Coathook to the stars
In the constellation of Vulpecula, the fox – located high in the sky this time of year for northern hemisphere observers – is a fun little asterism: a collection of stars formally known as Brocchi’s Cluster, or Collinder 399. Greek astrophotographer Anthony Ayiomamitis took a grand picture of it just a few days ago that I have to share with you:
[Click to enhaberdasherate.]
It’s very pretty, isn’t it? The asterism itself is composed of the ten or so brightest stars you see; the rest are background stars. It’s most likely not a true cluster; that is, the stars may be at different distances and not physically associated with one another.
Still, this so happens to be one of my all-time favorite objects in the sky. Why? Because of the shape of the cluster: it really looks like a coathanger! If you don’t see it, I drew lines between the stars in question in the image inset here.
Now you see it, right? Astronomy Picture of the Day featured a different shot of the Coathanger in 2008, too, which is worth a look.
This group of stars is pretty big – three times the width of the full Moon on the sky – and bright, making it really easy to spot with binoculars. In fact, when I was younger I stumbled on it myself by accident while scanning that part of the sky with my telescope. It was obviously shaped like a coathanger, and I was delighted to find out that’s what everyone called it.
In fact, now that I think about it, it’ll be very well placed for observing in September, making it a great target for folks coming to Science Getaways. That would be fun. But if you have clear skies this time of year, it’s easy to find, about a third of the way from the bright star Altair to Vega, in the Summer Triangle. Give it a shot!
Image credit: Anthony Ayiomamitis, used with permission.
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I saw this one (I think) through binoculars when I was a kid. If you turn the picture upside down, it resembles a front elevation view of the Enterprise, 1701.
That’s no hanger, that is Gandalf the Grey’s hat!
Why does the “hook” face different directions in the picture from Anthony and the one taken in 2008?
What is the difference between an asterism and a constellation?
My god, its full of stars!
#4 Carl: Asterisms are recognizable patterns of stars. Constellations are defined areas of the sky which contains asterisms. Their names come from asterisms defined by someone who thought some of the stars looked like something, e.g., Ursa Majoris, the big bear.
When I bought my first real telescope (8″ Newtonian) this was the first deep sky object I looked at. It was kind of upsidedownish so it took me a while to make a coat hanger out of it though.
I see a man wielding a scythe.
But then I’m weird.
@3 Matt
“Why does the ‘hook’ face different directions in the picture from Anthony and the one taken in 2008?”
Images in telescopes get flipped differently, depending upon the type of telescope. Some rotate the image 180 degrees, while others do a mirror image.
If you want to compare two photos from different telescopes, you often have to rotate, crop, and sometimes mirror image one of the photos to make the orientation match.
+1 Gandalf’s hat
My favorite is the Owl Cluster (NGC 457). Much more dramatic than a plain old coat hanger, if you ask me.
I stumbled across this one myself at a star party just this past Saturday! As most of my time is spent under gloomy city skies and none of my star charts seem to label this asterism, I was completely taken by surprise when it appeared within my telescope’s field of view. In excitement, I announced loudly, “hey, there’s a coat hanger near Altair!,” to which a more experience astronomer replied, “yep, there’s a coat hanger up there!”
I think it looks like a big tidal wave. Where is the surfer?
“No, I wasn’t doing that with a coathanger. I just locked my keys in there.”
Phil said that these stars are “most likely not a true cluster; that is, the stars may be at different distances and not physically associated with one another.”
Why is it that we don’t know for certain? Am I mistaken? … (likely so)… But I thought we could determine movement and distance of stars. Someone please enlighten me.
Thanks!
Do enjoy your site. You are NOT a bad astronomer! Admittedly occasional corny humor, but but still a very informative site. Thank you.
From a former kid astronomy buff — like 55 years ago. Walked the barrel, grinding and polishing, “constructing” a six inch Newtonian.
Now for the question. What is “high in the sky”? On the horizon toward the North or up at the zenith? Sorry. Serious question from a senile 70 year old.
This Coathanger asterism is also known as Brocchi’s Cluster or / and Collinder 399 among other things and has been discovered independently quite a few times by different people as it’s wikipedia page (linked to my name here) notes.
@14. Curt – From that wikipedia entry :
The BA might perhaps have been using an older source thus explaining that uncertainty.
Jim Kaler’s excellent ‘Stars’ website also has a great entry on this asterism noting that three of its stars have Flamsteed numbers – specifically 7, 5 & 4 Vulpeculae.
^ See :
http://stars.astro.illinois.edu/sow/cthng-t.html
&
http://stars.astro.illinois.edu/sow/vul-t.html
Which give the Kaler’s ‘Stars’ links to the Coathanger asterism and Vulpecula constellation more broadly including photographic findercharts.
Wikipedia page for 4 Vulpeculae is here :
http://en.wikipedia.org/wiki/4_Vulpeculae
Noting it is an orange giant star about 235 ly distant whilst 7 Vul is a B5 blue dwarf star located 760 ly away and 3 Vul is a B6 type blue giant star located 400 light years away as noted on their respective wiki-entries and the wiki- list of stars in Vulpecula which is linked to my name here.
I presume the other un-Flamsteed numbered stars of the Coathanger / Brocchi’s Cluster / Collinder 399 would have other star catalogue designations – SAO / HD / HIP (etc ..) numbers but not sure what they are or their types and distances.
PS. Almost forgot 5 Vulpeculae – the last of those Flamsteed lettered Coathanger stars is a Sirian type A0 V star located 218 light years away.
Clearly these stars are at very different distances and as Brian A. Skiff of Lowell Observatory noted :
Info from the table incl. there added too btw. Good article by on the non-cluster-ness of Brocchi’s Cluster / Collinder 399 / the Coathanger if folks can find a copy somewhere.
BTW. Red giant Anser (or shall we call it the goose star!) the lucida or brightest star in the constellation seems to be a member of the Arcturus stream, a group of stars with high proper motion and metal-poor properties thought to be the remnants of a small galaxy consumed by the Milky Way – Arcturus of course being the brightest example of that group in our skies! (Wiki-link to source in my name here.)
@14 Curt:
In addition to the material noted by MTU above, here’s a link to a 1998 study, again using Hipparchos data, that found Collinder 399 to be a chance alignment of stars and not a bound cluster: http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1998A%26A…340..402B&db_key=AST
@ Messier Tidy Upper…
Just now came back to check for responses. A belated, but hearty “thank you” is certainly in order.
I’m overwhelmed at how much has gone into studying these stars, and how difficult it’s been to accurately measure their movements and distances. I really thought it was a “simple” matter of parallax observation and red-shift determination. I should have known better. And now I do.
Again… thank you.
@ ^ Curt : No worries. Cheers!
@19. Jon Hanford : Thanks for that.
@15. Bill Gresho :
Not *that* senile I think! Depends where you live (latitude esp.) and what time of night it is but usually I think “high in the sky” refers to being closer to zenith rather than more northerly. Sometimes o’ course its both!
(Sorry, meant to answer that last night and forgot. No need to apologise for asking questions – some of us here actually love answering them!
[Raises hand.] )