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    Re: JPL ephemeresis and Nautical Almanac - speed of light question
    From: Peter Monta
    Date: 2018 Apr 3, 08:51 -0400
    Hi Rafal,

    The reflected / emited light and time needed to reach the observer should be taken into account. Am I correct?

    Yes.  Generally there's an iterative process to solve for the apparent position.  It converges quickly.

    This page from Skyfield has some discussion in the "Astrometric position" section:

    http://rhodesmill.org/skyfield/positions.html

    For your application, Skyfield might be a convenient option: it takes care of all the JPL ephemeris low-level handling (and even downloads the files for you).  If you want something lower level, USNO's NOVAS or JPL's SPICE or Orekit might be good.  The documentation for all these generally goes into the ins and outs of reference frames, positions of various flavors and the pipelines involved, and hazards.  There's also the Explanatory Supplement book (supplement to the Astronomical Almanac).

    Cheers,
    Peter

       
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