APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

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APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by APOD Robot » Tue Aug 06, 2013 4:07 am

Image In the Vicinity of the Cone Nebula

Explanation: Strange shapes and textures can be found in neighborhood of the Cone Nebula. The unusual shapes originate from fine interstellar dust reacting in complex ways with the energetic light and hot gas being expelled by the young stars. The brightest star on the right of the above picture is S Mon, while the region just below it has been nicknamed the Fox Fur Nebula for its color and structure. The blue glow directly surrounding S Mon results from reflection, where neighboring dust reflects light from the bright star. The red glow that encompasses the whole region results not only from dust reflection but also emission from hydrogen gas ionized by starlight. S Mon is part of a young open cluster of stars named NGC 2264, located about 2500 light years away toward the constellation of the Unicorn (Monoceros). Even though it points right at S Mon, details of the origin of the mysterious geometric Cone Nebula, visible on the far left, remain a mystery.

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by owlice » Tue Aug 06, 2013 4:10 am

Ah, I was hoping this would become an APOD as soon as I saw it!! Lovely image!!
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Beyond » Tue Aug 06, 2013 4:17 am

Ah, the cone nebula. I'll have a two scoop strawberry cone, please. And a bone for the "a mystery" link.
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by musiccaptain » Tue Aug 06, 2013 4:31 am

My unschooled imagination sees a young star in its tight natal nebula blocking the radiation of the bright nearby star to form the cone; still more interesting is the crescent-like object to the left and below the cone's head.

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Ann » Tue Aug 06, 2013 6:20 am

This is indeed a great APOD! :D :D :D

The colors are not only wonderfully beautiful but also "true", so that we would see them just this way if the sensitivity of our eyes was enormously enhanced. (Of course, if our eyes were this sensitive, we couldn't spot the colors of the nebulosity at the same time as we looked at the stars, for the same reason that we can't look at the solar corona unless the blinding light of the disk of the Sun is blocked by, say, the disk of the Moon.) Anyway, this picture is wonderfully esthetically pleasing.

But the details it reveals in the gas and dust structures in this area are also fantastic. For example, this picture clearly shows the Fox Fur nebula evaporating, so that we can be sure that the Fox Fur is the source of the dust that reflects the blue light of S Mon and creates a blue reflection nebula.
mage Credit: NASA, JPL-Caltech, P. S. Teixeira (CfA)
As for what causes the Cone Nebula, we may note in the infrared image at left that there is a lot of star formation activity not far from the Cone Nebula itself. There is a very bright infrared source near the Cone Nebula which appears to have no visual counterpart. Since star formation is accompanied by some ultraviolet emission, I would guess that this source at least contributes to the sculpting of the Cone Nebula.

I have stared with fascination at a yellow star at center left in today's APOD. (The star looks blue in the infrared picture above, where it is seen near center right.) The star appears to have "broken free" of a dense dust cocoon, and now it has two bright-rimmed "walls" to its left and right. Since this is a yellow K-type star, it should not be able to sculpt and light up "walls" like this. But the infrared picture reveals a pink dot, a baby star, being born in a rounded protrusion of the left "wall". Suddenly this "wall" doesn't look like a wall but like a very shallow little brother or sister of the Cone Nebula itself, since the Cone Nebula also has star formation in its tip. And the shallow "mini-Cone" clearly isn't shaped by the yellow star next to it but by energetic sources in various parts of this region. A larger version of this infrared picture can be found here.

As to what has sculpted these structures, perhaps the answer is that the combined strong ultraviolet emission from many sources in this area contributes to the various shapes and "elephant trunks".
APOD Robot wrote:
The red glow that encompasses the whole region results not only from dust reflection but also emission from hydrogen gas ionized by starlight.
The red glow has nothing to do with dust reflection of starlight. The reddest reflection nebula in the sky is the Antares nebula, which isn't red but yellow. Antares is a superbright star, many times brighter in visual light than any source in the Cone Nebula and S Mon region. Also Antares emits copious amounts of red light, whereas the dominant sources in the Cone and S Mon region are blue. Red light isn't easily reflected in the first place, and if Antares can't produce a truly red reflection nebula, nothing in the Cone and S Mon region can do so. All the red nebulosity here is made by emission caused by ultraviolet light from hot blue stars and other energetic sources.

Ann
Last edited by Ann on Tue Aug 06, 2013 9:54 am, edited 1 time in total.
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Boomer12k » Tue Aug 06, 2013 6:46 am

Also, The Christmas Tree Cluster, or Nebula. Since, as Ann points out, there is star formation going on inside, it is a "Pillar of Creation"...like The Eagle Nebula...a dense Molecular Cloud. A "Finger" sticking itself into the Emission Nebula. Maybe someone is trying to see....if the nebula is...."done".... :shock:

Always a wonderful, and wondrous sight... :D

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Indigo_Sunrise » Tue Aug 06, 2013 10:40 am

Great APOD, but......
Strange shapes and textures can be found in THE neighborhood of the Cone Nebula.

:fixed:


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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by zbvhs » Tue Aug 06, 2013 10:51 am

The Cone Nebula looks rather like the wake produced by a blunt body tearing through a tenuous gas at hypersonic speed.
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by orin stepanek » Tue Aug 06, 2013 11:36 am

I like 8-) 8-) :wink: :D :thumb_up: :thumb_up: :yes: :yes:
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by neufer » Tue Aug 06, 2013 11:44 am

Click to play embedded YouTube video.
Click to play embedded YouTube video.
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by supamario » Tue Aug 06, 2013 11:53 am

Beyond wrote:Ah, the cone nebula. I'll have a two scoop strawberry cone, please. And a bone for the "a mystery" link.
Here's a bone:
http://adsabs.harvard.edu/full/1989MNRAS.237..995S

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Beyond » Tue Aug 06, 2013 12:49 pm

supamario wrote:
Beyond wrote:Ah, the cone nebula. I'll have a two scoop strawberry cone, please. And a bone for the "a mystery" link.
Here's a bone:
http://adsabs.harvard.edu/full/1989MNRAS.237..995S
Image just doesn't seem to have the right kind of teeth to chew "the bone" you provided. :lol2:
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by BDanielMayfield » Tue Aug 06, 2013 2:40 pm

zbvhs wrote:The Cone Nebula looks rather like the wake produced by a blunt body tearing through a tenuous gas at hypersonic speed.
Yes Vergil, it does look like a wake, and in a way I think that it is, only instead of the head of the cone tearing through the gas it’s the gassious stellar winds that are blasting past a young solar system. I imagine that the round head is the region where the stellar wind from inside the “conehead” piles up against the winds coming out from the main part of the star cluster.
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Psnarf » Tue Aug 06, 2013 2:58 pm

[Somehow I knew there'd be a reference to the Coneheads in here.]
Just wondering about the density of the dust. From 2500 light years, it appears to be very dense, but you can probably drive a spaceship through there without hitting a single particle. Is the subject is answered in the FAQ, tutorials or lectures?

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Chris Peterson » Tue Aug 06, 2013 3:09 pm

Ann wrote:The colors are not only wonderfully beautiful but also "true", so that we would see them just this way if the sensitivity of our eyes was enormously enhanced. (Of course, if our eyes were this sensitive, we couldn't spot the colors of the nebulosity at the same time as we looked at the stars, for the same reason that we can't look at the solar corona unless the blinding light of the disk of the Sun is blocked by, say, the disk of the Moon.)
Our eyes could simultaneously be sensitive enough to detect nebulosity, and still see detail on the surface of the Sun. Sensitivity simply defines the lower limit of detection. Dynamic range defines the difference between the brightest and dimmest thing that can be seen (without saturation).

I mention this because my first thought on viewing today's image was how it shows the limitations of our very best imaging technology. As good as cameras have become, they simply lack the dynamic range to properly capture a scene like this. As a result, there are many stars which appear bloated with saturated cores. It is possible to extend dynamic range by stacking shorter exposures that aren't blown out, but only at the expense of increasing noise in the much dimmer nebular areas. What is needed is a sensor that can count a lot more photons in each pixel, but we don't yet have one.
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by neufer » Tue Aug 06, 2013 4:02 pm

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by BDanielMayfield » Tue Aug 06, 2013 4:29 pm

Chris Peterson wrote:
Ann wrote:The colors are not only wonderfully beautiful but also "true", so that we would see them just this way if the sensitivity of our eyes was enormously enhanced. (Of course, if our eyes were this sensitive, we couldn't spot the colors of the nebulosity at the same time as we looked at the stars, for the same reason that we can't look at the solar corona unless the blinding light of the disk of the Sun is blocked by, say, the disk of the Moon.)
Our eyes could simultaneously be sensitive enough to detect nebulosity, and still see detail on the surface of the Sun. Sensitivity simply defines the lower limit of detection. Dynamic range defines the difference between the brightest and dimmest thing that can be seen (without saturation).

I mention this because my first thought on viewing today's image was how it shows the limitations of our very best imaging technology. As good as cameras have become, they simply lack the dynamic range to properly capture a scene like this. As a result, there are many stars which appear bloated with saturated cores. It is possible to extend dynamic range by stacking shorter exposures that aren't blown out, but only at the expense of increasing noise in the much dimmer nebular areas. What is needed is a sensor that can count a lot more photons in each pixel, but we don't yet have one.
I find this fascinating, since telescopes and how they work have been of interest to me for many years. So, if I'm following you correctly Chris, the limiting factor isn't the optics, but it's the data storage capacity per pixel? What is the max photon count of today's data collectors?
Just as zero is not equal to infinity, everything coming from nothing is illogical.

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Chris Peterson » Tue Aug 06, 2013 5:35 pm

BDanielMayfield wrote:I find this fascinating, since telescopes and how they work have been of interest to me for many years. So, if I'm following you correctly Chris, the limiting factor isn't the optics, but it's the data storage capacity per pixel? What is the max photon count of today's data collectors?
All professional cameras use CCD sensors, except for some special applications. Most amateurs astroimagers also use cameras with CCD sensors, although CMOS technology is improving, and such sensors are sometimes used by amateurs (especially those imaging with DSLRs). I'll talk about CCDs here, although there are many parallels with the way CMOS detectors work.

Each pixel occupies an area of silicon (and a volume as well, although generally the area is the important parameter). When a photon hits the top surface of the pixel, it produces an electron, which is stored in the volume of that pixel as a charge. The number of electrons that can be stored depends on the volume of silicon available (and since the pixel is fairly planar, that really means the area). So as a rule, the bigger the pixel the better, and professional cameras often have very large pixels (20-50 um is common for some cameras; amateur cameras usually have 5-10 um pixels).

Good sensors can store 100,000 or more electrons per pixel. But when the camera is read, there is some noise introduced, typically on the order of 10 electrons. So the true dynamic range might be around 1:10,000. Signal below 10 electrons is buried in noise, signal over 100,000 electrons is saturated (clipped). This dynamic range can be represented digitally by 13-14 bits.

An emission nebula might contain stars with an apparent magnitude of 4, and the faintest nebulosity will be close to the sky background, mag 22 or so. That's a dynamic range of around 1:15 million (about 24 bits). So there is a huge difference between the dynamic range of our best cameras and the actual dynamic range of the regions we image.

There are tricks that can be used. When the intent is largely aesthetic, images can be collected at several different exposure times and then combined with clever masking. Images can also be collected with short exposures and then added together. The signal adds linearly, and noise quadratically, so the S/N increases... but not as fast as we'd like. The real problem is the previously mentioned readout noise, which just keeps piling up with each subimage. So we'd like lots of short images to reduce overexposure, but one single long image to get the lowest readout noise.

Terrestrial photographers might recognize a similarity between the above mentioned stacking of subexposures and the technique called high dynamic range imaging (HDR) which works the same way, combining images with different exposures to create an image with more dynamic range than the camera sensor is intrinsically capable of delivering.

BTW, the bloating of stars is mostly an optical issue. Diffraction makes all the stars appear to have a finite diameter, rather than being true point sources. The brighter the star, the farther out along that diffracted diameter we can see. Some bloating may also be caused by internal reflections in elements before the sensor, and also by scattering in the sensor itself.
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by stephen63 » Tue Aug 06, 2013 5:38 pm

This sensor has the greatest Full Well Capacity in the FLI line of cameras. 650,000 e- is a LOT!
PL4301 Sensor Specs
Sensor: Truesense KAF-4301E
Pixels: 2084 x 2084
Pixel Size: 24 μm
Full Well Capacity: 650,000 e-
Sensor Diagonal: 70.7 mm
Video Size (inch): 4.3
Anti Blooming: None
Color Options: Monochrome
CCD Type: Front Illuminated
CCD Grades: 1, 2
The company e2v made the WFC3 sensor used on the Hubble Space Telescope. I couldn't find the specs.
My QSI-583 has a whopping 25,500 e-!

I may have made a mistake. The e2v site claims the chip, but a different corp, Ball Aerospece claims the camera.
Last edited by stephen63 on Tue Aug 06, 2013 5:57 pm, edited 1 time in total.

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Chris Peterson » Tue Aug 06, 2013 5:56 pm

stephen63 wrote:This sensor has the greatest Full Well Capacity in the FLI line of cameras. 650,000 e- is a LOT!
PL4301 Sensor Specs
Sensor: Truesense KAF-4301E
Pixels: 2084 x 2084
Pixel Size: 24 μm
Full Well Capacity: 650,000 e-
The KAF-4301 is a very nice sensor for astroimaging. Not shown above is its moderately high readout noise of 15 electrons. That means its actual dynamic range is 1:43,000, or 15.4 bits. Very good indeed, but still only 11.7 magnitudes.

The sensor achieves its large well depth primarily through a large surface area. This could be a problem for amateur imagers, with their typically fairly small telescopes. For a seeing limited image in a good location, you'd like a single pixel to subtend around one-half arcsecond. That requires a telescope with a 10-meter focal length (more than half that of the Keck scopes!) Amateur telescopes tend to have focal lengths in the 0.5-3 meter range. So for most, using a sensor with such large pixels would result in an undersampled image- one that can't capture the full resolution available given the optics and sky conditions.
Chris

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by robgendler » Tue Aug 06, 2013 7:20 pm

"I mention this because my first thought on viewing today's image was how it shows the limitations of our very best imaging technology. As good as cameras have become, they simply lack the dynamic range to properly capture a scene like this. As a result, there are many stars which appear bloated with saturated cores. It is possible to extend dynamic range by stacking shorter exposures that aren't blown out, but only at the expense of increasing noise in the much dimmer nebular areas. What is needed is a sensor that can count a lot more photons in each pixel, but we don't yet have one."

Chris...well as soon as I saw your comment above I realized that you have no idea how the image was made. It obvious was not a single exposure. The image was assembled in a piecemeal manner. The color came from a two frame mosaic of DSS data, further enhanced with dark sky image data of my own. The luminance was a 140 panel mosaic of narrowband data from the Subaru archive which was then layered onto a synthetic luminance from the DSS data. The native size of this image exceeded 2.5 GB....requiring the final version to be downsized to just under one GB because of computer resources. Any bloating of the stellar cores was simply a result of nonlinear processing....which was required to display the immense dynamic range of this field. A single shot image of this field with this level of detail is simply impossible with today's telescopes and camera technology. A composite of this nature and quality had to be assembled in a piecemeal approach......... I'm sorry that was your first thought upon viewing the image.

BTW I think there are some good exchanges of information on this forum which are educational. On the other hand some members see someone's dedication and hard work as an opportunity to compete for who can post the wittiest response. I have a sense of humor too but you'll never see this on dedicated CCD forums because those folks understand what goes into an image like this and they are always respectful.

For those interested below are two links, the first a higher res version (4500 X 2540), the second link is a labeled version.

http://www.robgendlerastropics.com/Cone ... SS-LL.html

http://www.robgendlerastropics.com/Cone ... Label.html

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by Chris Peterson » Tue Aug 06, 2013 7:39 pm

robgendler wrote:Chris...well as soon as I saw your comment above I realized that you have no idea how the image was made.
Thanks for providing that information!
Any bloating of the stellar cores was simply a result of nonlinear processing....which was required to display the immense dynamic range of this field. A single shot image of this field with this level of detail is simply impossible with today's telescopes and camera technology.
My point, exactly. In fact, realistically, even a multiple image shot of a field like this is effectively impossible with today's camera technology if the goal is to capture the full dynamic range.
BTW I think there are some good exchanges of information on this forum which are educational. On the other hand some members see someone's dedication and hard work as an opportunity to compete for who can post the wittiest response. I have a sense of humor too but you'll never see this on dedicated CCD forums because those folks understand what goes into an image like this and they are always respectful.
I fear that you misunderstood my comment as a criticism. It was no such thing... the image is fantastic. I was simply distinguishing between sensitivity and dynamic range in Ann's comment, and then discussing the significant limitations that current sensor technology place on recording high dynamic range objects like this, with many orders of magnitude between the actual and instrumental dynamic ranges.
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by geckzilla » Tue Aug 06, 2013 8:10 pm

Just once, Rob, I'd like you to come to the forum without sounding like... well, a jerk. :(
robgendler wrote:BTW I think there are some good exchanges of information on this forum which are educational. On the other hand some members see someone's dedication and hard work as an opportunity to compete for who can post the wittiest response. I have a sense of humor too but you'll never see this on dedicated CCD forums because those folks understand what goes into an image like this and they are always respectful.
I think you are misunderstanding the people at this forum. Yes, it's true that most people have only the faintest idea of what's going on for these images because they've never done it before. And yes, there is a fair amount of joking and especially puns going around, but that doesn't mean that people are being disrespectful. Being disrespectful isn't allowed and it doesn't matter who you are--you're gonna get pinged by a moderator if you keep it up. There's always jerks in the world and I do my best to either correct them and maybe I get frustrated or am wrong at times myself but we are doing our best to run this forum as a friendly and informational place.
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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by robgendler » Tue Aug 06, 2013 9:25 pm

Some people contribute by asking questions....some contribute by trying to answer them....others just want an audience to applaud their wit it seems. I hope it makes you feel better to label me a jerk. Maybe as an effective moderator (is that your job?) you could handle constructive criticism and not immediately attack the messenger.

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Re: APOD: In the Vicinity of the Cone Nebula (2013 Aug 06)

Post by geckzilla » Tue Aug 06, 2013 10:29 pm

Yes, your post made me feel uncomfortable, and no it doesn't make me feel better to have to confront you (in fact it made me more uncomfortable). It was an observation intended to criticize you back. I want to think that you are a nice guy and someone who I can look to for inspiration but every time you make a post, it seems to be an irritated response to something. You seem to look down on us. Also, I can't send you a private message on the matter which is what I would have preferred because you only use a guest account to post.
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