APOD: The Pleiades Deep and Dusty (2017 Nov 14)

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APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby APOD Robot » Tue Nov 14, 2017 5:05 am

Image The Pleiades Deep and Dusty

Explanation: The well-known Pleiades star cluster is slowly destroying part of a passing cloud of gas and dust. The Pleiades is the brightest open cluster of stars on Earth's sky and can be seen from almost any northerly location with the unaided eye. The passing young dust cloud is thought to be part of Gould's Belt, an unusual ring of young star formation surrounding the Sun in the local Milky Way Galaxy. Over the past 100,000 years, part of Gould's Belt is by chance moving right through the older Pleiades and is causing a strong reaction between stars and dust. Pressure from the stars' light significantly repels the dust in the surrounding blue reflection nebula, with smaller dust particles being repelled more strongly. A short-term result is that parts of the dust cloud have become filamentary and stratified. The featured deep image also captured Comet C/2015 ER61 (PanSTARRS) on the lower left.

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Ann » Tue Nov 14, 2017 5:44 am

Wow, that's a truly fascinating picture! :D

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Boomer12k » Tue Nov 14, 2017 8:36 am

The "BLUE"...looks like a person....sitting in the LOTUS....maybe they are doing a Cosmic Meditation.... "Ooooooommmmmmmm"......

Truly Awesome.
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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Cassiopea » Tue Nov 14, 2017 9:53 am

That is bloody awful... :cry:

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby NCTom » Tue Nov 14, 2017 12:10 pm

Follow up reading introduced me to more info on Gould's Belt and Smith's Cloud. The fireworks of these collisions must be awesome, if of course you have a few million years to hang around and watch it develop.

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby rstevenson » Tue Nov 14, 2017 2:04 pm

What are we supposed to make of the fine white speckles all over this picture? Surely they are processing artifacts. If so, they destroy any utility the picture may have; if not, what are they?

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby neufer » Tue Nov 14, 2017 2:21 pm

https://en.wikipedia.org/wiki/Benjamin_Apthorp_Gould wrote:
<<Benjamin Apthorp Gould (September 27, 1824 – November 26, 1896) was a pioneering American astronomer. His measurements of L. M. Rutherfurd's photographs of the Pleiades in 1866 entitle him to rank as a pioneer in the use of the camera as an instrument of precision. Astronomers continue to investigate the astrophysics of a large scale feature of the Milky Way to which he called their attention in 1877, and honor him with its name, The Gould Belt. A crater on the Moon is named after him.

After going on to Harvard College and graduating in 1844, he studied mathematics and astronomy under C. F. Gauss at Göttingen, Germany, during which time he published approximately 20 papers on the observation and motion of comets and asteroids. Following completion of his Ph.D. (he was the first American to receive this degree in astronomy) he toured European observatories asking for advice on what could be done to further astronomy as a professional science in the U.S.A. The main advice he received was to start a professional journal modeled after what was then the world's leading astronomical publication, the Astronomische Nachrichten.

Gould returned to America in 1848 and from 1852 to 1867 was in charge of the longitude department of the United States Coast Survey. He developed and organized the service, was one of the first to determine longitudes by telegraphic means, and employed the Atlantic cable in 1866 to establish accurate longitude-relations between Europe and America.

After his return to Cambridge, Massachusetts, Gould started the Astronomical Journal in 1849, which he published until 1861. He resumed publication in 1885 and it is still published today. From 1855 to 1859 he acted as director of the Dudley Observatory at Albany, New York, and in 1859 published a discussion of the places and proper motions of circumpolar stars to be used as standards by the United States Coast Survey. In 1861 he undertook the enormous task of preparing for publication the records of astronomical observations made at the U.S. Naval Observatory since 1850.

In 1851 Gould suggested numbering asteroids in their order of discovery, and placing this number in a disk (circle) as the generic symbol of an asteroid.

Appointed in 1862 actuary to the United States Sanitary Commission, he issued in 1869 an important volume of Military and Anthropological Statistics. In 1864 he fitted up a private observatory at Cambridge, Massachusetts, and undertook in 1868, on behalf of the Argentine republic, to organize a national observatory at Córdoba. In 1871 he became the first director of the Argentine National Observatory. While there, he and four assistants extensively mapped the southern hemisphere skies using newly developed photometric methods. On June 1, 1884, he made the last definite sighting of the Great Comet of 1882. The need of astronomers for good weather prediction spurred Gould to collaborate with Argentine colleagues to develop the Argentine National Weather Service, the first in South America.

In 1874 Gould completed his greatest work, the Uranometria Argentina (published 1879), for which he received in 1883 the gold medal of the Royal Astronomical Society. The publication assigned Gould designations to all bright stars within 100 degrees of the south celestial pole in a manner similar to what Flamsteed had earlier done for the northern hemisphere. Gould followed his Uranometria Argentina with a zone-catalogue of 73,160 stars (1884), and a general catalogue (1885) compiled from meridian observations of 32,448 stars.>>
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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Chris Peterson » Tue Nov 14, 2017 2:40 pm

rstevenson wrote:What are we supposed to make of the fine white speckles all over this picture? Surely they are processing artifacts. If so, they destroy any utility the picture may have; if not, what are they?

I would say that they are noise, not processing artifacts. Noise does not destroy the utility of an image, it merely sets the lower bound on the ability to extract information. And noise is generally seen as aesthetically damaging when aesthetics are the intent.

This image does not appear to have aesthetic intent; rather, the contrast has been pushed right down into the noise in an effort to make the most subtle of structure as visible as possible.
Chris

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby rstevenson » Tue Nov 14, 2017 2:49 pm

So... the contrast has been pushed (processed) so far that the noise is highly visible, in order to get a clearer view of the filaments of gas and dust. Fair enough.

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Fred the Cat » Tue Nov 14, 2017 3:19 pm

Those stratified cats rock! But what are they starring at :?: Maybe cats can see dark matter blobs. :wink: Speaking catmatically, that photo is a miracle of “catification” while today’s APOD seems to paparazzi the Pleiades. :|
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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Roger Venable » Tue Nov 14, 2017 3:21 pm

Interestingly, one can see in the picture the path of the cluster as it moves through the cloud, coming from the top of the frame downward. It cleared the dust from along the path and left a wake of linear condensations in the dust, due to the previous radiation pressure in those locations.

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby BDanielMayfield » Tue Nov 14, 2017 3:38 pm

Is the Sun expected to intersect any dust clouds like this in the foreseeable future? The much stronger stellar winds from the massive B stars in the Pleiades must be able to clear and carve a path though the dust much more effectively than a G star like the Sun could. If Sol passed deeply into such a dust cloud would our view toward the core of our galaxy and outside our galaxy be greatly obscured?

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Chris Peterson » Tue Nov 14, 2017 3:44 pm

BDanielMayfield wrote:Is the Sun expected to intersect any dust clouds like this in the foreseeable future? The much stronger stellar winds from the massive B stars in the Pleiades must be able to clear and carve a path though the dust much more effectively than a G star like the Sun could. If Sol passed deeply into such a dust cloud would our view toward the core of our galaxy and outside our galaxy be greatly obscured?

We're actually passing through one now, albeit less dense than that around the Pleiades.
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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby BDanielMayfield » Tue Nov 14, 2017 3:49 pm

Roger Venable wrote:Interestingly, one can see in the picture the path of the cluster as it moves through the cloud, coming from the top of the frame downward. It cleared the dust from along the path and left a wake of linear condensations in the dust, due to the previous radiation pressure in those locations.

Good observation Roger. I'd guess that a lone star like Sol wouldn't be able to leave much of a notable trail (too small to be seen at this distance) at all.

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby BDanielMayfield » Tue Nov 14, 2017 3:53 pm

Chris Peterson wrote:
BDanielMayfield wrote:Is the Sun expected to intersect any dust clouds like this in the foreseeable future? The much stronger stellar winds from the massive B stars in the Pleiades must be able to clear and carve a path though the dust much more effectively than a G star like the Sun could. If Sol passed deeply into such a dust cloud would our view toward the core of our galaxy and outside our galaxy be greatly obscured?

We're actually passing through one now, albeit less dense than that around the Pleiades.

Interesting Chris. How much less dense would you say? Also, how wide is the path cleared by our Sun's solar winds?

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Chris Peterson » Tue Nov 14, 2017 4:15 pm

BDanielMayfield wrote:
Chris Peterson wrote:
BDanielMayfield wrote:Is the Sun expected to intersect any dust clouds like this in the foreseeable future? The much stronger stellar winds from the massive B stars in the Pleiades must be able to clear and carve a path though the dust much more effectively than a G star like the Sun could. If Sol passed deeply into such a dust cloud would our view toward the core of our galaxy and outside our galaxy be greatly obscured?

We're actually passing through one now, albeit less dense than that around the Pleiades.

Interesting Chris. How much less dense would you say? Also, how wide is the path cleared by our Sun's solar winds?

Well, it's sort of an odd situation we're in. The interstellar medium (ISM) in the region around the Sun, with a size of a few hundred light years, is impoverished (by about an order of magnitude) compared with the average density of the ISM in the Milky Way. We're basically in a large bubble. But inside that bubble, we're currently in a denser cloud, which gets our local region almost (but not quite) back up to the average ISM density. The cloud we're passing through has a density of about 0.3 atoms/cm3. The cloud around the Pleiades is probably several orders of magnitude denser, and has different optical properties given that it consists of dust (large particles) as opposed to the ionized gas around us.
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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby bystander » Tue Nov 14, 2017 5:05 pm

Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Jim Armstrong » Tue Nov 14, 2017 5:20 pm

Curious if "on" the Earth's sky means something different than "in."

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby BDanielMayfield » Tue Nov 14, 2017 5:45 pm

Jim Armstrong wrote:Curious if "on" the Earth's sky means something different than "in."

In the sky, things in the atmosphere like birds and airplanes.

On the sky, things on the celestial sphere.
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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby ta152h0 » Tue Nov 14, 2017 8:52 pm

glad we have eyeballs ( and use them )
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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby robgendler@att.net » Wed Nov 15, 2017 2:08 am

Cassiopea wrote:That is bloody awful... :cry:



I agree.....

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Re: APOD: The Pleiades Deep and Dusty (2017 Nov 14)

Postby Andy01 » Wed Nov 15, 2017 5:59 am

Probably the worst APOD I have seen in a loooong time - way overprocessed and pushed beyond the limit.
I applaud what the author has intended to do to reveal the structures & dust, but one cannot simply cut corners and stretch insufficient data beyond all hope in the expectation a decent result.
This needs a LOT more exposure time, lots and lots more exposure time - then a stretch to bring out the best from the data imo.


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