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    Re: Jupiter in daylight and micrometer test
    From: Frank Reed
    Date: 2016 Apr 19, 10:35 -0700

    Stan, that's similar to my experience. Myself, from here on the island in Narragansett Bay, I could not find Jupiter at 5pm with binoculars but within half an hour it was visible --a nice clean disk. It became much more prominent as the Sun fell lower in the sky. Half an hour before sunset I could just make out Jupiter without any optical aid. By fifteen minutes before sunset I could see it clearly without optics. And of course all of this was possible only because the Moon provided a fixed point for the eye. To see stars and planets in daylight, we are fighting against the "visual saccades" --those very rapid, small-scale movements of the eyes' point of focus that we are normally not aware of. Without some fixed point to "hold onto" visually, it is nearly impossible to see Jupiter in daylight at sea level.

    In June, there may be an interesting opportunity to bring sky polarization into play. Jupiter and the Moon will be 80 to 85 degrees from the Sun right in the middle of the polarization band (which peaks 90 degrees from the Sun). Using polarizing filters, it will be possible to darken the sky near the Moon and Jupiter and, just maybe, make the planet visible earlier in daylight.

    Frank Reed
    Conanicut Island USA

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