APOD: Cocoon Nebula Wide Field (2014 Sep 18)

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APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by APOD Robot » Thu Sep 18, 2014 4:07 am

Image Cocoon Nebula Wide Field

Explanation: In this crowded starfield covering over 2 degrees within the high flying constellation Cygnus, the eye is drawn to the Cocoon Nebula. A compact star forming region, the cosmic Cocoon punctuates a long trail of obscuring interstellar dust clouds. Cataloged as IC 5146, the nebula is nearly 15 light-years wide, located some 4,000 light years away. Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by the young, hot stars and blue, dust-reflected starlight at the edge of an otherwise invisible molecular cloud. In fact, the bright star near the center of this nebula is likely only a few hundred thousand years old, powering the nebular glow as it clears out a cavity in the molecular cloud's star forming dust and gas. But the long dusty filaments that appear dark in this visible light image are themselves hiding stars in the process of formation that can be seen seen at infrared wavelengths.

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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by BDanielMayfield » Thu Sep 18, 2014 4:32 am

This image shows very well how dust reddens starlight that passes through it. Notice how in the upper left and lower right corners there are dust free areas where most all of the stars appear blue. You can discern the boundary of the dust cloud by how it reddens the light form background stars. Where the dust is thickest, no visible background light can pass through and the sky looks totally dark.
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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by Markus Schwarz » Thu Sep 18, 2014 7:32 am

BDanielMayfield wrote:This image shows very well how dust reddens starlight that passes through it. Notice how in the upper left and lower right corners there are dust free areas where most all of the stars appear blue. You can discern the boundary of the dust cloud by how it reddens the light form background stars. Where the dust is thickest, no visible background light can pass through and the sky looks totally dark.
I am glad you pointed that out, because I would have missed it otherwise :thumb_up: The Cocoon Nebula seems to be surrounded by a dust cloud that appears as a "smudge" and blurring some background stars. This cloud appears to have a sharp edge (in particular visible at the left and lower-left). I wonder if this edge is real, or if it is an artifact produced by combining several images.

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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by geckzilla » Thu Sep 18, 2014 7:57 am

I'm not sure what you mean by sharp edge but it's easy to tell what's an artifact and what's really there by comparing it to existing images. Here is another one, conveniently at the same orientation and set of filters.
http://apod.nasa.gov/apod/ap120913.html
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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by Boomer12k » Thu Sep 18, 2014 8:23 am

Oh my....it is full of stars.

What a great Wide Field shot.

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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by rwlott » Thu Sep 18, 2014 11:44 am

geckzilla wrote:Here is another one, conveniently at the same orientation and set of filters.
http://apod.nasa.gov/apod/ap120913.html
Another one? To my untrained eye, it is the same image; certainly the description, including all the links, are exactly the same. I've been a long-time, though somewhat casual viewer of APOD—nigh on since the beginning—but until now I didn't realize that entries were every repeated without some explanation of the fact.

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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by Ann » Thu Sep 18, 2014 12:09 pm

It's a fine picture. I've always liked the fact that the Cocoon Nebula was born at the end of a long trail of dust and gas.

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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by starsurfer » Thu Sep 18, 2014 12:15 pm

rwlott wrote:
geckzilla wrote:Here is another one, conveniently at the same orientation and set of filters.
http://apod.nasa.gov/apod/ap120913.html
Another one? To my untrained eye, it is the same image; certainly the description, including all the links, are exactly the same. I've been a long-time, though somewhat casual viewer of APOD—nigh on since the beginning—but until now I didn't realize that entries were every repeated without some explanation of the fact.
They're both two completely separate images taken by two different people.

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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by starsurfer » Thu Sep 18, 2014 12:16 pm

I think the description should have mentioned its cluster. Is there usually a word limit?

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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by bronco-busted » Thu Sep 18, 2014 4:09 pm

individuals who hav healthy vision can try viewing a double image of this picture to give a 3 dimensional effect. the well balanced combination of cloud of dust and gas in the foreground and the luminous star fields in the background offer an opportunity to view the image in 3d. it is uncertain whether the cocoon nebula is born of the dust and gas clouds spanning the image or whether the dust and gas are a product of the cocoon nebula's internal activity. motion is clearly involved. the cocoon nebula appears to be plunging through the interstellar medium leaving a trail of dust and gas behind - somewhat like a comet.
this item must be compared with objects which involve similar stellar dust and gas structures, such as that found in the field of view of antares.

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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by rwlott » Thu Sep 18, 2014 5:08 pm

starsurfer wrote:
rwlott wrote:
geckzilla wrote:Here is another one, conveniently at the same orientation and set of filters.
http://apod.nasa.gov/apod/ap120913.html
Another one? To my untrained eye, it is the same image; certainly the description, including all the links, are exactly the same. I've been a long-time, though somewhat casual viewer of APOD—nigh on since the beginning—but until now I didn't realize that entries were every repeated without some explanation of the fact.
They're both two completely separate images taken by two different people.
Yes, I realize that they are two different images, What I should have said was that "they are virtually identical to my untrained eye." But I guess my main point is in my surprise that the same description has been used for both.

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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by geckzilla » Thu Sep 18, 2014 5:16 pm

Description recycling happens a lot. Sometimes a little trouble happens because something that needed to be updated, like a date, wasn't modified to fit the new picture.
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Re: APOD: Cocoon Nebula Wide Field (2014 Sep 18)

Post by starsurfer » Fri Sep 19, 2014 12:21 pm

rwlott wrote:
starsurfer wrote:
rwlott wrote:
Another one? To my untrained eye, it is the same image; certainly the description, including all the links, are exactly the same. I've been a long-time, though somewhat casual viewer of APOD—nigh on since the beginning—but until now I didn't realize that entries were every repeated without some explanation of the fact.
They're both two completely separate images taken by two different people.
Yes, I realize that they are two different images, What I should have said was that "they are virtually identical to my untrained eye." But I guess my main point is in my surprise that the same description has been used for both.
To me both images look totally different with a few similarities. In the older one, more background hydrogen alpha nebulosity is visible. Also the APOD editors are busy guys, so I guess they reuse the same text sometimes and maybe why they also select images of deep sky objects that have been featured previously.