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CESDewar
GorillAstronomer


Reged: 01/16/05
Posts: 2085
Loc: Blue Ridge, GA, USA
The 'Eagle' Cluster (?!) new
      #1775368 - 08/13/07 06:28 PM Attachment (69 downloads)

Often, I like to just cruise the skies with relatively big binoculars (my 30x77mm Exceeds are my latest favorite for this) and always enjoy stumbling upon something I've not seen before.

So tonight I'm cruising around Saggitarius and stumble upon this gorgeous open cluster - it has all the appearance of a huge eagle coming in for a landing with its wings extended. Only I can find no designation for this cluster in the few star charts and maps I've looked at. It's pretty big - the fact that it completely filled the 2+ FOV of my binoculars made it especially noticeable (and the fact that the orientation was just "right") although many of the stars are not that bright.

I've shown below where this grouping is. It's always a bit dangerous posting something like this - when someone comes back and asks if it is just that I am unfamiliar with "Higginbotham 17" and makes me feel like a clod , but I would like to know the designation of this grouping as it is striking enough that it must surely have a good name! I'm sure that it has a Collinder or Trumpler etc. designation - so I'm just wondering if anyone here knows what it might be... Take a look at it - it will look best through 70mm binoculars or larger, although I had no trouble at all seeing it in my 18x50 Canons. It's worth a look...

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KennyJ
The British Flash


Reged: 04/27/03
Posts: 20139
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Re: The 'Eagle' Cluster (?!) new [Re: CESDewar]
      #1775419 - 08/13/07 07:09 PM

Stuart ,

I've long appreciated your observational prowess and willingness to share , but even more so , envy your ability to demonstrate so clearly what you have seen .

It seems that almost EVERY time I spend more than an hour or so looking at the night sky through binoculars or scopes , at some stage I come across " mini - constellations " or clusters that I've never seen recorded or reported as such !

Sometimes , I guess it's just in the eyes of the beholder !

Regards , Kenny

--------------------


Milton Wilcox R.I.P






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ronharper
Carpal Tunnel


Reged: 02/14/06
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Re: The 'Eagle' Cluster (?!) new [Re: KennyJ]
      #1776126 - 08/14/07 12:52 AM

CES,
I checked my SA2000, and although it doesn't show it, I had marked it at some time in the past with a grease pencil as a dotted circle, labeled ngc6744. Having just come in from observing on the first semi-clear night in ages and ages, and seeing your post, I ripped right back out, dark adaptation now blasted, but found it easily with 16x70.

Quite impressive, thank you! This eagle even has a beak and feet, in just the right places. Hmmm, you do have sort of an animal thing, right?
Ron


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Rich V.
Post Laureate


Reged: 01/02/05
Posts: 3143
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Re: The 'Eagle' Cluster (?!) new [Re: ronharper]
      #1776202 - 08/14/07 02:22 AM

Thanks for pointing this out, Steuart, it was fun looking at it! Your mapping skills are a treat.

Regardless if it's actually a cluster or just an asterism, the "eagle" form is quite easy to imagine. It is framed nicely through 16x70s as Ron already pointed out. To get an idea how it looked in your 30x77 I tried the 80mm scope at 34x. It looked great even with one eye! ;^)

Best regards,

Rich V

--------------------
Binoculars:
33/50/71/150x100 Saturn III, 22x70ED, 16x70 FMT-SX, 10x50 PCF-V, 10x43 DCF-SP, 10x35 EII, 7x35 E, 8x30 EII,
7x26 Custom, 8x23CF AS Diplomat, 6.5x21 Papilio
Scopes:
C9.25, TMB130SS, SV80S-LOMO 80/480
IDA member


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CESDewar
GorillAstronomer


Reged: 01/16/05
Posts: 2085
Loc: Blue Ridge, GA, USA
Re: The 'Eagle' Cluster (?!) new [Re: ronharper]
      #1776218 - 08/14/07 02:53 AM Attachment (35 downloads)

Quote:

...I had marked it at some time in the past with a grease pencil as a dotted circle, labeled ngc6744.



As near as I can tell, NGC6744 is a 15th mag galaxy in Pavo - A Southern hemisphere constellation - perhaps a typo for something else?

I'm glad to read a similar reaction to seeing it. It doesn't have a lot of bright stars, so aperture helps, but it seems sufficiently striking to me that it must be in someone's catalog. I've included a sketch of the major stars in the grouping that show the Eagle shape. This is how it appears around 11pm on this date.

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EdZ
Professor EdZ


Reged: 02/15/02
Posts: 18806
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Re: The 'Eagle' Cluster (?!) new [Re: CESDewar]
      #1776338 - 08/14/07 06:29 AM

There is a cluster designation plotted at 19h17mRA -1717m. Named Ru 147 (Ruprecht 147), it is listed as 48 arcmin in diameter with a population of 20 stars, the brightest being mag9. That's nearly exact on your spot. There's nothing else in the Catalogue even remotely close.

edz

--------------------
Teach a kid something today. The feeling you'll get is one of life's greatest rewards.
member#21


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PhilH
sage


Reged: 01/27/05
Posts: 442
Loc: Long Island, NY
Re: The 'Eagle' Cluster (?!) new [Re: CESDewar]
      #1776388 - 08/14/07 07:26 AM Attachment (54 downloads)

That's a great observation! Thanks for sharing it. I'm including a map of the area from Megastar to show its location a little more precisely. It's just north of the Sagittarius "teaspoon."

As EdZ mentioned, the group is identified as Ruprecht 147. The NGC/IC Project also notes that it is also NGC 6774 (as opposed to NGC 6744 mentioned earlier). There, Steve Coe mentions it is difficult to ID in his 13.1-inch telescope, and even questions whether it is a true cluster. Once again, this shows the power of binoculars over a telescope on certain objects!

I've got to add that to my list for the next night I'm out with the binocs, to revisit the area, since I really enjoy looking for these imaginative mini-constellations!

Phil

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Phil Harrington
Contributing editor, Astronomy magazine
Author: Cosmic Challenge || Star Watch || Touring the Universe through Binoculars || Star Ware || et al...
Binocular Universe
http://www.philharrington.net
http://www.observingsites.com
"Two eyes are better than one!"


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ronharper
Carpal Tunnel


Reged: 02/14/06
Posts: 2065
Re: The 'Eagle' Cluster (?!) new [Re: PhilH]
      #1776599 - 08/14/07 10:07 AM

Well, hey, the grease pencil mark was getting pretty smeared.
Ron


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CESDewar
GorillAstronomer


Reged: 01/16/05
Posts: 2085
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Re: The 'Eagle' Cluster (?!) new [Re: ronharper]
      #1776909 - 08/14/07 12:56 PM

Ok, I see NGC6774 - not sure why Starry Nights wasn't displaying that designation (I did have Starry Nights set to show all NGC objects) - but when I searched specifically for NGC6774, it then shows it. However, it also lists the size at 25 arc-minutes - which only covers the central portion, and not the eagle's wings or its feet which is what makes this grouping really striking.

EdZ - Ruprecht 147 - yes, I see Starry Nights lists that as a reference under NGC6774. However, Ruprecht 147 also lists the angular size of this cluster as only 25 arc-minutes, so it's also not encompassing the entire grouping here. This "eagle" grouping is quite a bit larger - I measure it at least 120' from tip to tip of the eagle's wings, and I count more like 50+ stars in that grouping that are visible in larger binoculars.

It looks like the designation of this cluster only includes the center of this grouping - perhaps because this is because the wings are actually just part of an asterism rather than the cluster itself(?).

But it would be easy to overlook the whole thing if the magnification were much above 40-50x or so. What made it so striking was that at 30x, it just about filled the whole FOV without any outside distraction, so the shape was even more obvious. I'm going to take a look at it tonight (which looks like clear skies and perhaps lower humidity) with my bigger Saturn III's.

BTW - in the course of looking at this, I did find this very useful master list of Open Clusters:
http://www.astro.iag.usp.br/~wilton/

I would expect a grouping like this to get a Collinder designation, but a search of all the Collinder objects shows nothing in that area. If you're reading this thread and haven't looked for it yet - give it a try - it's quite easy to find and I'd be interested in knowing if everyone else finds it as interesting as I did...

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Tony Flanders
Postmaster


Reged: 05/18/06
Posts: 8212
Loc: Cambridge, MA, USA
Re: The 'Eagle' Cluster (?!) new [Re: CESDewar]
      #1776933 - 08/14/07 01:15 PM

Quote:


EdZ - Ruprecht 147 - yes, I see Starry Nights lists that as a reference under NGC6774. However, Ruprecht 147 also lists the angular size of this cluster as only 25 arc-minutes, so it's also not encompassing the entire grouping here.




The book Star Clusters, by Archinal and Hynes, cites John Herschel's discovery observations of NGC 6774 as "a fine, large, loosely scattered cluster ... filling 2 or 3 fields" and Ruprecht's initial catalog entry, which describes it as 22' x 48', 66 stars mag 9 and fainter.

Based on inspection of Deep Sky Survey plates, Archinal and Hynes assign it a diameter of 45'.

Sounds like the NGC/IC page for NGC 6774 needs an update. Anybody feel like sending Corwin an e-mail?

It's great that you've rediscovered this neglected cluster! Kudos also to Phil Harrington for singling it out in Touring the Universe Through Binoculars. Like him, I'm itching to observe it myself the next time I'm out.

--------------------
Tony Flanders

First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.


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Glassthrower
Vendor - Galactic Stone & Ironworks


Reged: 04/07/05
Posts: 17931
Loc: Oort Cloud 9
Re: The 'Eagle' Cluster (?!) new [Re: Tony Flanders]
      #1777070 - 08/14/07 02:51 PM

Quote:



BTW - in the course of looking at this, I did find this very useful master list of Open Clusters:
http://www.astro.iag.usp.br/~wilton/






CES -

Thanks for that link to the master list of Open Clusters. That's good stuff.

Regards and clear skies,

MikeG

--------------------
Michael Gilmer - Member of the Meteoritical Society & Collector of Falling Stars.



☄ ⒼⒶⓁⒶⒸⓉⒾⒸ ⓈⓉⓄⓃⒺ ☞ www.galactic-stone.com


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camvan
Carpal Tunnel


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Re: The 'Eagle' Cluster (?!) new [Re: Glassthrower]
      #1777583 - 08/14/07 07:01 PM

the eagle is really nifty to look at! one that I thoroughly enjoy is the Swan Nebula. it looks like a swan, sitting on the water

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Cameron

"Aperture can only be replaced by even more aperture. Dark transparent skies cannot be replaced by anything else." - Stathis Kafalis

Intes MN66
Meade SN8
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CESDewar
GorillAstronomer


Reged: 01/16/05
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Loc: Blue Ridge, GA, USA
Re: The 'Eagle' Cluster (?!) new [Re: camvan]
      #1777806 - 08/14/07 09:02 PM

Well, my wife was saying I should have entitled this subject: The "Osprey Cluster(?!)" - so it wouldn't be confused with the Eagle Nebula (M16) - after all it's only 14 away from this cluster, but I figure how many people know what an Osprey is - and besides which, when I first saw this I said "Holy Smokes, this looks just like an eagle (ok, so I confess to actually using a bit more colorful language at the time ).

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Mark9473
Postmaster


Reged: 07/21/05
Posts: 6459
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Re: The 'Eagle' Cluster (?!) new [Re: CESDewar]
      #1781771 - 08/16/07 07:07 PM

CESD, I saw your "Eagle Cluster" tonight under favourable conditions - except that at my lattitude it never reaches high above the horizon. Still, I was able to make out some of it in my 7x50s. The cluster really showed well in my 80mm scope at 23x and up.

Did you notice that the brightest star on the east wing is a striking double? Nice and tight at 23x. Cartes du Ciel tells me this is Struve 715 and that the mag 7.1 and 7.9 components are 8".4 apart.

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Mark
Leica 8x20; Nikon 7x35; Vixen 8x42; Orion 15x63; Docter 15x60
WO Megrez II 80 FD / APM 107mm f/6.5 / Mewlon 210 on DM-6 + Berlebach Planet


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CESDewar
GorillAstronomer


Reged: 01/16/05
Posts: 2085
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Re: The 'Eagle' Cluster (?!) [Re: Mark9473]
      #1781954 - 08/16/07 09:02 PM

Quote:

Did you notice that the brightest star on the east wing is a striking double? Nice and tight at 23x. Cartes du Ciel tells me this is Struve 715 and that the mag 7.1 and 7.9 components are 8".4 apart.




Yes, in fact I had an updated post planned for tonight about that, but you beat me to it! Actually, the double you refer to is a triple system. There's a tertiary component at mag. 11.85 that is just 3" from the primary. I was not able to see this in my Saturn III's, even at 150x, but the seeing was poor and transparency poor too. Of course it may be an optical triple and not a bound system - I'll have to look this up to get more information on it. Starry Night shows the primary (HIP94823) a bit brighter at 6.6. It's probably too hazy tonight to see it, but I'm hoping tomorrow night may be clear enough to look at it in one of my bigger scopes.

And, we're not done as there is another nice double right next to it, just 6' away to the East. There are two components at mag. 7.8 (HIP94855) and mag 8.6 with a separation of 5" - this was nicely split in the Saturn III's at 54x. I scanned all the stars in the rest of the cluster and did not notice anything else of major interest.

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Tony Flanders
Postmaster


Reged: 05/18/06
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Re: The 'Eagle' Cluster (?!) new [Re: Mark9473]
      #1782590 - 08/17/07 08:01 AM

Quote:


Did you notice that the brightest star on the east wing is a striking double? Nice and tight at 23x. Cartes du Ciel tells me this is Struve 715 ...




I believe that's South 715, after the prolific double-star observer James South. Note also that the Pocket Sky Atlas plots a carbon star, V1942 Sgr, mag 7, 22' east of S 715.

--------------------
Tony Flanders

First and foremost observing love: naked eye.
Second, binoculars.
Last but not least, telescopes.
And I sometimes dabble with cameras.


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AstroTay
scholastic sledgehammer


Reged: 11/10/06
Posts: 958
Loc: Toronto, Canada
Re: The 'Eagle' Cluster (?!) new [Re: CESDewar]
      #1782594 - 08/17/07 08:02 AM

Thanks for the headsup. I saw it last night about 9:44pm. I first looked at the ISS flyby then turned my Cel Skymaster 15X70 to the teaspoon then star hopped to the "Eagle". The Chart was very useful. This is a nice Southern object view. Very pleasing and nice to look at.


Cheers

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Meade 10"LX200R w UHTC "Ocean Liner Anne" + wireless Autostar II
DSI Pro w CCD Color Filter Set
Celestron NexStar 102 SLT "SteamShip Anne"
Celestron SkyMaster 15X70 Binoculars "Can-U Anne"
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Mark9473
Postmaster


Reged: 07/21/05
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Re: The 'Eagle' Cluster (?!) new [Re: Tony Flanders]
      #1783118 - 08/17/07 12:33 PM

Quote:

Quote:


Did you notice that the brightest star on the east wing is a striking double? Nice and tight at 23x. Cartes du Ciel tells me this is Struve 715 ...




I believe that's South 715, after the prolific double-star observer James South. Note also that the Pocket Sky Atlas plots a carbon star, V1942 Sgr, mag 7, 22' east of S 715.




Thanks Tony for correcting my mistake; the Washington Double Star catalogue in Cartes du Ciel said "S 715", and the only name I knew that started with an S was Struve... I could have looked it up but it was late

--------------------
Mark
Leica 8x20; Nikon 7x35; Vixen 8x42; Orion 15x63; Docter 15x60
WO Megrez II 80 FD / APM 107mm f/6.5 / Mewlon 210 on DM-6 + Berlebach Planet


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Mark9473
Postmaster


Reged: 07/21/05
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Re: The 'Eagle' Cluster (?!) new [Re: CESDewar]
      #1783143 - 08/17/07 12:41 PM

Quote:

Starry Night shows the primary (HIP94823) a bit brighter at 6.6.




Could it be that this is an integrated magnitude for the two components together? In Carts du Ciel, the Hyparchos catalogue lists one star at mag 6.62 but notes the presence of the other component. The Tycho catalogue lists both stars separately, at mag 7.07 and 7.90, which is also what the Washington Double Star catalogue says.

--------------------
Mark
Leica 8x20; Nikon 7x35; Vixen 8x42; Orion 15x63; Docter 15x60
WO Megrez II 80 FD / APM 107mm f/6.5 / Mewlon 210 on DM-6 + Berlebach Planet


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Mark9473
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Re: The 'Eagle' Cluster (?!) new [Re: CESDewar]
      #1783892 - 08/17/07 07:39 PM

Quote:

there is another nice double right next to it, just 6' away to the East. There are two components at mag. 7.8 (HIP94855) and mag 8.6 with a separation of 5" - this was nicely split in the Saturn III's at 54x.




Not suprisingly, this one is called South 716. I've got the two components listed at mag 8.4 and 8.6. I saw it split tonight at 35x.

--------------------
Mark
Leica 8x20; Nikon 7x35; Vixen 8x42; Orion 15x63; Docter 15x60
WO Megrez II 80 FD / APM 107mm f/6.5 / Mewlon 210 on DM-6 + Berlebach Planet


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