Starship Asterisk*

Orion Nebula: The Hubble View

Explanation: Few cosmic vistas excite the imagination like the Orion Nebula. Also known as M42, the nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1,500 light-years away. The Orion Nebula offers one of the best opportunities to study how stars are born partly because it is the nearest large star-forming region, but also because the nebula's energetic stars have blown away obscuring gas and dust clouds that would otherwise block our view - providing an intimate look at a range of ongoing stages of starbirth and evolution. This detailed image of the Orion Nebula is the sharpest ever, constructed using data from the Hubble Space Telescope's Advanced Camera for Surveys and the European Southern Observatory's La Silla 2.2 meter telescope. The mosaic contains a billion pixels at full resolution and reveals about 3,000 stars.

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This is a golden oldie that richly deserves to be recycled!

Even me, the angry color critic, is happy with the colors here! The Orion Nebula was apparently imaged through nine different filters for this image - check out this page!

Speaking about colors, note that the gaseous region near the Trapezium (the small cluster of blue-white stars responsible for ionizing the Orion Nebula) is greenish-white in color. The greenish tint comes from doubly ionized oxygen. You can actually see the faintly greenish tint of this part of the Orion Nebula through a telescope, as in this fine picture by J. R. Henley: http://www.starfieldobservatory.com/ima ... -%20xa.jpg. In any case, it's fun to compare what you can see through a "normal" telescope (as J.R. Henley showed us) with what Hubble revealed in this photo!

Also note, in today's APOD, the fantastic structures in the gas and dust in the Orion Nebula. You can see a few "proplyds", thick disks of gas and dust surrounding newborn stars. These disks are likely solar systems in the making.

This is a great image!

Ann

http://hubblesite.org/news/2006/01
http://www.spacetelescope.org/news/heic0601/
http://www.spitzer.caltech.edu/news/247-ssc2006-21

Compare to three different LRGB images
http://apod.nasa.gov/apod/ap081023.html
http://apod.nasa.gov/apod/ap061120.html
http://apod.nasa.gov/apod/ap040927.html

Ann wrote:Also note, in today's APOD, the fantastic structures in the gas and dust in the Orion Nebula. You can see a few "proplyds", thick disks of gas and dust surrounding newborn stars. These disks are likely solar systems in the making.

APOD: Planetary Systems Now Forming in Orion (2009 Dec 22)
http://asterisk.apod.com/viewtopic.php?f=9&t=17875

APOD Collection: M42: The Orion Nebula

Up in the upper left.....is that SPAWN????

This is an AWESOME PIC of my all time favorite objects!
Thanks.

:---[===] *

Below and to the left of center are three foreground stars in a row. They're pointing at a tube shaped something off to the right (it shows up better on the zoom-able Hubblesite page). I would guess it would appear bigger if it were in earth orbit...a glitch perhaps? One of those proplyds mentioned in Ann's post?

yasgur wrote:Below and to the left of center are three foreground stars in a row. They're pointing at a tube shaped something off to the right (it shows up better on the zoom-able Hubblesite page). I would guess it would appear bigger if it were in earth orbit...a glitch perhaps? One of those proplyds mentioned in Ann's post?

Those foreground stars aren't necessarily so "foreground". The one farthest to the left won't show up in my software! But if you look more closely, you can see that this star appears "soft", as if it was embedded in nebulosity (as is probably is). Also, the two other stars have "stronger" diffraction spikes than the leftmost one, suggesting they shine brighter than the star to the left. Much of the light from the star on the left may come from illuminated dust: it's a reflection nebula.

But as for the tube shaped thing, it looks like some sort of jet to me. Not a narrow, energetic jet, but a jet all the same. It could be a byproduct of very many things going on in this fantastic part of the sky!

Ann

Beautiful picture; can you imagine the view of Orion Nebula if the James Webb focuses on it after it is launched?

I love the Apod Orion Nebulae collection!

I can't choose wich one I like most, Spitzer's are stunning and others reveal different aspects of the nebulae!

I can see in today's Apod a fetus in a woman's reddish womb, it's resting on the right side...

Gorgeous image but once again Dr. Nemiroff decided to apply a global sharpening filter to an iconic image. I must say this disrespects the authors of the image since I assume he did not ask nor receive permission to do so. In the least the courteous thing to do would be to ask the authors to sharpen the image themselves as they are probably much more skilled at "selectively" doing so. This is a very disappointing issue as it makes the statment "who cares about the rights of the author of the image". I would challenge Dr. Nemiroff to post a survey on the APOD page asking the opinions of astrophotographers about their feelings regarding this practice.

Robert Gendler

And, yet, it doesn't really seem that sharp, Rob. I mean, clearly some sharpening has been done, but at the same time some blurring also seems to have occurred. The colors for the edited image are also quite bad (it has been converted to sRGB... BAD!). Hmmm...

So that's what has happened. I noticed that the "texture" of the picture didn't seem to be the same on the "APOD front page" as on the "high resolution page".

I agree, it's a pity if this sharpening has been done without asking permission of the original photographers.

Ann

Dr. Gendler, I'm quite dismayed and disappointed to read your post; I thought you better than that.

robgendler wrote:Gorgeous image but once again Dr. Nemiroff decided to apply a global sharpening filter to an iconic image. I must say this disrespects the authors of the image since I assume he did not ask nor receive permission to do so. In the least the courteous thing to do would be to ask the authors to sharpen the image themselves as they are probably much more skilled at "selectively" doing so. This is a very disappointing issue as it makes the statment "who cares about the rights of the author of the image". I would challenge Dr. Nemiroff to post a survey on the APOD page asking the opinions of astrophotographers about their feelings regarding this practice.

Robert Gendler

This publicly released image has been cropped as well. The image was bit fuzzy and comparing the sharpened to the original image I thought the sharpened one looked significantly better. The detail brought out is, in my opinion, absolutely fascinating. Just look at the flowing dust lanes in the sharpened image -- they are absolutely stunning. And its NOT fiction! To see the (still great) unsharpened version, just click through the main image. In my role as an APOD editor, I do what many other editors do -- change things so as to better appeal to my perceived audiences. In general, on APOD images, I crop frequently, sharpen rarely (only a handful of times over 17 years), and on extremely rare occasions I will also change a color table. (Quiz to whoever is reading: can you find a color table change?) My perceived audience is NOT astrophotographers -- my perceived audience is the interested and intelligent public.

Even so, in 17 years the number of times I have been asked by an astrophotographer to undo my photo edits on their image is -- zero. Only one person has ever complained -- Dr. Gendler. Dr. Gendler is clearly a gifted astrophotographer as well as amazing at digitally rendering images, in particular astronomical images. I am not. I do value his opinion as well as the opinion of other accomplished astrophotographers. Further, knowing his opinion I would NEVER sharpen one of his images. Even so -- if there are any astrophotographers out there whose own APOD-appearing image(s) were sharpened against their will or liking, please respond to this post.

Dr. Gendler and I have debated this over email previously. There, he said that his main concern is that sharpening insults the work of the astrophotographer. This image is public domain and so legality is not an issue here. I can see that might be a concern more generally, though, in some cases. As would cropping. But not in every case. Sometimes editing actually improve images. And I think when a photographer submits a work, it is with the understanding that it might be changed in some way by an editor before it appears. Previously, Dr. Gendler replied to this point that National Geographic editors, for example, would never sharpen a submitted image. My response was that that I believe that they would. They are, however, rarely sent fuzzy images, since most good landscape images of the Earth are extremely sharp already. More generally, I believe that other photo editors would change and/or sharpen images. Experienced photographers might know which editors are likely to do what -- and choose their submission venues -- and publication requirements -- accordingly.

- RJN

owlice wrote:Dr. Gendler, I'm quite dismayed and disappointed to read your post; I thought you better than that.

Owlice, I'm sorry to say that you're out of line in this response.

The APOD image on the main page is indeed oversharpened, and Rob is quite right to point it out. It turns a beatiful, subtle image into an overprocessed-looking result.

Speaking of which...

I'll also add that to this day RJN / the APOD preparers have failed to embrace color-management, and so an image published in the Adobe RGB color space, which allows for richer reds among other things, is being degraded by the ignorance / removal of the color profile.
-Noel

No one else has complained because most astrophotographers feel so grateful to have one of their images on APOD they would not want to jeapordize their chances of getting another one. I can assure you that in astrophotography circles this practice is viewed very negatively. The real question is not whether or why sharpening appeals to RJN or not. The real question is the deliberate global manipulation of an image without the expressed permission of the author of that image. It demonstrates an implicit lack of respect to the author of that image. Cropping is not in the same category. It may be necessary to crop an image so it will fit the APOD template. Astrophotographers spend enormous amounts of time and other resources to create the images that contribute to making APOD the incredible site it has become. The editors write wonderful desciptions to complement those images. Both the editors and the astrophotographers are equally important to the success of APOD. So why not extend a little common courtesy to the imagers who give so much of themselves. They know more than anyone how much sharpening is appropriate for an image.

Ann wrote: Speaking about colors, note that the gaseous region near the Trapezium (the small cluster of blue-white stars responsible for ionizing the Orion Nebula) is greenish-white in color.

Ann, that's what I first came here to comment about, before being distracted by Owlice's comment above.

The bright Trapezium region of M42, as photographed with a general photography camera (e.g., a Canon dSLR) is one of the most beautiful shades of teal, and it bothered me not to see that shade here, in what otherwise seems like a gorgeous attempt to show "visual" coloration.

As an example, this is what a camera that otherwise produces daytime images with believable color "sees" of M42:
-Noel

NoelC wrote:

owlice wrote:Dr. Gendler, I'm quite dismayed and disappointed to read your post; I thought you better than that.

Owlice, I'm sorry to say that you're out of line in this response.

I'm not at all out of line, Noel; you're entitled to think so, however.

owlice wrote:Dr. Gendler, I'm quite dismayed and disappointed to read your post; I thought you better than that.

Interesting. I think you have little faith in the APOD editors ability to accept constructive criticism. They did not get where they are by having a thin skin.

Dr. Gendler, I know the APOD editors are able to accept constructive criticism; they still answer my emails! Sheesh. I have plenty of faith in the editors.

If this needs further discussion, please feel free to contact me via email. Thank you.

Gorgeous picture !

Visually, one of the best pictures ever, to examine and paw through at maximum resolution. The star bow wave not far from the 3 stars is famous and exceptionally beautiful. The propolyds are worth searching for. And all the stars lighting up bubbles in the gas, hard to believe that this is reality. Thanks for posting, whatever the color, and thanks to those who provided the other links.

Star bow wave in Orion : http://ousterhout.net/slideshows/hst/hu ... %20M42.htm

Thanks for posting whatever the color, and thanks to those who provided the other links.

PS
Indignant Ad hominem attacks are usually a result of poor social skills. Not taking offense and being a good listener shows good social skills.
As for the issue itself, I will enjoy the links I'm sure.

ScienceShot: Impostors in the Orion Nebula?

The Orion Nebula, 1350 light-years from Earth, appears to the naked eye as a fuzzy star in the sword of Orion. The nebula is spawning stars large and small, so observers often study it to learn about star birth. Now, however, astronomers say that at least 10% to 20% of the thousands of stars ascribed to the 1-million-year-old Orion Nebula cluster actually belong to the Iota Orionis cluster, which lies just in front of the Orion Nebula and is four to five times older. The finding means astronomers must revisit earlier conclusions about young stars, the researchers write in a future issue of Astronomy & Astrophysics. For example, planet-forming disks tend to disperse with time, so if some of the Orion stars are older than thought, a greater percentage of the youngest ones sport protoplanetary disks. And that means there could be an even greater abundance of strange new worlds for astronomers to discover.

Orion Revisited I. The massive cluster in front of the Orion Nebula Cluster

• J. Alves, H. Bouy > arXiv.org > astro-ph > arXiv:1209.3787 > 17 Sep 2012