Mercury Ascends As Venus Departs And Lo, The Twain Shall Meet

Watch Venus tumble and Mercury’s fortunes rise. This panel shows the planets’ positions and the altitude of Venus on May 17, 21 and 24. The two planets are in conjunction just 1° apart on the 21st. Stellarium

Venus is plummeting. In two weeks you can kiss it goodbye from the evening sky. Happily, it won’t slink out of view as it has on some occasions. No, no. The brightest of planets will leave with a flourish in a farewell conjunction with the planet Mercury on Thursday, May 21. You can watch Venus sink lower in the northwestern sky with nothing more than your eyes, though I encourage you to bring binoculars so you can magnify it into a miniature crescent “moon”. On Sunday, May 17 it’s about a fist and a half high (14°) 40 minutes after sunset but only half that a week later. Meanwhile, Mercury’s altitude climbs from 6° tonight to around 10° on the 21st.

Venus reflects on the calm surface of a lake north of Duluth, Minn. during evening twilight on May 15. Bob King

Venus is by far the brighter with a magnitude around –4.3, but Mercury’s bright for Mercury with a magnitude of –1, brighter than any star currently visible in the night sky from mid-northern latitudes. Keep in mind however that because it’s located squarely in the twilight glow the planet won’t look as bright as it otherwise would in a dark sky. The crescent moon joins the duo to make a trio on May 24. What a great way for the two to go out with a bang!

Two planets? Yes. After Venus departs Mercury will follow in early June. Quick-moving Mercury reaches its greatest apparent distance from the sun on June 4 just a day after Venus is in conjunction with the same, then drops out of view about a week later. No one likes losing planets but in a delightful balancing act, the two small, inner planets will soon be replaced Jupiter and Saturn, the two biggest outer planets.

The northern half of the summer Milky Way rises in the eastern sky around midnight in mid-May. Stay up late and watch it from a dark sky. The spring appearance of this starry sash will make you shiver in your shoes for wonder. The prominent, oval-shaped Cygnus Star Cloud is seen to the left of center. The Scutum Star Cloud rises in the trees at lower right. Details: 20mm lens at f/2.8, ISO 6400, 25 seconds. Bob King

That duo currently rises around 1:30 in the morning in the southeastern sky. By the time Mercury and Venus depart they’ll be visible around 12:30 a.m. That’s still late but if you’re patient they’ll rise earlier and earlier and before you know it become part of the summer night-sky furniture. The rising of Jupiter and Saturn also signals the appearance of the summertime Milky Way. You can get a taste now (photo above). We’ll dig deeper into the topic in a future blog.

6 Responses

  1. BCstargazer

    Thank you Bob
    Great week coming for ISS multiple passes every evenings with spherical earth rotating from visible pass to the next one

  2. Edward M Boll

    Looking forward to the Conjunction Thurs. Friday morn conj. of Swan and Atlas will for me probably be a no show. Nice sightings this AM, of the 3 planets but I sure did have difficulty spotting Swan now reportedly dimmer than 6. It might be almost easier now to spot Y1, very well placed surprisingly still about mag 9.

    1. astrobob

      Hi Edward,
      I tried this morning but was frustrated by clouds. The best comet right now by a good margin is T2 PanSTARRS. It’s the only one that’s held “steady” and followed predictions throughout its apparition. It’s also close to mag. 8.

  3. Edward M Boll

    I just saw a an observation report making me believe that Y4 may have flared back up bright back to magnitude 8.

    1. astrobob

      That would be great. Hope so. But I suspect the 8.2 magnitude report is from J.J. Gonzalez. If so I would take it with a grain of salt. He’s a wonderful observer and more than once his observations have alerted me to potentially visible comets, but I’ve found over the years that his magnitude estimates are roughly a magnitude brighter than what I’m seeing.

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