3 Bright Planets Slow Jam At Dusk This Week

Jupiter, Venus and Mercury last night 35 minutes after sunset low in the northwestern sky. Details: 150mm lens at f/2.8, 1/30″, ISO 400. Photo: Bob King

Last night we finally cleared off after four solid days and nights of gray and rain. Sparkling low in the northwestern sky was a most welcome sight – Venus, Jupiter and Mercury. This week they will undergo to a series of remarkable gatherings in the early evening sky.

Venus leaped out immediately as the brightest of the trio. It stood 6 degrees above the horizon; that’s three fingers held horizontally at arm’s length. Jupiter jumped out next some 5 degrees to the upper left of Venus. Mercury, the dimmest of the the bunch, was very easy in binoculars but took a bit of concentration to see with the naked eye.

I’ve highlighted several nights of the triple planet gathering over the coming nights. Jupiter is colored yellow and Mercury pink to tell which is which. Created with Stellarium

This jam has just begun. Watch over the coming nights as the three planets move closer together to form a series of ever-changing jeweled triangles. Tomorrow night Mercury and Venus will be closest (1.4 degrees); Mercury and Jupiter on Memorial Day (2.3 degrees) and Venus and Jupiter on May 28 (1 degree).

All you need to see them is an unobstructed view to the west-northwest. You can begin your search about 30 minutes after sunset; get an early start because the planets set about an hour later. Binoculars can prove most helpful in case the sky’s hazy or if you have difficulty finding Mercury.

Left: If you could hover high above Earth’s north pole today and look down on the solar system, this is how the evening planets would be laid out. You can easily see how far they are from one another. At right, viewed from the flat plane of the solar system, they appear to bunch up. These occasional bunches caused by perspective are called conjunctions. Illustration: Bob King

As you can see from the nightly maps,  Mercury moves upward from the western horizon to join Venus, passes it and then teams up with Jupiter. Mercury moves rapidly because it orbits the sun most closely. Venus is also moving up from the west but more slowly, so it essentially stays in the same spot. Jupiter meanwhile drops down toward the western horizon. Earth’s motion around the sun is much faster than Jupiter’s causing the sun to literally “get in the way” between our two planets. From our perspective, Jupiter will soon disappear in the solar glare and won’t be seen again until early July when it reappears in the morning sky.

Although the trio may appear close to one another in the sky, they’re millions of miles from each other and the Earth. We see them together because they lie along the same line of sight for the coming week.

8 Responses

  1. Craig

    Thanks for posting this, I just saw this here in southern wisconsin and was wondering what they may be!

  2. Giorgio Rizzarelli

    Aha Bob so you too have low clouds 🙂 … that photo you posted seems one of my shots on sea with the almost-always present low cloud banks.. Glad you catched the trio! We’ll have four grey rainy days also here, but starting from today. But one never knows. Clear skies!

    1. astrobob

      Mostly cloudy skies and rain are also in our fore starting tonight through next Thursday! Perfect timing.

  3. caralex

    Saw the three of them low in the west at about 9.30 last night. Hard to believe just how EASY Mercury is to see – it’s really quite bright, isn’t it? Then I turned round and saw a beautiful full moon rising in the south-east. Just gorgeous!

    Bob, I read in Sky News that the rising moon and setting sun were simultaneous last night, but no explanation was given. Can you explain the significance of this? Doesn’t it happen every month, or was last night an exception?

    1. astrobob

      Hi Carol,
      Mercury’s kind of a surprise planet that way sometimes, isn’t it? As for that simultaneous moonrise-sunset, only in some places but not in most. They certainly weren’t for my town (Moonrise was at 8:28 p.m., sunset at 8:47 p.m.). It was still some hours before the moment of full moon in the Midwest so the moon would necessarily rise before sunset. The delay was less in the Pacific time zone where the moment of full moon was closer to the time of sunset. In San Francisco the moon rose 11 minutes before sunset. Better yet was Honolulu where the two were separated by only 3 minutes.

      1. caralex

        Interesting – the article didn’t actually specify where, but as it’s a Canadian mag., I thought it would refer to anywhere here. Actually, now that I think of it, our GPS flicked to night-time background (meaning sunset just happened), while the moon was already up.

  4. rose benitez

    I see them so clearly im videoing for the pass three evenings/nights. Im so amazed such a beautiful site. The one which is Jupiter I think is moving towards Venus I think it is each day it gets closer. I think they are mating. I cant see a third planet but I have this deep feeling that something else is there.

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