APOD: The California Nebula (2016 Jan 12)

Comments and questions about the APOD on the main view screen.
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APOD: The California Nebula (2016 Jan 12)

Post by APOD Robot » Tue Jan 12, 2016 5:15 am

Image The California Nebula

Explanation: What's California doing in space? Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud by chance echoes the outline of California on the west coast of the United States. Our own Sun also lies within the Milky Way's Orion Arm, only about 1,500 light-years from the California Nebula. Also known as NGC 1499, the classic emission nebula is around 100 light-years long. On the featured image, the most prominent glow of the California Nebula is the red light characteristic of hydrogen atoms recombining with long lost electrons, stripped away (ionized) by energetic starlight. The star most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot, bluish Xi Persei just to the right of the nebula. A regular target for astrophotographers, the California Nebula can be spotted with a wide-field telescope under a dark sky toward the constellation of Perseus, not far from the Pleiades.

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Re: APOD: The California Nebula (2016 Jan 12)

Post by Ann » Tue Jan 12, 2016 5:23 am

This is a very beautiful APOD! :D

The image is very clearly an RGB picture, but the nebula is separated in colors in a way that I don't really expect from RGB images, which seems to suggest different levels of ionization. If that is true - and that is a very big "if" - then the bluish color closest to Xi Persei might represent OIII emission, and the brownish color farthest from Xi Persei might be SII. Obviously the red part of the nebula gets its color from Ha emission.

The red part of the nebula opposite Xi Persei looks very dramatic, like the sea during a storm. All in all, it is a very beautiful and dramatic APOD!

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Re: APOD: The California Nebula (2016 Jan 12)

Post by Case » Tue Jan 12, 2016 6:09 am

Ann wrote:The image is very clearly an RGB picture, but the nebula is separated in colors in a way that I don't really expect from RGB images
Antonio Farmakopoulos has some details listed on his website: Hα 18x900 sec bin 1x, RGB 12x600 sec bin 1x. Plus post processing, of course, which might make it a bit more different compared to other images of the same nebula.
I love the detail and structure of the bright parts of the nebula in this image.

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Re: APOD: The California Nebula (2016 Jan 12)

Post by Nitpicker » Tue Jan 12, 2016 7:05 am


heehaw

Re: APOD: The California Nebula (2016 Jan 12)

Post by heehaw » Tue Jan 12, 2016 10:44 am

Nitpicker wrote:I never knew this before:
https://en.wikipedia.org/wiki/Island_of_California
I believe that Republicans currently use this map....

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Re: APOD: The California Nebula (2016 Jan 12)

Post by neufer » Tue Jan 12, 2016 1:48 pm

Nitpicker wrote:
I never knew this before: https://en.wikipedia.org/wiki/Island_of_California
Click to play embedded YouTube video.
_A Miscellany of American Place Names_
by Jim Cocola

<<California itself was named by Hernan Cortes, who became the first European to explore it in 1535. The name is said to originate from a best-selling romance of the period, titled Las Sergas de Esplandian. This fanciful novel of chivalry, written by popular writer Garcia Ordonez de Montalvo, details the exploits of a courtier named Esplandian, who travels extensively in search of adventures and adventuresses. The book mentions "Las Sergas de Esplandian", a magical island ruled over by the ever-youthful Queen Caliphia. The isle is populated by a race of cave-dwelling warrior women, and because no men exist on the island, the women form unions with foreign men to bear children during peacetime. During wartime, however, the foreign men become fodder for cannibalistic feasts, and heir unfortunate sons are turned into puppy chow for the large population of pet griffins on the island. Only the daughters remain, raised on a combination of tough love and (male) human flesh. A society promoting itself as heaven on earth, where people refuse to grow older and the family is disintegrating; a land where the sex is casual, the women are man-eaters and the pets are exotic, ridiculous and overfed.>>
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Re: APOD: The California Nebula (2016 Jan 12)

Post by Chris Peterson » Tue Jan 12, 2016 3:30 pm

Case wrote:
Ann wrote:The image is very clearly an RGB picture, but the nebula is separated in colors in a way that I don't really expect from RGB images
Antonio Farmakopoulos has some details listed on his website: Hα 18x900 sec bin 1x, RGB 12x600 sec bin 1x. Plus post processing, of course, which might make it a bit more different compared to other images of the same nebula.
I love the detail and structure of the bright parts of the nebula in this image.
I take his notation to mean that this is processed as an LRGB image, with the L channel utilizing the Ha data (and RGB mapped as normal). This has the effect of emphasizing the brightness of the hydrogen emission and improving the nebula S/N without saturating the stars.
Chris

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Re: APOD: The California Nebula (2016 Jan 12)

Post by Ron-Astro Pharmacist » Tue Jan 12, 2016 5:00 pm

When the electrons in hydrogen atoms transition between levels to create a H-alpha photon we see the result in today's APOD. When this happens in the inner shell of a more complex atoms, through a series of events, it leads to the ejection of an Auger electron. Quite curiously this process may one day lead to therapeutic treatments for some forms of cancer.

I'm only worried some politicians may get light of this and mistakenly trumpet for "election" shifts. Though it already appears California has been transitioned to a "red state". :wink:
Last edited by Ron-Astro Pharmacist on Tue Jan 12, 2016 5:18 pm, edited 1 time in total.
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Re: APOD: The California Nebula (2016 Jan 12)

Post by MarkBour » Tue Jan 12, 2016 5:02 pm

Newb question of the week. I was looking up Hydrogen alpha and noted that the Ha line is actually produced by an electron dropping from n=3 to n=2 in the hydrogen, giving off a 656 nm photon ("Balmer series"). An electron dropping from n=2 to n=1 will give off a more energetic 122 nm photon ("Lyman series").

My intuition is that for a typical cloud of hydrogen in space that is being ionized and emitting light from electron recapture, there would be even more Lyman alpha emissions than Balmer alpha emissions. Is this correct? Then I see some mentions of why the Balmer alpha is more important to astronomers (traditionally) than the Lyman alpha, but I'm certainly hazy on what those reasons are. Either interference from our Sun or absorption by our atmosphere seem to be at issue.
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Re: APOD: The California Nebula (2016 Jan 12)

Post by Chris Peterson » Tue Jan 12, 2016 5:40 pm

MarkBour wrote:Newb question of the week. I was looking up Hydrogen alpha and noted that the Ha line is actually produced by an electron dropping from n=3 to n=2 in the hydrogen, giving off a 656 nm photon ("Balmer series"). An electron dropping from n=2 to n=1 will give off a more energetic 122 nm photon ("Lyman series").

My intuition is that for a typical cloud of hydrogen in space that is being ionized and emitting light from electron recapture, there would be even more Lyman alpha emissions than Balmer alpha emissions. Is this correct?
Not sure about that. Certainly, in theory there are more Lyman emission lines than Balmer lines. But the actual energetics in a nebula are complex, and I don't know what the actual distribution looks like.
Then I see some mentions of why the Balmer alpha is more important to astronomers (traditionally) than the Lyman alpha, but I'm certainly hazy on what those reasons are. Either interference from our Sun or absorption by our atmosphere seem to be at issue.
The Lyman lines are all in the UV. That's a problem for ground-based astronomy because of atmospheric interference, and it's a technological problem, as well, since it is generally easier and cheaper to image in the visible band than in the UV. We've recently developed good UV imaging systems, but still, for best results these need to be operated above the atmosphere.
Chris

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Re: APOD: The California Nebula (2016 Jan 12)

Post by starsurfer » Tue Jan 12, 2016 5:48 pm

I'd really like it if there was either an Alaska Nebula or a Canada Nebula. :D :lol2:

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Re: APOD: The California Nebula (2016 Jan 12)

Post by Ron-Astro Pharmacist » Tue Jan 12, 2016 6:45 pm

starsurfer wrote:I'd really like it if there was either an Alaska Nebula or a Canada Nebula. :D :lol2:
I suppose the North American nebula represents too far south but they have the Aurora Borealis. Each land mass only gets one major attraction. :no:
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Re: APOD: The California Nebula (2016 Jan 12)

Post by Boomer12k » Tue Jan 12, 2016 7:56 pm

And WOW...that is just a SUPER image of it too....

Like a red neon bulb.

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Re: APOD: The California Nebula (2016 Jan 12)

Post by panhalt » Tue Jan 12, 2016 8:53 pm

That California drought is really getting bad.

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Re: APOD: The California Nebula (2016 Jan 12)

Post by BMAONE23 » Tue Jan 12, 2016 10:06 pm

panhalt wrote:That California drought is really getting bad.
I dunno...If the current rain keeps up, it could be a wash

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Re: APOD: The California Nebula (2016 Jan 12)

Post by neufer » Tue Jan 12, 2016 10:33 pm

Click to view full size image 1 or image 2
BMAONE23 wrote:
panhalt wrote:
That California drought is really getting bad.
I dunno...If the current rain keeps up, it could be a wash
  • The situation is a lot better
    west of Sacramento at least. :arrow:
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Re: APOD: The California Nebula (2016 Jan 12)

Post by Ron-Astro Pharmacist » Tue Jan 12, 2016 10:56 pm

Earthquakes, rain or fire? Makes one wonder if the cartographers knew something...
Click to play embedded YouTube video.
Groovy!
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