APOD: The Horsehead Nebula (2012 Oct 21)

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APOD: The Horsehead Nebula (2012 Oct 21)

Post by APOD Robot » Sun Oct 21, 2012 4:05 am

Image The Horsehead Nebula

Explanation: One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s. The red glow originates from hydrogen gas predominantly behind the nebula, ionized by the nearby bright star Sigma Orionis. The darkness of the Horsehead is caused mostly by thick dust, although the lower part of the Horsehead's neck casts a shadow to the left. Streams of gas leaving the nebula are funneled by a strong magnetic field. Bright spots in the Horsehead Nebula's base are young stars just in the process of forming. Light takes about 1,500 years to reach us from the Horsehead Nebula. The above image was taken with the 0.9-meter telescope at Kitt Peak National Observatory.

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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by Ann » Sun Oct 21, 2012 4:29 am

A golden oldie! :D The photo is almost 18 years old. Of course, the Horsehead Nebula itself is much older, but it never gets old! :D
APOD Robot wrote:
One of the most identifiable nebulae in the sky, the Horsehead Nebula in Orion, is part of a large, dark, molecular cloud. Also known as Barnard 33, the unusual shape was first discovered on a photographic plate in the late 1800s.
It was discovered on a photographic plate in the late 1800s? Guess what that means? The photographic plates of the 1800s were all blue-sensitive. So the photographic plates discovered the dark horsehead shape against a blue background!

What blue light is there in the red Ha Horsehead backgound? Well, the dominant red light behind the Horsehead is, of course, hydrogen alpha emission. But the blue or blue-green light that the old photographic plates discovered is hydrogen beta emission! This picture shows you the emission lines of hydrogen, the Balmer series. Hydrogen alpha is specifically pointed out. The blue-green line to the left of hydrogen alpha is hydrogen beta.

Imagine that those who first discovered the Horsehead Nebula must have thought of it as a dark shape against a blue background! Today everybody thinks of it as a horsehead shape against a red background. Yet nobody has ever seen the red color of the red background of the Horsehead Nebula "in real life"! In fact, your best chance of ever seeing the Horsehead Nebula through a telescope is to observe it through a hydrogen beta filter that blocks all almost light from the background of the Horsehead Nebula and only lets through the blue-green light of hydrogen beta!

Then you, too, will see the Horsehead Nebula in the same way as the old photographic plates did: as a dark shape against a lighter "sky", which is lit by blue light!

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AlexG

Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by AlexG » Sun Oct 21, 2012 6:17 am

Why don't smaller stars have spikes on the photo? Sorry if the question is stupid.

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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by orin stepanek » Sun Oct 21, 2012 11:09 am

This one should be for emc; lol 8-) :wink: :D
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by neufer » Sun Oct 21, 2012 12:46 pm

AlexG wrote:
Why don't smaller stars have spikes on the photo?
They do have spikes; it's just that they are too faint to observe.

(They also have extended haloes which are too faint to observe.)
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by Boomer12k » Sun Oct 21, 2012 1:43 pm

Maybe we should call it ...." The SMILING Horsehead Nebula"....wonder why it is smiling....maybe the star at the bottom is keeping it warm in the cold depths of space.....hmmmmm.....


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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by skywatcher88 » Sun Oct 21, 2012 2:33 pm

Any one see a roaring lions head instead of a poor representation of the head of a horse?Turn the pic 45 degrees to the left and there is the roaring lion !
Just a difference in perspective.
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by neufer » Sun Oct 21, 2012 2:57 pm

Image
Boomer12k wrote:
Maybe we should call it ...." The SMILING Horsehead Nebula"....wonder why it is smiling....maybe the star at the bottom is keeping it warm in the cold depths of space.....hmmmmm.....


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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by Moonlady » Sun Oct 21, 2012 3:02 pm

Ah timeless beauty...looks like a sea horse too!

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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by ta152h0 » Sun Oct 21, 2012 7:37 pm

my first target on the night of Dec 24, 1963 in Ann Arbor, Michigan with my brand new SS Kresge telecope I just got for Christmas.
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by emc » Mon Oct 22, 2012 1:09 pm

I love it here! The stable is full of hey!

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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by DavidLeodis » Mon Oct 22, 2012 1:16 pm

The Horsehead Nebula looks huge (which it probably is) in such images as the APOD, but it seems quite tiny (relatively speaking) in the wider field APOD image that is brought up through the 'Horsehead Nebula' link in the penultimate sentence. Without its presence being noted in that APOD I bet many (if not most) of us would never have realised it is in that image! :)

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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by neufer » Mon Oct 22, 2012 1:24 pm

emc wrote:
I love it here! The stable is full of hey!
Click to play embedded YouTube video.
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by Wbill » Mon Oct 22, 2012 1:35 pm

Has the nebula changes since the first pictures were taken?

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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by emc » Mon Oct 22, 2012 2:20 pm

neufer wrote:
emc wrote:
I love it here! The stable is full of hey!
Click to play embedded YouTube video.
Image

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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by emc » Mon Oct 22, 2012 2:44 pm

Wbill wrote:Has the nebula changes since the first pictures were taken?
Yes. There are streams of gas emanating from nebula… so it is evolving.
Probably too much "hay"

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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by neufer » Mon Oct 22, 2012 3:07 pm

emc wrote:
Image
Wbill wrote:
Has the nebula changes since the first pictures were taken?
Yes. There are streams of gas emanating from nebula… so it is evolving.
http://www.seinfeldscripts.com/TheRye.htm wrote:
GEORGE: What the hell happened?

KRAMER: The horse is gassy. Must have been the Beef-A-Reeno.

GEORGE: Beef-A-Reeno? You fed the horse Beef-A-Reeno?!

KRAMER: Well, I overbought!
http://freescruz.com/~4cygni/horsehead/B33-19thC_4.htm wrote:

The Horsehead Project:
19th Century Study of Bright and Dark Nebulae
Stephen R. Waldee (c) 1990-2012

<<Mrs. Williamina Paton Fleming (1857-1911) came to Massachusetts from her native Scotland in 1878 and went to work early the following year in the household of Dr. Edward C. Pickering -- as his second maid! Impressed with her accuracy and persistence, Director Pickering hired Mrs. Fleming to work part-time at the Observatory in 1879, and from 1881 until the year of her death she was a staff member, a very good example of one of the early unsung women the male-dominated world of astronomy.

Beginning on June 27, 1888, Mrs. Fleming took each of the Orion plates, placed it on an illuminated frame at an angle of 45 degrees, and studied all portions with a magnifying glass to find any suspected nebulae recorded during the exposure. Each object's coordinates were measured, referred to the star chart of the standard Bonner Durchmusterung reference published in 1863, plotted at the same scale as the new Harvard photographs. In the HCO Annals publication a table is given comparing the results of searching through four plates, covering the area, with a fifth plate used to check the results of the others. The "A" rating given to the Zeta Orionis nebula qualified as 'unmistakable' on all the plates taken of the region.

The official discovery plate that registered the Horsehead nebula was number B2312, taken with the Bache telescope in Cambridge on February 6, 1888, with an exposure time of 90 minutes. The HCO logbooks are now online (2012); the cover for Series B is seen here, with the individual pages for the dates February 3 and 6, 1888, visible here; the entry for 2312 is very brief, indicating the area (in right ascension) covered by the plate, and that the sidereal clock rate was employed. By setting up the star chart program 'TheSky' Version 6 for the coordinates of Cambridge and the date of that exposure, the author determined that the star Alnitak, and the nebulae in close proximity, would have transited not long past midnight.

HCO director E. C. Pickering reported the results of the examination and measurements made on this plate by 'Mrs. M. Fleming' (using initial "M" for his preferred diminutive "Mina") in his 1890 paper "Detection of New Nebulae by Photography"; here (below) he describes the careful method of Williamina Fleming in her examination of the negatives to make discoveries of new objects therein:
On B2312, Mrs. Fleming recorded a nebulosity -- listed as No. 21 in her table -- described as follows (bold emphasis added by the present author, to signify the Horsehead's dark cloud): "A large nebulosity extending nearly south from Zeta Orionis for about 60 minutes. More intense and well marked on the following side, with a semicircular indentation 5 minutes in diameter 30 minutes south of Zeta. Good plates of this region show this object, and it has been used here as a test for some time..."

In referring to "this object", it is evident that Pickering means the large 60-minute nebula and not specifically the "semicircular indentation".

The "large nebula" extending south of Zeta was reported by Edward Pickering to Dr. Dreyer for inclusion in his successor to the NGC, the Index Catalogue of 1895; Dreyer's list was ordered by right ascension and thus the object was numerated "IC-434" in the Dreyer's (first) Index Catalogue. The Horsehead nebula, of course, is the "semicircular indentation 5 minutes in diameter" and, as it was described by Mrs. Fleming in Pickering's paper as a detail of nebula no. 434, it was not cited as a separate object at that time, and not included in the IC (indeed, it was not given a 'catalogue number' specifically until Edward Barnard cited it in his 1919 published list of dark markings (no. 33, on the page shown here.)

The British astronomer and compiler "references" Harvard's new nebulae to "Pickering" on the second introductory page, and again, in the individual nebula entries, to HCO's director--not as Pickering had specifically stipulated, to Fleming. Numerous articles consulted by this paper's author, analyzing historic contributions to astronomy by women, have reported what is obviously a consensus view: that it was formerly conventional practice to diminish 'underlings' and attribute their work to their ultimate superiors. Furthermore, women were at a special disadvantage in this era of science: as researcher Steven H. Yaskell observes in his 2005 article "Henrietta Swann Leavitt, the star catcher", included on this web page:

...women did more than replace the largely young male "computers" who performed the routine computations for the daily observations and measurements (and who suffered similar career dead-ends like their female counterparts, and in some cases worse). Some in England became full partners with the hired male staff... The same was true for the woman computers at the Harvard College Observatory. But any sense of a shared social status was missing. Some archives and the inevitable anecdotes suggest that it was very much a "child - to - father" relationship between the women computers and the regular male staff, and particularly, with the director.

However, all analysis of Edward Pickering's attitude and behavior to his 'female underlings' shows that he stood apart from the male- authority- figure- dominated attitudes of his time. In the words of Dr. Gina Hamilton, (University of Southern Maine), "While Pickering published in his own name, he freely gave credit to his researchers...Among the many famous women who worked with Pickering at Harvard were Williamina Fleming (c 1881), who began work on an empirical classification system of spectral types in stars. While engaged in this monumental task, she discovered ten novae, more than three hundred variable stars, and some sixty new nebulae...Fleming's classification system was further refined by Annie Jump Cannon."

A further accounting of Nebulae discovered at the Harvard College Observatory by E. C. Pickering (HCO Annals, Volume 60, 1908) confirms the progressive and collegial attitude of the Observatory's Director. In the table on p. 149 -- online here -- entry No. 62 lists nebula 434 as having been discovered by "W. P. Fleming". We have truncated items 19 through 55 in order to show the relevant section of the page, below:

So, as far as the Harvard College Observatory is concerned, the official discoverer of the nebulosity containing the Horsehead was a woman, and one who been promoted from housemaid to observatory staff member!
>>
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by Beyond » Mon Oct 22, 2012 3:30 pm

So Connie Hines is not the only "Star" to 'rub shoulders' with the Famous Mr. ED. It's just that the others got lost in the 'attitude' dust of yesteryear.
This thread seems to be a pretty good 'post'ing for both Mr. ED's. :lol:
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by Chris Peterson » Mon Oct 22, 2012 3:55 pm

Wbill wrote:Has the nebula changes since the first pictures were taken?
All nebulas change continuously. However, I don't believe that the Horsehead has changed enough for that change to be detectable between the oldest and newest images we have available. Nebulas with significant detectable changes tend to be the much more energetic products of novas and supernovas, not dust clouds.
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by orin stepanek » Mon Oct 22, 2012 4:48 pm

Beyond wrote:So Connie Hines is not the only "Star" to 'rub shoulders' with the Famous Mr. ED. It's just that the others got lost in the 'attitude' dust of yesteryear.
This thread seems to be a pretty good 'post'ing for both Mr. ED's. :lol:
Click to play embedded YouTube video.
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by ta152h0 » Mon Oct 22, 2012 4:56 pm

Perhaps Eta Carinae is energetic enough ? And by the way, when was the first photograph of stuff in space taken and who was the historic object ?
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Re: APOD: The Horsehead Nebula (2012 Oct 21)

Post by Anthony Barreiro » Mon Oct 22, 2012 5:58 pm

ta152h0 wrote:Perhaps Eta Carinae is energetic enough ? And by the way, when was the first photograph of stuff in space taken and who was the historic object ?
From the wikipedia article on astrophotography:

<< The first known attempt at astronomical photography was by Louis Jacques Mandé Daguerre, inventor of the daguerreotype process which bears his name, who attempted in 1839 to photograph the moon. Tracking errors in guiding the telescope during the long exposure meant the photograph came out as an indistinct fuzzy spot. John William Draper, an American physician, chemist and scientific experimenter, managed to make the first successful photograph of the moon a year later on March 23, 1840, taking a 20-minute-long daguerreotype image using a 5-inch (13 cm) reflecting telescope. >>

This makes sense. The first object most people observe through a telescope is the Moon. It's big and bright.
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MPG: Cosmic Refinery

Post by bystander » Fri Nov 23, 2012 6:49 pm

Cosmic Refinery
Max Planck Gesellschaft | 2012 Nov 23
Using IRAM's 30m-telescope, astronomers find indications for vast petroleum reservoirs in the Horsehead Nebula
Image
The distinct Horsehead Nebula in Orion is not
only a favorite object of astrophotographers, but
apparently also a cosmic petroleum refinery. ©ESO

What sounds like science fiction is actually reality: using the 30m-telescope of the Institute for Radio Astronomy for astronomical observations in the millimetre range of wavelengths, astronomers have detected, for the first time, the interstellar molecule C3H+, in our galaxy. It belongs to the hydrocarbon family and is thus part of major energy resources of our planet, i.e. petroleum and natural gas. The discovery of this molecule at the heart of the famous Horsehead Nebula in the Constellation of Orion also confirms that this region is an active cosmic refinery.

The Horsehead Nebula, 1,300 light-years from Earth, is located in the Orion constellation, which will become more and more visible in the night skies over the next few weeks. Due to its famous and easily-recognizable shapes which gave the Nebula its name, is one of the most photographed objects by astronomers. But the Horsehead Nebula is also a fantastic interstellar chemistry lab, where high density gas and intense stellar light continuously interact and trigger many-layered chemical reactions.

Using the 30m-radiotelescope near the Pico del Veleta in the Spanish Sierra Nevada, IRAM-astronomers Jérôme Pety and his team for the first time undertook a systematic survey of the chemical content of the Horsehead's mane. The international project, called "Whisper", would not have been possible without the recent technical upgrades of the telescope instruments. "Earlier, such a comprehensive enterprise would have taken at least one year of observations. Now we could complete measurements after one week", says Arnaud Belloche at the Max Planck Institute for Radio Astronomy. This opens new possibilities to classify the different kinds of gas in the universe, based on the molecules they contain.

In their current survey, the scientists were able to detect 30 molecules in the region, including many small hydrocarbons, the smallest molecules that compose petroleum and natural gas. The researchers were surprised by the unexpectedly high levels of hydrocarbons. "The nebula contains 200 times more hydrocarbons than the total amount of water on Earth!", said astronomer Viviana Guzman. In addition, one of these small hydrocarbons, the propynylidyne ion (C3H+), was observed for the first time in space as part of this work – even though this positively charged ion is a key player in the chemical reactions which link the small hydrocarbons together.

But how do these hydrocarbons form? In their article, Jérôme Pety and his colleagues propose that they result from the fragmentation of giant carbonaceous molecules named PAHs. These giant molecules could be eroded by ultra-violet light, giving a large amount of small hydrocarbons. This mechanism would be particularly efficient in regions like the Horsehead Nebula where the interstellar gas is directly exposed to the light of a nearby massive star. "We observe the operation of a natural refinery of petroleum of gigantic size", concludes Jérôme Pety.

The IRAM-30m line survey of the Horsehead PDR:
  • I. CF+ as a tracer of C+ and a measure of the Fluorine abundance - Viviana Guzman et al II. First detection of the l-C3H+ hydrocarbon cation - Jérôme Pety et al
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Re: MPG: Cosmic Refinery

Post by neufer » Fri Nov 23, 2012 8:47 pm

bystander wrote:Cosmic Refinery
Max Planck Gesellschaft | 2012 Nov 23
Using the 30m-radiotelescope near the Pico del Veleta in the Spanish Sierra Nevada, IRAM-astronomers Jérôme Pety and his team for the first time undertook a systematic survey of the chemical content of the Horsehead's mane. The international project, called "Whisper", would not have been possible without the recent technical upgrades of the telescope instruments. "Earlier, such a comprehensive enterprise would have taken at least one year of observations. Now we could complete measurements after one week", says Arnaud Belloche at the Max Planck Institute for Radio Astronomy. This opens new possibilities to classify the different kinds of gas in the universe, based on the molecules they contain.

In their current survey, the scientists were able to detect 30 molecules in the region, including many small hydrocarbons, the smallest molecules that compose petroleum and natural gas. The researchers were surprised by the unexpectedly high levels of hydrocarbons. "The nebula contains 200 times more hydrocarbons than the total amount of water on Earth!", said astronomer Viviana Guzman. In addition, one of these small hydrocarbons, the propynylidyne ion (Image)+, was observed for the first time in space as part of this work – even though this positively charged ion is a key player in the chemical reactions which link the small hydrocarbons together.

But how do these hydrocarbons form? In their article, Jérôme Pety and his colleagues propose that they result from the fragmentation of giant carbonaceous molecules named PAHs. These giant molecules could be eroded by ultra-violet light, giving a large amount of small hydrocarbons. This mechanism would be particularly efficient in regions like the Horsehead Nebula where the interstellar gas is directly exposed to the light of a nearby massive star. "We observe the operation of a natural refinery of petroleum of gigantic size", concludes Jérôme Pety.
Art Neuendorffer