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    Venus in daylight
    From: Frank Reed
    Date: 2020 Mar 27, 15:19 -0700

    Yes, Venus in daylight is easy right now, even without optical aid --if you know a few tricks.

    Trick 1: Use an app or do some paper calcs to get the altitude and azimuth of Venus, and for today and tomorrow also the Moon. Less than an hour ago, I was in my backyard, and skies were clear but by no means perfect. I checked my own app and found that I should expect to see Venus on azimuth 225°, which of course is exactly southeast, and 65° high. The Sun at this time was around 22° high so I positioned myself with some trees blocking the Sun and looked on the right azimuth (relatively easy to judge) and tilted my head up to the right altitude (not so easy to judge). And what do I see? The perfect crescent of the planet Venus exactly where it's supposed to be! No wait. That's the Moon. But this leads us to the next trick...

    Trick 2: If possible, determine altitude by differencing off a known body or a known structural detail in a foreground object. In thiis case I was able to check the position of the Moon. It was on the same azimuth within a degree and about 12° lower in altitude. When I looked for Venus originally, I felt reasonably confident that I was looking at an altiitude nearly 65° high, but I was too low. This is normal, in my experience. When you want to find an object in the sky, and it's above about 30°, it's almost always higher than you expect. An altitude of 45° feels like 55°. An altitude of 60° feels like 75°. Once I knew that Venus was around 12° higher than the Moon, I knew I could easiily judge that angle since I had a "paper sextant" in my pocket (don't leave home without it). That's a common US index card, 3x5 inches, in size, and when held at arm's length (25 inches to be exact) the long side subtends an angle of 11.5°. So I hold up the card with one corner at the Moon... And there's Venus right at the top of the card! It works: a bright, white dot plain as day.

    Trick 3: Walk it to a foreground tree limb or the roofline of a building. Once you have found Venus, it is very easy to lose it again. Our eyes are designed to prevent saturation by bouncing around (visual saccades), and this makes it quite difficult to stay focused on a small bright spot on a bright background. To work around this property of vision, it's helpful to locate Venus in the sky when it is sitting right on the end of a branch in a tree. When you have found it once, you can walk slowly,  keeping Venus continually in view, effectively "carrying" the planet across the sky, to a spot where Venus is hanging right off the end of a branch. Then it's safe to look away because you can return to this same spot over and over again (so long as it's within 5 or 10 minutes). You can also now show Venus to your friends... "stand right here... see that little branch? look right off end of that branch..." yields "oh my gosh!! I see it! That's Venus?!" And now you're a wizard.

    It should be possible to see Venus in daylight when skies are clear for several weeks and at any time of day. After you have found it once, you can easily adjust from one day to the next and for different times of day. The Moon will be nicely placed for the next 30 hours or so to help locate it. Also you can expect lots of "oohs" and "aahs" about the Moon and Venus together in twilight tonight and tomorrow. Time for a social media post: "That brilliant star, right by the Moon? That's the planet Venus, and it's about 400x further away than the Moon. And that dusky glow that lets us see the whole Moon inside the arms of the crecent? That's earthshine" (you can explain earthshine or not...).

    Frank Reed

       
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