How To See Pallas, Spring’s Brightest Asteroid

Up early tomorrow? Find a spot with a wide open view to the southeast and look for Venus and the crescent moon in twilight. Stellarium

The sky has been deceptively quiet of late, but things are brewing. Tomorrow morning a thin crescent moon parks just shy of a fist to the right of the planet Venus. The best time to see the pair will be around 40 minutes before sunup low in the southeastern sky.

During the evening hours you can watch the bright asteroid Pallas ply the heavens with nothing more than a small telescope or pair of 50mm binoculars. 2 Pallas, the second asteroid discovered after Ceres, was found by German astronomer Heinrich Olbers on March 28, 1802. As far as asteroids go, it’s big — at 318 miles (512 km) across, Pallas ranks as third largest. It orbits in the main belt between Mars and Jupiter and makes one orbit of the sun every 4.6 years.

The European Southern Observatory’s (ESO) Very Large Telescope took this photo of Pallas, revealing what appears to be a cratered surface and an intriguing bright spot reminiscent of the bright spot on Ceres. Pallas is a dark asteroid related to carbonaceous meteorites.
ESO / Vernazza et all.

Just like a planet, it’s closest to Earth and brightest at opposition, when asteroid, Earth and sun line up in that order. That happens on April 6, making the entire month ideal for following its track among the stars. Pallas shines at magnitude 7.9 which puts it within binocular range for suburban and rural skywatchers. If light pollution brightens your sky then you’ll need a small telescope. And I do mean small. Even a spotting scope will pop it into view.

Pallas and all the other asteroids look exactly like stars because they’re all too small to show a disk like the planets do. That’s why astronomers settled on the name asteroid in the first place, after the Greek “aster” and “oides” for star-like. Other names considered but rejected included planetkinplaneretplanetling or even stellula. I’m kind of sweet on planetkin but that train left the station long ago. Originally, Pallas and friends were called planets, but so many were discovered, and they were all tiny and occupied the same zone between Mars and Jupiter, astronomers came to realize they were in a category all their own.

Arcturus comes up in the northeastern sky below the handle of the Dipper. It’s the brightest star in Boötes the Herdsman. I’ve also labeled the 2nd magnitude star Muphrid (Eta Boötis) which will also help in finding and tracking the asteroid Pallas (see below). Stellarium

To find Pallas you only need to find Arcturus. It’s that unmistakably bright, twinkling orange star that glimmers low in the northeastern sky below the handle of the Big Dipper. If you have a clear view east you can see it as early as 8:30 p.m. but better to wait till around 10 o’clock when it climbs to a convenient height.

This map shows the position of Pallas each night (tick marks) with dates labels every two nights to avoid clutter. Stars are shown to magnitude 8.5. North is at top on the map. If you’re viewing Pallas early in the evening, tip the map to the left so it matches the orientation of Arcturus and Muphrid in the sky. Right-click on the map, save and make a print out. If you’d prefer a black-sky background in your maps, click hereChris Marriott’s SkyMap software with additions by the author

The fun part of Pallas-watching is first in finding the asteroid (congratulations in advance!) and then watching it slowly move night to night against the background of the distant stars. Some observers like to sketch the star field on paper and then plot the asteroid’s position on clear nights. Right now, Pallas shines just about 5° southwest of Arcturus and will remain within 5° of the star through the 11th. Why is 5 a happy number? Because that’s about the field of view of a typical pair of binoculars. So if you can find Arcturus, Pallas will be close by.

Pallas has a steeply inclined orbit compared to many asteroids. Positions of the planets and Pallas are shown for April 5, 2018, the date of opposition. JPL Horizons with additions by the author

The map shows the position of Pallas each night around 10 p.m. Central Time. It moves only a very small distance in several hours time, so the positions shown will work for all time zones across the continental U.S., Canada, Central and South America. For other locations just interpolate between the dates. On the evening of the 10th, the asteroid passes very close to Muphrid — too close for binoculars but a telescope will show it, and if you’re patient, you can watch it move in relation to the star in just an hour or two.

We may learn much more about Pallas soon plus get a bounty of close-up photos. NASA is considering funding a small satellite called Athena  that would piggyback on the Psyche Mission to the metal-rich asteroid 16 Psyche. After launching in August 2022, the two spacecraft would part ways, with Athena getting a gravity assist from Mars to fling it onward to Pallas for a 2024 flyby.

You needn’t wait till 2024 to get to know Pallas. Just poke your head out the next clear night.

30 Responses

  1. There’s a multiple (two moons’ shadows at once) shadow transit on Jupiter tomorrow morning. Has anyone seen shadow transits in daytime?
    I’m thinking of calling it the “April Fools’! See Two Black Holes on Jupiter” event.
    07:53EDT to 09:00EDT.

    1. astrobob

      Thanks for calling attention to the transits. I think the first one of Europa will be hard but not impossible to see in the daytime sky, but the second one of Ganymede should be easy in daylight.

  2. Thanks for the Pallas article, Bob. It’s nice you had already talked about Arcturus recently. Poor Muphrid is probably seldom in the limelight w/ it’s flashy neighbor. I doubt I can see Pallas here in the bright Philly suburbs. The progressive naming conventions for asteroids is reminiscient of the Trans-Neptunian objects … I suggest plutoid for spherical TNO’s.

    1. astrobob

      Hi Jason,
      You’re welcome. Pity you can’t see something that should be easy. Do you mostly observe planets and the moon then?

      1. Yep. Most of my star gazing takes place while walking my dog Trixie. Tonight, for instance, I can only make out Polaris & the end stars in the bowl of the Little Dipper. When I visit family in Western PA, tho, the sky is mine. I am grateful for what I can see, tho. Many of my cousins have RP & I doubt they can see the stars at all.

        1. astrobob

          Jason,
          That reminds me of going for evening walks with my dog Sammy. She’s gone now but I those were good times, and I always got out to see the sky cloudy or clear.

          1. kevan hubbard

            I had a dog once called ‘the pup'(from when she was a puppy but the name stuck)and she would stare up at the sky as I was stargazing I’m going to guess,from a humancentric angle to see what I was looking at rather than awe of the night sky….?off subject slightly and your article in ‘sky and telescope’ about seeing DSO’s naked eye.over in rival,well really one complements the other?, magazine ‘astronomy’ Bob Berman is saying that the averted naked eye can just resolve m44 into individual stars. I will have to try next time I’m in a very dark place and it’s clear and Cancer in skies.

          2. astrobob

            Berman’s awesome. I’ve seen granulation at best but then my eyes are older. Someone in their 20s or 30s under Texas or Nebraska skies might be able.

  3. kevan hubbard

    Thanks for the nice map of Pallas movements. I have,in the past,seen ceres and Vesta so it’d be nice to add Pallas but it’s a fair bit dimmer than the other two. I can’t remember now but one was just naked eye about Uranus’s magnitude (Ceres?)and the other just under naked eye visibility (Vesta?). Pallas however would seem to be at the Neptune range of magnitude perhaps a bit brighter.forcast for cloud until Friday anyhow although I did see the ISS cross the sky last night.on the daylight saving time front I note that of 2021 the European Union has said that it will remove daylight saving time and keep the same time all year.of course their member states will still be in 3 time zones unlike China which has one time zone across such a vast nation.one time zone is okay if you are a vast thin long north south nation like Chile but for a wide(and long one)like china it creates problems.

    1. astrobob

      Kevan,
      Yes, Pallas about equals Neptune but can get almost as bright as Uranus. Vesta’s the brightest, right at naked eye or bit brighter. Didn’t know the EU was eliminating DST. There’s talk in California of changing DST but not where I live.

  4. kevan hubbard

    I don’t know how old Bob Berman is maybe late 50s based on his photo and he lives in northern New York state,or did.he doesn’t say how old he was or where on the planet he was when he resolved m44 naked eye. I even find m45 a challenge to resolve naked eye just a big misty patch to me!

    1. astrobob

      I met Bob at Alcon 2018 in Minneapolis. A fine gentleman with a lovely wry sense of humor. I wish we could have talked more. He was moderator for a panel discussion I was part of. I’d say he was about 60.

      1. kevan hubbard

        He ran his own observatory called either the lookout or over look observatory.if I recall the nearest town was Woodstock which is about halfway up NY state but I will have to check as apart from NYC and Buffalo my geographic knowledge of NY State is rather poor.had I been a hippy circa 1968 it’d help me know the exact location of Woodstock!

  5. Brad Hala

    Bob: we were watching the ISS cross the sky last night and saw a second craft keeping pace with it about 8 to 10 degrees south of ISS. Thought maybe a Soyuz but I see there is one launching tomorrow. Any ideas about what we saw? (this was @ 8:45 p.m. Tues. night from s.e. Saskatchewan)

      1. Brad Hala

        We didn’t spot the second light til ISS was well past Capella. From there to Denebola the second light did appear to keep pace and distance from ISS. The ISS at peak was forecast as -3.8 and this second light was possibly a 1.0 ?

        1. astrobob

          Brad,
          As far as I can tell nothing is in orbit near the station. Normally, if a spacecraft is approaching the station it follows the same track. Give me your latitude and longitude and I’ll see what it might have been. I’m thinking an unrelated satellite, but we’ll see. Thanks.

          1. Brad Hala

            Bob: I checked the Brighter Sats. page on Heavens-Above and saw nothing even remotely close. As I said- from Capella to Denebola it seemed to maintain distance from(8 or 10 degrees) and speed with the ISS. In case you come across something, my location is 49.66 N., 103.85 W. Thanks

          2. astrobob

            Thanks, Brad. I was going to check it but you already have. It’s certainly an interesting sighting. If they were parallel and traveling the same speed it would imply the same altitude orbit. I may ask some other people what they think.

          3. kevan hubbard

            I saw the ISS cross the skies from my location of Seaton Carew in North east, England (54.6608nth./1.1935w.)last Sunday it was crossing n.w.to s.e.and went over about 2130hrs.. I wonder if you saw the Hubble? lot’s of other things are flying around up there some secret and some not. l’ve seen a few funny things up there over the years but only 2 that I can’t explain not to say that they can’t be explained .the most recent was Good Friday last year.about 4 lights heading south to north not too unusual but one was weaving in and out of the others rulling out satellites. I pretty sure it wasn’t birds or bats or insects.unlikely to be planes or drones doing areobatics at 0100!

          4. astrobob

            I’ll let Brad chime in, but the Hubble isn’t visible from that far north. Sadly, not from my latitude either.

  6. Troy

    First time I’ve seen that image of Pallas from the VLT. The detail is quite remarkable. White spots on yet another body in the asteroid belt?

  7. kevan hubbard

    Interesting answer…. space junk. I once saw something go off above me that lit up the ground like daylight but it produced no noise suggesting it was very high up.l assumed that it was a bolide but it could have been space junk burning up?will we be seeing any flashes from the satellite that India recently destroyed with a missile I wonder?it wasn’t that high up I think that the report I read 181km above the surface?

    1. astrobob

      You saw a flare from an Iridium satellite, Kevan. About the India satellite — probably not because the pieces are pretty small but you never know.

  8. kevan hubbard

    Spotted Pallas!night of the 10th at about 2245 to 2230. I tried in my 8×25 monocular and think it might be just visible but uncertain in such a small objective so I brought out my Russian 20×60 binoculars,a classic with ‘made in the USSR ‘on them!,they brought it out no problem.60mm is the baby end of ‘big binoculars’but believe me that holding 20×60 still for long is not easy and I don’t have a mount for them.best with this power sit in a deck chair and let your head take the weight…. better still a mount! I think that they began to resolve m3 too which I took a peak at.a rather cold April so I didn’t stay out too long.

      1. kevan hubbard

        I bought these when Constantine chenyenko (excuse my probably wrong spelling of said gentlemans name!)was head of the supreme Soviet!they are of a semi sealed construction with the panels being sealed with the black covering that binoculars have on them the only weak spot might be the eye pieces as the instrument is not nitrogen purged. I have thought about a tripod but there still remains the problem of looking at the canopy which you get with any non star diagonal telescope.a firm called opticron does a pair of 30x70s which I should guess are impossible to hold still?my 20×60 can be held still believe it or not but not for long they gave amazing views of the Moon and began resolving m3.m3 goes from being a fuzzy ball in my 8×25 monocular to a granular ball in the 20×60. I note that there’s another astroid about now, Iris ,but it is over the 10th magnitude.ceres too but it’s very low in Scorpius.

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