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moon orientation

I am a cognitive psychologist investigating the moon illusion (the moon looks much larger on the horizon than high in the sky). In an experiment I am planning, I ask people to judge the orientation of the moon relative to the horizon. To see how well people can do the task, I need a way of knowing the true relative orientation of the moon. Using SkySafari 5 on my Mac, I can generate an image of the moon and can compute the relative orientation (compared to some arbitrarily defined standard orientation). However, my method is clumsy and I wonder if there is some algorithm that can provide the needed information more directly. Also, I wonder in general how much I should trust the images generated by SkySafari5 with regard to the perceived orientation of the moon. 

Any advice would be welcome.


  • 1
    Bill Tschumy


    I have moved your post to the SkySafari > General Astronomy forum.  You posted in the Form Feedback subform which is not really appropriate for your question.

    You can certainly trust the orientation displayed by SkySafari.  We take into account all the main factors that affect orientation.

    As far as this being clumsy, unfortunately there really is no simple algorithm to determine this.  

  • 0

    Just for kicks I created this animated GIF showing the orientation of the moon on the horizon at moonrise over a period of 29 days.

    Kind of neat.

    (Hopefully an animated GIF will play on this forum, it did in the post preview window. If not then... never mind.)


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