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Cosmic Challenge: M13's propeller

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#1 PhilH

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Posted 01 July 2017 - 09:37 AM

In last month's column, we paid a visit to the Moon and the crater pair of Messier and Messier A. This month, we head back out into deep space to examine one of the most spectacular entries in Charles Messier's catalog: M13, the Great Hercules Globular Cluster.

Click here to view the article
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#2 Gipht

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Posted 01 July 2017 - 10:07 AM

I am  new to astronomy  and really appreciate the type of write up given here that discuss facts and give historical context. Thanks for a great article.   I  am assuming the purpose is to generate interest?  Is there a location where people post their Photo's or sketches?


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#3 HarryRik9

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Posted 01 July 2017 - 11:06 AM

The presence of dust in globular clusters is well known but is controversial as to whether the dust is inside the clusters or is foreground dust seen in projection. I think the propeller dust formation is foreground dust. I discuss this in this paper: http://www.naturalph...dust-filaments/


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#4 rekokich

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Posted 01 July 2017 - 12:12 PM

M13 NGC6205 Herc 20170426-ELs TS100-812 2x 7x240''-1600-o-cls-65F.jpg


#5 james7ca

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Posted 04 July 2017 - 12:29 AM

Phil, thanks for the article.

 

Here is a link to a thread on CN that has both an RGB and high resolution luminance image that shows the "propeller" on M13:

 

  https://www.cloudyni...s/#entry7893318

 

The part of the dusk lane that appears at about the 11 o'clock position is very well defined (best shown in the last post, #6).


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#6 PhilH

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Posted 04 July 2017 - 03:08 AM

I am  new to astronomy  and really appreciate the type of write up given here that discuss facts and give historical context. Thanks for a great article.   I  am assuming the purpose is to generate interest?  Is there a location where people post their Photo's or sketches?

Absolutely.  There are many, many forums here on CN for posting photos, sketches, and observations.  Probably best to start by visiting those under the Astrophotography and Sketching heading.  For general discussions of observations, head over to the Observing forums.

 

And welcome to CN!


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#7 The Ardent

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Posted 05 July 2017 - 01:01 AM

I've observed M13 several times with an 18" dob. There are many more dark lanes around the periphery. Sometimes they appear to connect so that the propeller appears to be just one corner of a pentagon , or hexagon surrounding the core. This is also visible in the photos posted and linked to above.
Also with large aperture I can see some of the brighter stars as a pale orange color.
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#8 TOMDEY

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Posted 05 July 2017 - 09:50 PM

Hmmm... I'll look next chance! Never scrutinized with that darker propeller in mind, but certainly noticed real patterns of stars that look like tendrils. And always wondering to what extent it could be some sort of dynamic associations and/or our natural tendency to see patterns in chaos. I've got 16-in binos and even bino Night Vision capability eyeps. That enhances dark nebulae magnificently. So excited to look for the propeller. Intend to report back. Tom


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#9 dolphinzilla

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Posted 08 July 2017 - 06:59 PM

I captured this on July 1, I noticed after reading this challenge I had captured the propeller  https://www.astrobin.com/302412/0/


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#10 Dave Mitsky

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Posted 09 July 2017 - 11:50 AM

Here's my BRT image of M13 showing the Propeller or Mercedes-Benz symbol on the left and the X of brighter stars near the cluster's core.  North is up in the image.

 

Dave Mitsky

Attached Thumbnails

  • M13 25% Reduction CN     5-22-14.jpg


#11 Max Power

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Posted 10 July 2017 - 11:56 AM

I don't see nothing but a ball of stars with my 10". If they only show up in photos don't you think they are photo enhancement artifacts?

Edited by Max Power, 10 July 2017 - 11:56 AM.


#12 turtle86

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Posted 10 July 2017 - 01:17 PM

I don't see nothing but a ball of stars with my 10". If they only show up in photos don't you think they are photo enhancement artifacts?

 

I'm not sure how much aperture is needed but I've seen the propeller numerous times in my 18". The propeller isn't a photo enhancement artifact.



#13 micromaxcomputer

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Posted 11 July 2017 - 03:30 PM

M13n


#14 micromaxcomputer

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Posted 11 July 2017 - 03:32 PM

WOW never knew I captured the propeller! Thanks Phil.



#15 EverettQ

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Posted 12 July 2017 - 08:35 PM

https://everettquebr...s-cloudy-again/

 

34830491986_877c4661e7_b.jpg


Edited by EverettQ, 13 July 2017 - 10:35 AM.

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#16 nicknacknock

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Posted 13 July 2017 - 09:55 PM

An incredibly clear image of the propeller



#17 jrbarnett

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Posted 15 July 2017 - 04:16 PM

Phil, great, fun article.  Thanks for sharing it with us.

 

- Jim


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#18 jrbarnett

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Posted 15 July 2017 - 11:42 PM

I captured this on July 1, I noticed after reading this challenge I had captured the propeller  https://www.astrobin.com/302412/0/

Great image of not just the Propeller, but also the lower portion of that "hexagon" structure The Ardent references in a post above.  The Prop in your image forms the lower left "corner" of the hexagonal structure.  Awesome capture.

 

- Jim


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#19 dswtan

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Posted 16 July 2017 - 01:16 PM

I got it on this 2014 capture -- see left. Not the most subtle processing in this one, but the propeller is clear! https://www.flickr.c...an/15107898662/


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#20 jrbarnett

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Posted 16 July 2017 - 01:52 PM

I got it on this 2014 capture -- see left. Not the most subtle processing in this one, but the propeller is clear! https://www.flickr.c...an/15107898662/

Excellent!

 

- Jim



#21 EJN

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Posted 17 July 2017 - 10:00 AM

It show up well in this image I took with a 6" f/5 Newtonian:

 

gallery_12877_7876_187936.jpg

 

 



#22 TOMDEY

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Posted 19 July 2017 - 01:18 AM

OK, here I am, two weeks later; Yippee! Had been quite some time since I used the JMI RB-16 binos. To my surprise, everything worked fine. I warmed up on a few galaxies, nebulae, and then globulars M10, 12, 14. Delighted with great sky darkness and seeing, M13 high, SQM 21.3 in the direction of M13. I savored the globular at 96 and 141x. Both showed the propeller nicely... the lower mag seeming more distinct, but the higher mag confirming that there were "no stars" in the propeller. Then I went to the Night Vision eyepieces. Woo Hoo! The propeller is much more apparent, Much more! Still trying to understand ~why~ that would/should be so, but the affect is really significant. Here are some possibilities: NV is blue-deficient, but sees well into the NIR. NV picks up about a magnitude in threshold. NV displays brightly, so can look directly using central, photopic vision. True binos significantly improve contrast discrimination. So, this admittedly grandiose set-up is highly-optimized for the challenge. Had this been an experiment ~in the blind~ "Here's a globular, sketch what you see." I think I would not have seen the propeller as such with the regular eyepieces... I'm pretty sure I would have sketched it as a Y-shaped dearth with the NV. Further: Although the NV frequently shows structure to advantage... it is not as satisfying as examining the stellar photons directly to the retina.  Conclusion: Thanx for the challenge. Now my equipment and attitude are ready for more observing! Tom


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#23 Astro-Master

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Posted 19 July 2017 - 06:54 PM

What are night vision eyepieces?  Who makes them?



#24 TOMDEY

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Posted 19 July 2017 - 09:02 PM

Tom here, It's actually Gen 3 Night Vision adapted to a nice, simple 1.25-inch tube. Even takes 1.25 filters! So, you have to go that route. The BEAUTY is that feels Exactly like using a regular eyepiece, cept you "turn it on." Here's a picture. I can provide more info. I have three identical ones, two that I most use and one "backup." Cost is less than $2000 each... YIKES!  Picture attached shows it next to a TeleVue 10mm Delos.  Tom  Ummm... I have NO IDEA how to attach my image to this perplexing "user friendly" comment... Nuts. Anyway, it weight about as much as a Delos and is SPECTACULAR in use!  Tom  PS if anyone can tell me how to attach an image to a comment, please let me know. This CN is way too fancy, to the point of losing me.  Tom



#25 okietwisterdan

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Posted 25 July 2017 - 01:44 PM

I saw it a few nights ago with my 12 inch dob!  I never even knew to look for it.  Thanks Phil!


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