallel of latitude. Perfect, since Lat won’t change whilst you shoot for Long.  Running fixes aren’t necessary.  I discarded running fixes since my yacht calculator refused to accept ground speeds of hundreds of kts. I was able to fix this with my own programs in a Psion.

    Your accuracy is adequate.  Minimum time taken to get a fix is more important. Keep practicing; as with any artisan skill, you can forget how to do it. Love your PBY story.  I guess the R in CRJ means long trips are rare.  Winter westbound Pacifics are up there with your Catalina!

    Brian Walton

       
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