Get High On Venus

Venus shines at dusk in the western sky more than an hour after sunset this past weekend. I had to put up with power lines like most of us do when shooting photos near the horizon. Bob King

Man, Venus is high at dusk. I was driving home over the weekend expecting to see it near the horizon. Instead it stood a fist high in the western sky an hour after sundown. And bright, too! Venus has moved from challenging to easy. With its altitude gain, the planet isn’t as compromised by twilight as it was a few weeks ago.

If you haven’t gone out to greet the goddess, April’s a great time to do it. Venus remains moderately high in the western-northwestern sky throughout spring. As it slowly climbs away from the sun, the winter stars, now in the western sky and sinking a degree a day, meet and pass the shiny planet. The most anticipated meeting will be with the Pleiades in late April. On the 22nd the two will be only 3.5° apart and make a fantastic sight with or without optical aid.

This simulation shows a wide swath of sky from southwest to northwest. All the winter stars are now sinking toward the western horizon. Some of the famous ones, like the Pleiades, will meet up with Venus later this month and next. Stellarium

As an inner planet, Venus has phases just like the moon. When it’s on the opposite side of the sun from Earth it looks like a little full moon. When off to to the side of the sun, we see it half-illuminated like the first quarter moon. And when Venus passes between the Earth and sun, it goes from a waning crescent to waxing.

Venus orbits the sun every 224 days. From our perspective, it changes phase from full to half to crescent (left side of diagram) , then goes through the same sequence in reverse. Right now, it’s in gibbous phase not far to the left of the superior conjunction point. Just before and after inferior conjunction, which occurs on October 26, the planet is a very thin crescent. Since it’s also closest to the Earth then, it’s big enough to see its shape in binoculars.

This evening, the planet is 94 percent lit which makes very much gibbous, almost full. But in the weeks and months to come, as it swings round the sun, moving faster that the Earth, it will wane to half and finally a hair-thin crescent before it departs the evening sky. A small telescope will easily show all of Venus’ phases, and when it’s a crescent, binoculars are even up to the task.

Venus is so bright, it’s always the first “star” to appear at dusk. It will be your friend every clear evening.

5 Responses

  1. caralex

    I can easily see it now from my kitchen window, without going outside! I saw Mercury too a week or two ago.

  2. Venus was an important part of the Maya calendar. I have tried to interest some Maya scholars
    to see if transits of Venus were every noted by the Maya. So far, none have taken up my invitation.TOV’s which occur at dawn and dusk are naked eye visible, as well as through
    the right thickness of clouds.

    1. astrobob

      Hi Herman,

      A great question. I’m surprised at the lack of interest. Certainly the Maya would have seen Venus getting closer and closer to the sun and check out of curiosity to see if it crossed the disk. More likely though (since they didn’t know it was orbiting the sun), someone would have accidentally spotted a transit. I’m guessing it would have been a big leap for the Maya to assume that a dark spot was Venus. Are there any Mayan sunspot observations? Those would occur with much greater frequency.

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