Bye, Bye Venus, See You On The Other Side

A colorful 22-degree halo, the most common variety, rings the sun yesterday afternoon. Like a prism, the ice crystals spread white light out into a rainbow spectrum giving the inner edge a red-orange tint and outer edge a pale blue. Photo: Bob King

A reminder to keep an eye out for halos around the moon and sun. We’re outside more often during the warmer months with more opportunities to notice things in the sky. Yesterday I caught the bottom edge of a colorful solar halo while making that first buzz with the lawnmower through a jungle of dandelions. Halos are created when light is bent or refracted by billions of microscopic, pencil-shaped ice crystals in cirrostratus clouds. Most have a radius of 22 degrees, making them 44 degrees or “four fists” in diameter. If you see thin, wispy clouds that stretch like a veil across the sky, halos may be in the offing.

Bye, bye Venus! Watch as Venus departs the evening sky in the next two weeks. These maps show the view facing northwest about 45 minutes after sunset. Created with Stellarium

Being outside in warmer weather also makes it easy to follow Venus’ quickening exit from the evening sky. Remember when it set at midnight? No more. 45 minutes after sunset tonight, the shining planet will be only 15 degrees high (a fist and a half held at arm’s length) in the northwest. A week from now that shrinks to 10 degrees and by late May, it’ll be lost in twilight’s glow.

Venus is a thin crescent through binoculars and small telescopes.

Venus is rapidly closing in on Earth, growing larger all the time. You should now be able to see the planet as a tiny crescent moon in 10 power binoculars. Make sure to focus sharply and observe in early twilight, when the planet’s glare is reduced. Venus undergoes phases just like the moon.

When it’s on the opposite side of the sun from Earth, it looks “full”, but as the planet catches up with ours, Venus’ phase shrinks to half and finally a crescent before gliding between the Earth and sun.  If you observe Venus regularly through the end of the month, you’ll see the crescent enlarge and grow thinner as the distance between the two planets shrinks.

Venus as a "reverse" crescent on June 15

After crossing the solar disk on June 5 during a rare transit, Venus will swing west of the sun and pop out days later in the morning sky at dawn. It will still be a crescent, but because it will then be on the other side of the sun as seen from Earth, the “left” or side of the planet will be illuminated as a thin crescent. The flip-flopping crescents are fun to see in binoculars and telescope; there’s no better demonstration of how Venus keeps on truckin’ along its orbit. As for the June 5 transit, I’ll have more on how to view it soon. It will be the last time in our lives we’ll be able to see one.

As Venus orbits, its changing angle with Earth and sun lets us see it in different phases like the moon. In the evening sky, the planet is to the left or east of the sun; when visible at dawn, it's to the right or west of the sun. Illustration: Bob King.

11 Responses

  1. Jessie

    I’m sorry, i couldnt find a place to just to you on it. On friday night as my friends and i were sitting outside we seen, what most people would say a shooting star. But it was very large and greenish color and as it shooted threw the sky it left a small trail. Can you please explain and tell me what that was? We have never seen anything like it before.

    1. astrobob

      Hi Jessie,
      You saw a brilliant meteor called a fireball. Pieces broke off and burned during its supersonic flight through the atmosphere. The trail was a tube of glowing air from the fall called a “train”.

    2. Mike

      Jessie-

      Not sure if you were in Northern MN. But I saw a green fireball too on Friday around 11pm or so. It was awesome. In the eastern sky. I was in a screened porch with dim lights on and I saw it shoot off about two fists above the horizon for about 4 seconds or so. I was in mid conversation and I stopped and starred, then said a whispered, “Wow.” and went back to talking about the amazing Scotch we were tasting. No one had any idea what I saw, and I never explained. Haha, it was a great night.

  2. caralex

    Nice article, Bob. I’ll miss Venus! It seems hard to remember a time when it WASN’T high in the western sky after dark! How long has it been there, now? Five months or so, isn’t it? How long will it be before it returns to the western sky?

  3. Francis

    Hi Bob, I am in Uganda East Africa. Can anybody in this part of the world view this spectacular historic transit of Venus?

    1. astrobob

      Hi Francis,
      Yes – you’re just within the visibility zone! The transit will be in progress from your location on the morning of June 6.

  4. Meredith

    Hi Bob, I came upon your blog after seeing some unusual images in a bunch of photos I took this morning. They seem to be two planets/the moon. I really don’t know much about this but am very curious as to what is in my photos. One perfect round circle, which I assumed to be the moon is the one closer to the sun in the photos. In a few of the photos, depending on my angle, this ‘circle’ had an amazing red glow that I can’t even describe, almost looks like a funnel shape. The other ‘thing’ in the photos was just under this reddish moon (or whatever that was). This 2nd one is not as clear but is definitely a circular shape. It appears almost purplish in the photos but seems to be further away or maybe shadowed. If you could give me any idea what I’m seeing I would greatly appreciate it! As well, there was a photo I took yesterday evening of a plane in the sky & when I looked at it today, I enlarged the photo and saw this same ‘moon’. Please let me know if you would like to see the photos, anything that could help answer what is to me, a mystery. Thank you in advance
    Cheers!

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