September Challenge Object (OC) - M11

[iceman]

Hi all.

We'd love you to take part in the September Observing and Imaging Challenge (http://www.iceinspace.com.au/index.php?id=69,226,0,0,1,0). Please post your reports, sketches and deep-space images of M11 in this thread. Discussions about the images can also be in this thread.

Please ensure the images obey the posting guidelines when you attach them.

While it would be nice if the report, sketch or image were taken in the month of September, it's not essential so feel free to post older reports and images if you're unable to take some new ones.

We look forward to seeing your contributions!

[CosMos]

Wrote this a while ago. :thumbsup:

"The wonderful open cluster M11 is Scutum’s best deep sky object and one of the jewels of the heavens. Discovered by Gottfried Kirch in 1681, this group is easily seen in the smallest of apertures, lying on the northern edge of the Scutum Starcloud. Turning a telescope onto M11 will show hundreds of white stars, not unlike a globular cluster in form. Higher power will allow you to descend into the core and an intriguing sight is a black starless patch west of the central mass of stars. A 20cm aperture will show around 400 stars of 11th magnitude and fainter, including one of 8th magnitude near the central region whilst a large mirror will show at least that many again.

Admiral Smyth thought M11 resembled a "flight of wild ducks" hence its common name "The Wild Duck Cluster". The density of stars in this region is so great that stars near the centre are possibly only 1 light year apart. These are very luminous stars, as our Sun, if placed within this cluster, would shine at around 15th magnitude. The total luminosity of M11 is about 10 000 times that of our Sun and the combined mass around 2900 times. Trumpler, a specialist investigator of clusters wrote that"...at the centre of M11 theobserver would find about40 stars with parallaxes of 2" or more and which would appear from 3 to 50 times as brilliant as Sirius shines in our sky".

There are many dark obscuring nebulae scattered about this region, the most obvious being B119a and B111. Look north of M11 for two black spots shaped like kidneys and almost in contact. Separating these two fine dark clouds are a number of 8 th to 10 th magnitude stars.

Another impressive and extended cloud lies around 0.5º southeast of M11. Barnard 114-118 blends together as a long inky black lane contrasting brilliantly with the surrounding bright starfield. Barnard 103 is a 1º wide cloud lying midway along a line joining alpha and beta ."

[dhumpie]

Very nice CosMos! Now its my turn :) This is one of the prettier open clusters in that it is more compact, covering a much smaller slice of the sky. In fact it does resemble a very loose and odd shaped globular cluster! But this also works against it as you need slightly more aperture to resolve it. The cluster looks very pretty from memory in my 76mm newt. There is a standout single star surrounded by a unresolved haze in the shape of a V (hence the wild duck moniker) at low power. Bumping up the power brings a few more stars into view (see my sketch). I get the same impression in my Orion 80ST. The cluster is very nicely resolved (all stars visible) in my C6 and also in my 102ST. In my 15x70 binocs, I see pretty much what I mentioned earlier with a single star surrounded by and unresolved haze (well maybe 1 or two specks come through). I have a more detailed sketch that I will upload later. For now see:

http://www.geocities.com/dhumpie/dastro/m11.jpg

Cheers,
Darren

[iceman]

Excellent reports Cosmos and Darren!

[RapidEye]

M11 is a dandy little OC – definitely one of my favorites. Around here, it gets about 50 degrees above the horizon, so its one of the finer Southern Summer DSO’s for us on this side of the equator. :cool:

My general appreciation for this one is that it almost appears like a combination of a GC and an OC. Even with a 10” scope, it still has that “misty” feel that many of the fainter Globs do, but much larger than most Globs. In 10x50 binoculars, its just a large misty patch with one bright star in the middle, but quite noticeable.

Here is my log for last night using my 4.5” F8 Dob
08/31/05 (it was Sept 1 down in Oz) LM 5.0, Std 3/5
30mm Ultima – 30X
Looks nice tonight in the 4.5” – better than the last time I saw it in this little guy. Prominent “Lead Duck” is quite bright, but with direct vision, most of the cluster is a faint mist. With averted vision, it dazzles with stars! The dark central area isn’t as prominent as it is with the 10” – looks almost donut like, but not quite. Very nice with AV.

Here is my log from about a week ago using my 10” F5 Dob
08/24/05 LM4 .5, Std 3/5
14mm Pentax – 89X
Nice OC! Very pretty. Next to the bright star in the middle, there is a “dark hole” where only a faint handful of stars appear. With averted vision, a ton jump out – neat effect.

The fade in/out effect with AV was a lot of fun - very good working example of how the fovea in our eye operates :thumbsup:

In my 4.5", the V pattern really doesn't come through until I use AV. With the 10" it is quite clear not matter how you look at it :scared2:

[dhumpie]

Nice report Rapid :) Have you noticed at high magnification how there are "dark lanes" running throughout the cluster? Then again maybe its my brain making some funny shapes and patterns :)

Darren

[RapidEye]

I've not taken it any higher than 89X - but plan to next time out =-)

I don't think your seeing things that aren't there. I clearly see a darker area in the middle of the cluster and I wouldn't be suprised to see some dark lanes under further study at higher magnification with my 10".

I was looking at it again last night while I was working through my carbon star list. I just had the 4.5" out 'cause I was trying to be more mobile (had to work around some trees for the carbon stars I was looking for). You also don't need lots of aperture to appriciate most of the carbon stars I've found so far.

Anyway, here is my log entry for last night:
09/01/05 LM 5.0, Std 3/5
4.5" F8 Dob and 14mm Pentax XW – 64X
Doesn't look as good tonight. The mugginess is greying up the background too much. It is still pretty and the V pattern stands right out. The dark area still isn't as pronounced as I recall the other night (in the 10"), but it is still visible. Averted Vision helps a lot.

[RapidEye]

There is a very interesting carbon star right near M11. Its just a couple of FOV's away, so while you are in the neighborhood - see if you can find S Scuti.

http://www.seds.org/Maps/Const/Data/scutum_tab.html

Its not the reddest of the carbon stars, but is a pretty salmon color sitting in an interesting field of blue and white stars. Its worth the minimal effort to find (so close to M11).

If you've not looked for Carbon stars before, be warned: they are easy to overlook! That color doesn't jump right out at you like a faint fuzzy does, so work slow.

Also, be warned: once you've seen a couple, you might get hooked and will spend endless hours on the internet compiling lists of carbon stars :doh: . If you get to that point, drop me a line - I've got a couple of very extensive lists compiled already :P

[davidpretorius]

great reports guys, have added the bonus to the list

[ving]

QUACK QUACK QUACK!!!

my thrird animal for the night...
the bug: squashed
the starfish: ripped its legs off
the duck: er... cooked?

interesting cluster this one. someone mentioned dark lanes, well i followed these around for a while trying to make a shape out of them (preferably a duck shape) and i kinda did... well kinda.
I think i need to work on my imagination a bit. anyhow its quite bright and shapey(?).
gah! I need some pics of it to see if i got the duck shape or not.

anyhow, enough of these dang animals guys!!!! :P

[EddieT]

Hi guys,
I have a picture of this one taken in July last year. It was the first image with the Mak-Newt.

I've attached a small version but have larger versions on my web site if you want to get really up close and personal

(Big ~600kb)
http://astroshed.com/ice/m11rgbm.jpg

(Biggest ~1.2Mb)
http://astroshed.com/ice/m11rgbl.jpg

[ving]

thanks eddie!
great images.... but now i cant see any ducks at all :(

[EddieT]

That's always a problem with deep exposures. Whatever shape was seen visually tends to disappear in a blaze of glory :)

[astro_south]

Darren

Out at Leyburn last week I checked this out in the 12.5" and I noticed a lot of rectangular structure in the alignment of the stars and places where stars were absent. I found this quite striking. If I get a chance I will try and sketch it this weekend (from Brisvegas) and see if I can reproduce the view at the eyepiece.

Nice piccy Eddie :thumbsup:
Great reporting Cosmos, Darren, Jim and Ving

[RapidEye]

LOL - the cluster gets its name not because it looks like a duck, but rather because it looks like a FLOCK OF DUCKS in flight. :lol: Dunno what they do down under, but here, when the ducks and geese migrate, they fly in a big "V" pattern for aerodynamic efficiency.

The cluster has a V shape too it, with the brightest star near the head of the flock (narrow end of the V). The dark area is the hollow in the middle of th "V" where there are no "ducks".

I was studying this one last night using my 10x50 Binoculars and was suprised how much I could acutally see. While I couldn't make out the dark area in the middle, I could easily see the triangular shape and with averted vision, I thought I could see a bright point near the head of the V.

Very nice OC, no matter what the instrument.:thumbsup:

[seeker372011]

Not surprisingly M11 through a short tube achromat-an ETX 70-looks nothing like eddie's fine image of this cluster

[RapidEye]

No, but it actually shows the "V" pattern better and the dark area in the middle better than his does because his goes so much deeper. :thumbsup:

Ving - see that bright star on the left side of the cluster? The cluster comes to a point just below it and fans out sorta like a "V" to the right. Sorta like a flock of Ducks or Geese in a migration flight!

Nice shot Seeker!

[ving]

yup, i can see it now....

but

ok eddie, i know its kinda vague but then so am i at times, but if yo follow the dark areas I see a duck kinda. yeah my imagination runs a bit wild sometimes :rolleyes:

i coppies narayans and oulined the "duck" including wing in red. just view narayans to see it with out the red line. I get a more defined shap in my scope tho

[RapidEye]

Stop drinkin' that cheap stuff before you observe :drink: and It'll help :poke:

[ving]

you gunna tell me that you dont see the duck? :)
its there i tells ya!

[ving]

hang bout guvner! you aint eddie! watsit all bout then!
sorry bout that Mr. Eye

[dhumpie]

Wow all the nice reports and great sketches and images. This one seems to be the most popular MOC object :) But it is a very nice and rich cluster...

Darren

[ving]

do you see a duck darren?

[CosMos]

The dark lanes are not a figment of the imagination. Sir John Herschel saw " a beautiful irregularly R cl 10' or 12' diam. The stars are all 11m except one = 9m whose place is taken. Examined with high magnifiers [I have often viewed it with 800 and even 1200]; it is broken into 5 or 6 distinct groups with rifts or cracks between them."

The overall shape of the cluster gave the appearance of a flock of ducks to Smyth " This object, which somewhat resembles a flight of wild ducks in shape, is a gathering of minute stars, with a prominent 8th-magnitude in the middle, and two following; but by all analogy these are decidedly between us and the cluster." So, no duck or ducks can be seen :shrug:

Rich :cool:

[dhumpie]

Hey David,

I do see the triangle of migrating ducks when I look at it through less aperture (i.e. Orion 80ST low mag or 15x70 or 10x50's)and magnification. It resembles nothing like a flock of ducks when seen in my C6 at mags of above 100X. Too richly resolved....

Darren

[ving]

fair enough, seems its my imagination thats running wild and not the ducks...

[RapidEye]

I made another pass at M11 the night before last with my 10" Dob.

I decided to run the power up a bit, and dropped my 10mm Pentax XW into the scope (125X). It really frames the cluster nicely at that power and makes the dark areas really DARK!

One thing I noticed that I hadn't caught before: to the east of the cluster, next to the bright star, there is a dark lane. Just east of that lane, is a very fine single file line of faint stars arainged into a V pattern as well. To me, that line looks more like the V of a duck flock than the rest of the cluster did.

In fact, the main section of the cluster appeared more like a hollowed out pentagram.

Both the dark area in the middle of the pentagram and in the lane between the single file line and the bright star had what appeared to be a faint misty, almost globular cluster that appears to be set in the background.

The more I study this cluster, the more I like it! :thumbsup:

Too bad photos of it just don't look the same as it does visually :rolleyes: