See Venus And Spica’s Seemingly Eternal Conjunction

Venus and Spica poke out from the treetops this morning during dawn. This photo was taken about 5:45 a.m. The two were less than 1.5° apart. Bob King

If you head outside when the dawn light just begins to swell and look low in the eastern sky you’ll immediately notice a pair of bright objects. The “big” one is Venus, and sitting on top of it is the star Spica, Virgo’s brightest. They’ve been closing in on one another for days. Normally, the a planet and star approach one another, pass and separate, but not this time. Instead, we’ll see Venus and Spica stick together at least through Nov. 18.

As Venus cycles around the sun very 225 days, it passes between the Earth and sun in inferior conjunction and on the opposite side of the sun in superior conjunction. During this time, the changing angle the planet makes with the sun causes it show phases just like the moon. At inferior conjunction, it’s closest and moves fastest. Bob King

So what’s going on? You’ll recall that Venus is fresh to the morning sky after passing between the Earth and sun on October 26. Venus is the faster planet because it orbits closer to the sun. Since it’s this side of the sun when it laps the Earth, it’s traveling fast from our perspective. We watch it speed from the evening to the morning sky and climb the eastern sky at dawn in a hurry.

They just won’t part! At closest, on the mornings of Nov. 14-15, the two will be just 1.25° apart. Stellarium

Spica’s moving, too. It slowly moves up in the morning sky, gaining a little bit of altitude each morning. Its day-to-day slog to the west is caused by Earth’s motion around the sun. Earth’s speed varies little, so Spica climbs out the east at a constant rate of about 1° per day. Venus on the other hand is rapidly moving up and away from the sun (again because it’s close to the Earth right now) fast enough to keep up with Spica. As a result, they stay close together in the sky for more than a week instead of just sliding past each other.

This affords skywatchers lots of chances to see the two shiny objects close together day after day after day. The best viewing time is between an hour and a half to an hour before sunrise when they’re both visible in a semi-darkened sky. For me that’s around 5:30-6 a.m. local time. If you have 10x binoculars or a small telescope, they’ll reveal that Venus is a skinny crescent. Look low in the east and start your day with beauty.

10 Responses

  1. Edward M. Boll

    Turning to Comet 38, now about magnitude 9 and a half and located near the twins of Gemini I could not for sure make it out. I then turned toward V1 hoping to use Venus as my guide but the planet had not risen yet. Maybe I will retry for V1 in a few more days. It is brightening rapidly some putting it at mag 7 and a half. If things work out as predicted it should break mag 6 by Thanksgiving.

    1. astrobob

      Hi Edward,

      I think some of those estimates are way high. I just saw it Tuesday morning, and I estimated mag. 9 — very little change from my previous estimate.

  2. Edward M. Boll

    Speaking of comets, Wirtanen which is reported now around magnitude 6 and a half, probably about 4 in mid December should not only be an easy binocular comet even those not familiar with stars should be able to locate it on December 17 as I read that it will be within 2 degrees of the Pleiades. Anybody should be able to recognize that cluster.

  3. Hi Bob, any forecast out there for the Leonids meteor shower? and should the next Leonids “storm” be expected in 2032 (after the ones in 1933 and 1966 intervals) or in 2034 (for 33 years after the actual 2001 one) ?

    1. astrobob

      Hi BC,

      This won’t be a good year for the Leonids (Nov. 17-18) though skies should be moon-free before dawn. I’ve heard that we won’t be getting a great shower in 2032 as we did in the early 2000s. Will have to wait for another round.

      1. Another round? That means 2064… good thing I saw the storm in 2001. Oh well, my plan was to be around when comet Halley comes back in 2061, maybe i can make it to the next meteor storm in 2064 at age 103!

        1. astrobob

          BC, that gets me thinking now. I’ll be 107 when Halley comes by again. I’m afraid my stressed lifestyle precludes seeing it a second time. Glad I showed up for one round!

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