Q and BA Episode 7: By Any Other Name

By Phil Plait | March 18, 2007 7:46 am

Due to my travel schedule, I am posting this one early. I hope no one minds.

Astronomical objects have a bewildering array of names. Is it M1, or The Crab Nebula, or NGC 1952, or what? Why are there so many weird names for these things?

Find out in this week’s episode of Q & BA: By Any Other Name.

Viewing options:

Watch it right here, right now!

Watch it on YouTube.

Watch it on Google video.

Download it directly from LibSyn.

Download the audio only version from LibSyn.

NOTE: If you are already a subscriber through iTunes, you may be getting both the video and the audio-only versions in your feed. This is because both versions were in one feed until last week. If you want to get only one or want to download both separately, then unsubscribe first and then click on the link(s) below.

Subscribe to AUDIO ONLY VERSION via iTunes.

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Show notes

The Question:

The question was sent in by Teri Bootelaydi:

What is the rational behind the naming and numbering of astornomical objects?!?!

I have shelves full of astronomy books and magazines, and close to a thousand sites and ‘papers’ in my Bookmarks — and not one — NOT A SINGLE ONE — explains the logic behind these labels. It’s a nightmare for an amateur to learn.

It’s as if the IAU gets together behind closed doors and laughs at us.

Images and Links

The image of Charles Messier is from the French version of Wikipedia.

The Comet SWAN picture is from makelessnoise’s Flickr collection (usage is under the Creative Commons license). That’s a meteor streak next to it! Pretty cool shot.

The Orion Nebula image is from Space Ritual’s Flickr collection (again, Creative Commons).

The image of Sirius is from Hubble.

All the myriad names for Sirius are from SIMBAD, an astronomical database.

The Crab Nebula is from the Subaru Telescope.


Comments (39)

  1. CACTUSJACKmankin

    Hahaha… Us biologists laugh at you astronomers, we have a standardized method of naming that is independant of regionality or specific field. A molecular biological study of the Pan troglodytes (common chimpanzee) will use that same name as a behavioral study even if these studies are performed in other countries using other languages.

  2. DrFlimmer

    Phil, it doesn’t matter if you post this earlier. If you post it earlier, we can watch it earlier, right? ūüėČ

    Well, that’s really strange that there are so many names for only one thing and only with the name of a not-so-well-knwon object you will not be able to find it when you do not have the coordinates even if you know all the names.

    But, the download of the LibSyn-Site is not possible by now. Maybe you are so kind to fix it, please!

  3. Max Fagin

    Well, I know there’s a Rosette Nebula somewhere in Monocerous, but I’ve never been able to find it.

  4. Lauren

    I tried clicking on the iTunes video only, and I still get both versions. Clicking on the audio only does give the audio only ones.

    I started laughing as you read off all those names for Sirius. It sounds like it would be a lot easier to just scrap all of those naming systems and have just one for everyone to use. However, I know that it reality that’s a lot more complicated.

  5. ABR

    CACTUSJACKmankin…my thoughts exactly!

    Linnaeus! Binomial nomenclature! International Code of Zoological Nomenclature! (and ICBN, too!) Biologists rule!

    But shhh! let’s not mention Phylocode, okay?

  6. Irishman

    Rose nebula N11A

    NGC6720 Rose Nebula

    The “Rose Nebula” (NGC 2237) (the Rosetta Nebula)

    And, for a different take, an article about the Cat’s Eye Nebula, and why it “should” be called the Rose nebula. (Note: religious themes.)
    Note to Phil: google “Rose nebula” and a bunch of links show up on this topic.

  7. spokelig

    And better not mention the different names for more or less the same gene in all the organisms sequenced so far… guess every branch of science has its homebrewed nomenclature somewhere.
    Somehow, one seems to get used to it. But it does make you wonder how much exactly you don’t know about your object (star, gene) of interest, just because you don’t know all the “aka”s for it.

  8. OptimusShr

    Astronomers need a better cataloging system.

  9. DasJan

    Amazing. But your pronunciation of “Bonner Durchmusterung” is aweful! :)

  10. My mind instantly flashed to “NGC 5128” a very strange looking radio galaxy.

    It is probably known by other names or numbers.

    All of this reminds me of personal contact numbers and words:

    * Home phone #
    * Cell phone #
    * Street Address
    * Zip Code
    * Area Code
    * email
    * Web Site

    The social security number remains consistent, therefore:

    We need Stellar Security Numbers

  11. Excuse me please, but I could not resist pasting this quick follow up comment:

    The most spectacular original discovery of Dunlop is perhaps that of peculiar radio galaxy NGC 5128 in Centaurus (also called Centaurus A), his Dunlop 482. Also included in his original discoveries are Sculptor Group galaxies NGC 55 (Dun 507), 300 (Dun 530), and 7793 (Dun 608), and a considerable number of further southern galaxies, open and globular clusters, diffuse nebulae, and 4 planetary nebulae (NGC 2818=Dun 564, NGC 5189=Dun 252, NGC 5882=Dun 447, and NGC 6563=Dun 606). Dunlop has included 7 Messier objects in his list: M6=Dun 612, M54=Dun 624, M55=Dun 620, M62=Dun 627, M69=Dun 613, M70=Dun 614, and M83=Dun 628.

  12. ABR

    “We need Stellar Security Numbers”

    Yeah, biology has those, too. At least, the Integrated Taxonomic Information System (ITIS) has assigned a Taxonomic Serial Number (TSN) for each species (plant, animal, fungi and microbes) from North America (and beyond). Codes like this are handy for computers, but not for conversation even amongst experts.

    Another thought would be bar codes. Those have been in increasing use in insect collections to help track specimens, collection data, etc. Perhaps spectragraph plus position for astronomical objects? For all I know, though, one of the naming systems brought up in this Q&BA is just such a thing.

  13. John Parejko

    Phil: PPM stands for “Position and Proper Motion,” sort of a precursor to Hipparcos, done from photographic plates.


    I only know this because it used to be the only field star catalog my computer had space for, when I was first using XEphem.

  14. John Parejko

    Oh, about people’s suggestions for universal catalog names: most new telescopes have standardized to something like:


    where RA is the right ascension–essentially longitude–expressed in hours, minutes and seconds, and Dec is the declination–essentially latitude–expressed in degrees, minutes and seconds. But some catalogs list them both in decimal degrees… And that brings up another issue: sexigesimal vs. decimal for positions! Ahhhhhh!

    But we still need to have different names for objects observed in different wavelengths, because an X-ray source that appears near a galaxy on the sky might not actually be associated with that galaxy at all! So, if we called both the optical and X-ray images the same name (because they were in the same position in the sky), we might actually be incorrect. And determining whether two sources in different wavelengths actually correspond to the same object is not easy… It’s related to what I’m doing my thesis on, so this Q&BA is near and dear (or perhaps not so dear) to my heart.

  15. Well, with astronomy the challenge is probably the inability to categorize objects consistently. With biology, we could probably set up a statistical rubric for DNA or Biochemical composition for classification. Life is rarely amorphous, it has to fit a set of criteria just to function as a living thing. The only requirement for something to be astronomical is that it just has to be in space (i.e. really really high, Tom Leary probably counted for God’s sake!) So EVERYTHING gets classified, and unfortunately, EVERYTHING moves. Take the Tunguska NEO, we’re not sure whether it was an asteroid or a comet, though the “History” Channel is sure it was a Russian Roswell.

    My point is that if we create a singular unified classification system, we’re going to encounter something that won’t fit. Could you imagine if we could somehow use a magical tooth fairy to detect dark matter and it flows in streams like water and does have an unforeseen effect on the universe (It may as well, since we don’t really know that much), then we’ll need to map that too, and either change the system, or create yet another system. Ta-Da! We’re back to square one.

  16. It strikes me that this conflagration of designations may make initial discussions harder but might actually help Astronomy as a study. Since most objects in the sky don’t have conversational names like “Crab Nebula,” “Horse Head Nebula” or “Andromeda Galaxy” the myriad numbering systems could prevent researchers from making assumptions about the object before reading findings and conclusions about that object. We do all make certain assumptions based on our familiarity with wording. Much of the hullaballo about Pluto stems from the number of people, astronomer and layperson alike, that were just used to thinking of it as a planet all this time.

  17. OK, for some reason the LibSyn posts didn’t go live. I just fixed that, so they should be good.

    I don’t know why iTunes is still showing one feed. I think this may be because iTunes sucks, since most problems I have with it are due to that. However, I can’t rule out some mistake I made. I’ll look into it when I can.

    And just a note: I know what PPM stands for. Sometimes I make jokes on my videos. :-)

    I didn’t know there was a Rose nebula. I’ll look into that!

  18. One day we will have a telescope powerful enough to see right back to the actual Big Bang. The question is, will we actually see the ” Vacuum Fluctuation ”tha triggered the B/B?

  19. Grand Lunar

    For a moment, I figured this was going to be about a race of aliens that hijack a starship and take it to another galaxy. Right? :)

    I had no idea so many alternate names existed for Sirius. Wow! All I knew was, of course, Sirius, and “The Dog Star”. Well, that’s the highlight of Q & BA; it provides interesting education.

  20. DrFlimmer

    Angelo, I regret telling you that we won’t be able to see the Big Bang what ever we do! The problem is that we can only detect electromagnetic waves (the entire spectrum of light). And the universe became transparent for light 300,000 years AFTER the Big Bang So this is the earliest point in the history of the universe we can see. And we SEE it. It is the Cosmic Microwave Background and it perfectly fits in the Big Bang Theory by now!

  21. jayem

    Phil…that was explained irrefutably, indubitably, decidedly, incontrovertibly…clear. I’ve had the HR catalogues for years now and consider them very useful for referencing…no matter what name a star or galaxy has.

  22. Gary Ansorge

    Gee, astronomers is the most funniest people,,,you should have consistant nomenclature, like physics,,,mu-meson,pi-mesons,quarks, cake-mesons,,,er, oops,,,maybe not cake,,,

    OK, so, I prefer everything be named after chocolate,,,

    Cool clarificatoin(???) Phil. Now I think I’ll just go back to bed,,,

    GAry 7

  23. David Vanderschel

    I suppose that some folks may appreciate these audio and video presentations. However, I don’t. It takes too long to listen to or view one, and I cannot skim over stuff I am already familiar with. Though the BA is offering these Q&BA episodes in many forms, he is not offering them in the form that I would find most useful – namely HTML text with links to the illustrations (which are relatively infrequent). Phil, I like you; but, after having seen more of it than I care for, your talking head is not particularly entertaining. Could you not also post the scripts (with links) you use for these presentations? I would read those; but I don’t see myself playing the videos or audios anymore. Posting the text of the Q&BA episodes would also create a more thoroughly searchable archive for these tutorial efforts. If you are actually ad libbing these programs, I imagine that there are folks who would volunteer to prepare transcripts.

  24. Gary Ansorge

    Virginia:Ah yes, Vista,,,another piece of crud from the Grate(no misspelling here) One,,,

    As soon as I can afford it, I’m getting a Mac.

    DSL may not be the fastest way to download, but it is fairly cheap. I have a 1.5 Mbit line which is fast enough for practical purposes, though for on line, real time video I should probably go to 6 Mbit. That’s in the wish bucket,,,

    The video is a cool way to expound upon the ineffable, Phil. Besides, passion for ones subject comes across better in a visual/audio mode than in HTML or other text. I say, keep going for it, Phil.

    GAry 7

  25. RAF

    The Bad Astronomer said: Due to my travel schedule, I am posting this one early.

    Going somewhere, BA? It sure is NOT on your calendar…”hint, hint”.

  26. Bee

    This is great! I never made the connection between Messier and messy, that’s funny actually :-)

    Totally off-topic question: how do you get the quality of the video to be so good? I’m trying to figure out how that stuff works, but doing so very inefficiently. If you have the time and don’t want to answer here, feel free to send me an email.



  27. Thank you for the info :)

  28. David Vanderschel Says: “Phil, I like you; but, after having seen more of it than I care for, your talking head is not particularly entertaining.”


    Virginia Says: “I√Ę‚ā¨‚ĄĘm in agreement with David Vanderscel√Ę‚ā¨‚ĄĘs comment: to some of us, video presentations are just a major annoyance.”

    Have we reached BA media burnout? Sartorial knowledge saturation? My only comment is that you don’t HAVE to watch them, although David’s suggestion of a text version would be helpful to those that prefer it.

    I don’t want to be speaking for Phil here, but if he does these spots the same way he did his talks at WordCon, there isn’t a script per se, just some bullet points that he talks from.

    – Jack

  29. Tukla in Iowa

    I love these little videos!

  30. Phobos

    Phil – Funny you didn’t mention StarRegistry names…

    (love these videos!)

  31. Melusine

    First off, I don’t think these videos are too long, in fact, they could be longer and it wouldn’t bother me – I think they’re engaging and something different than the usual posting. I also like that people point out Phil’s errors and/or add additional information; it means people are paying attention!

    One thing I knew (wow, I knew something the BA didn’t!) is what Irishman pointed out – the Rose and Rosette nebulas. Thanks, Irishman, you’ve been one of the most prolific commenters here since the start of this blog and you always have good and relevant information! :-)

    And what book is that? I hate not being to tell what it is. I wonder, too, does Mrs. BA and Little BA watch you do these? Or do they have to leave the room to keep from giggling out loud? I kind of wish you’d “share” Little BA – I’d love to see a father/daughter video. Being that some people are sharing these videos with kids, that might be fun. ~8-)

  32. A couple of things:

    1) I know about the Rosette nebula, of course. It’s a famous one. But it’s not the Rose nebula. Evidently there is a Rose Nebula. I knew of this nebula itself, but not the name.

    2) I marked Virginia’s post as spam, since it linked to a link farm.

    3) Transcripts of many of the Q and BA episodes have been made, but I haven’t uploaded them yet because I’m still trying to figure out how to organize all this. I’ll do it at some point. As Jack Hagerty pointed out, I don’t have a script to work from; this is all ad lib. Jon Voisey from The Angry Astronomer has sent me transcripts after I post the episodes, so I’ve got them, I just need to get organized.

    4) Bee, I just use a webcam and edit the file using Windows Movie Maker, one of the truly most awful pieces of crappy software it has ever been my misfortune to use. In the future I will use different software, but I’m too busy to learn it now. Eventually.

  33. Nigel Depledge

    Phil, what I think you were struggling for was this:
    “That which we call a rose, by any other name would smell as sweet…”

    Anyway, that was a good one!

  34. Drbuzz0

    Phil! You completely forgot that the names of stars are recorded in book form in the US patent office and…. oh yea… nevermind.

    I really liked that Q and BA, though. I assume that pretty much all the stars or other objects visible by the naked eye or a nominal telescope probably have been given some sort of label and cataloged by this point?

  35. Phil

    What a surprise when my tracking started to show hits from badastronomy.com.
    My first thought was W.T.F. did I do wrong.

    I was pleased to see you used one of my photos for your video blog .
    I was also very pleased to see the flickr creative commons license guidelines adhered to with a link as well.

    Not many people follow those guidelines so thanks also for being on the “up and up”.

    Best Regards from the middle of Canada

  36. Jeff, my pleasure. That was a great shot!


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