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    Re: Stellarium, refraction, HP
    From: Paul Hirose
    Date: 2020 Jan 14, 11:31 -0800

    On 2020-01-12 17:46, Jim Rives wrote:
    > I think this may have been easier if I actually took altitudes for the sun 
    and the moon, but there was no horizon.  I'd love to be able to use 
    Stellarium, or some other tool, to get the altitudes so I can mess with this 
    frequently and actually get fluent it the methods.
    If you can run a Windows app, my Lunar program can generate simulated
    altitude observations of either limb (or body center), including
    refraction (corrected for temperature and pressure) and dip if desired.
    For example,
      28°33.60' computed unrefracted center altitude
        -16.26' unrefracted semidiameter
          1.65' refraction
      28°18.99' apparent lower limb altitude
          0.00' dip
      28°18.99' apparent altitude + dip
    152°22.92' predicted azimuth
    I did not turn on the dip feature because the computation was run for my
    location, where the height above sea level would result in an immense
    dip value!
    Expected lunar distance is also computed, which is a big convenience if
    you shoot a star lunar since the sextant can be preset. It also predicts
    the position angle (with respect to the zenith) from the Moon to the
    other body. That gives the sextant orientation (about the line of sight
    to the Moon) to bring both bodies into coincidence.
    The installer is just a zip file which you extract into any convenient
    folder on your system. Default behavior is that it creates a new folder
    which contains all the application files. Other than that, it does not
    modify your system. If you want a shortcut to the executable on your
    desktop, you must make it by hand.
    As installed, the program cannot do anything useful. It needs a JPL
    solar system ephemeris, and one is not included. It's my belief that
    users should learn to do that themselves. You need only decide which
    ephemeris you want, download a couple ASCII files (one is the ephemeris
    itself, the other a "header"), and transform the files into a binary
    ephemeris. A function built into my program does that last step. There
    are instructions on the web site.
    The program is really designed for my own needs, but as a courtesy I
    offer it free to the public.

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