If You Can Find Mars, You Can Spot Ceres And Vesta Too – Try It!

Ceres, the largest asteroid, and Vesta, the brightest, lurk near the bright planet Mars this spring. They’re easy to see in binoculars and showed up clearly in this 30-second time exposure made April 20, 2014. Credit: Bob King

Who hasn’t been dazzled by the Red Planet these April nights? Come 10 o’clock, Mars shines brilliantly in the south accompanied by the the blue-white star Spica. But did you know that just a short distance away, asteroids Ceres and Vesta are making their rounds in the night sky too?

Use this map to get started. The star to find is labeled Zeta Virginis, located a little less than one outstretched fist to the left of Mars. Point your binoculars there and then use the more detailed map below to navigate to Ceres and Vesta. Stellarium

Ordinary binoculars will easily show both. Last night I stood in my driveway with a pair of 8x40s and hopped from Mars to Zeta Virginis and then to the “Vesta Triangle” and saw them in the same field of view. Vesta shines at magnitude 5.8, bright enough to be dimly visible with the naked eye from a dark sky. Talk about easy. I hardly had to try with binoculars.

Ceres and Vesta hang out this month  near the “Vesta Triangle”, a small group of stars located about 3 degrees north of Zeta. Positions for both asteroids are shown for 10 p.m. CDT every five days with stars to magnitude ~8.5. The stars will remain in their places, but you’ll see Ceres and Vesta move slowly among them as the nights pass. Click to enlarge, then print to use outside. Created with Chris Marriott’s SkyMap software

Ceres, at magnitude 7, is fainter but well within easy reach from suburban skies. Now the cool part – both asteroids will be no more than a few degrees apart through July. That means they fit in the same binocular field of view, so if you find brighter Vesta, Ceres will always be nearby. Matter of fact, they’ll really get close come late June and early July. As we approach that time, I’ll provide additional maps.

Vesta (left) and Ceres. Vesta was photographed up close by the Dawn spacecraft from July 2011-Sept. 2012, while the best views we have to date of Ceres come from the Hubble Space Telescope. The bright white spot is still a mystery. Credit: NASA

If you’ve never seen an asteroid before except in close up photos taken by spacecraft, lower your expectations right now. They look exactly like stars. Even Ceres, the largest at 590 miles in diameter, is too small to appear more than stellar in even a large telescope. Vesta’s smaller yet – 330 miles wide – but brighter because it’s somewhat closer and also more reflective.

That’s OK. Getting to see the real thing is what skywatching’s about. I love the photos but honestly get more of a kick out of seeing the asteroids with my own eyes. When life gets tedious, I like to think of them silently cycling over my little patch of earth, Vesta 114 million miles away, Ceres 153 million.

Dawn’s Greatest Hits at Vesta – A Look at What We Learned (spiced up with guitar)

Coincidentally, both Vesta and Ceres, which orbit in the main asteroid belt, are the targets of NASA’s Dawn Mission. Dawn visited and studied Vesta from July 2011 to Sept. 2012 and revealed that the tiny world had something much in common with its big brothers, the planets. Vesta was once hot enough to melt and differentiate into an iron core, rocky mantle and crust like the terrestrial planets. Heat from the decay of radioactive elements like aluminum-26 caused heavier iron to trickle down to the core while lighter minerals floated to the top to form Vesta’s crust.

Ceres rotates once on its axis every 9 hours (Vesta takes 5.3 hours). These four photos span 2 hours 20 minutes. Photos taken with the Hubble Space Telescope. Credit: NASA/ESA

While Ceres can still be considered an asteroid it’s also a member of a select group of dwarf planets, bodies large enough to have crunched themselves into spheres through their own gravity but not big enough to clear the region they orbit of smaller asteroids. Dawn’s on its way to its final target, a rendezvous with Ceres next February. Unlike dry and rocky Vesta, Ceres shows signs of water and clay.

While you’re waiting for the next close up photos, why not go out on the next clear night and see them for yourself?

11 Responses

  1. Jon Dannehy

    I remember looking at Vesta a few years back and it looked distinctly yellowish to me. This was through my 12.5″ scope.

    1. astrobob

      Hi Jon,
      You know, that was also my impression the last time I looked at it through a telescope. I’ve only seen it in binoculars this season but tonight I’ll be using the scope when the class goes out for observing. Isn’t this great weather again to finally be out?

    2. Troy

      I noticed the same thing. It is very similar to the color of Mars. I do have a bone to pick with the DAWN team, where are the color images?

    1. astrobob

      Hi Josh,
      It could be the time of year for stars – lots of bright ones left from winter concentrated in the western half of the sky along with Jupiter. Then in the south you’ve got bright Mars and Saturn, so yes, there’s a nice bunch of planets that give the sky a little extra sparkle this spring.

  2. Richard Keen

    Bob, that’s a real nice map of Ceres and Vesta. It’s very tantalizing at the bottom where both asteroids are still closing in on each other in early July. Do you know when and how close their nearest approach to each other will be? Looks like they’ll both fit in the field of a 12-inch scope!

  3. Dynamite (D.George)

    I have a pair of moderate Binoculars of home and I saw both Ceres and Vesta and I was intrigued. Thanks for the heads up I shall be looking at these two interesting bodies. Thankfully July 10 is a Thursday this year so I have nothing booked unless I travel to a non lit area of Britain again like last time to see Scorpio.

    1. astrobob

      Hi D. George,
      Thanks for sharing your observation. I hope you get to see them at their closest.

  4. Lisa Rodgers

    Hi Bob,

    Great website. I truly enjoy reading it. I was wondering if you could explain something to me. I use Stellarium to see what out there in my nights sky. I always use TimePassages Astrology software and I am noticing a discrepentice between the 2 software. My specific issue is the location of the planets. Astrologers around the world say Mars is in Libra, Stellarium to me looks like Mars is in Virgo. Am I missing something is astrology way off the mark.

    1. astrobob

      Hi Lisa,
      Thanks! Stellarium is showing the correct planet positions. Mars is indeed in Virgo. Astrology is off the mark by a couple thousand years. If the Earth’s axis didn’t precess (a slow wobble with a period of about 26,000 years) Mars would be in Libra. But because of precession, Mars, the sun and all the rest have moved westward along the zodiac over the millenia. Astrology sticks to their ancient positions and ignores the current – and ever-changing – reality.

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