by Ann » Tue May 28, 2019 11:08 pm
Boomer12k wrote: ↑Tue May 28, 2019 10:15 pm
AVAO wrote: ↑Tue May 28, 2019 12:39 pm
What a great composite picture!
But what is the blue oval-shaped ring in the left upper half of the picture? Hydrogen, oxygen, or sulfur?
Generally Blue... is Oxygen in this type image...Sulfur is Yellow, and Hydrogen is Red...
I don't know if that changes with the Broadband RGB blended though...
:---[===] *
NGC 3572. Image Credit & Copyright: Andrew Campbell.
NGC 3572. Image credit: ESO/Digitized Sky Survey 2.
Indeed, oxygen is normally blue in images like these. Hydrogen is normally green and sulphur is normally red.
In today's APOD, it seems to me that the blue parts of the nebula are "too thick" to be oxygen. The "main nebular strands" of the nebula are blue in the APOD, and normally these features would be dominated by hydrogen (and some sulphur).
Think of a nebula as a vase. I believe that the "walls" of the nebula, the "vase" of it, would be hydrogen. Inside the "vase", inside the "nebular walls", there would be oxygen. What about sulphur? Oh... ask someone who gets a kick out of red things!
That's why I'm guessing that "the walls of nebula NGC 3572" must be hydrogen, and that hydrogen, therefore, might be blue in this APOD.
Compare the APOD with the ESO/Digitized Sky Survey 2 image, where hydrogen is certainly red, and you can see that the brightest features of the nebula in that picture are for the most part the ones that look blue in the APOD.
Ann
[quote=Boomer12k post_id=292578 time=1559081720 user_id=120851]
[quote=AVAO post_id=292555 time=1559047172 user_id=144694]
What a great composite picture!
But what is the blue oval-shaped ring in the left upper half of the picture? Hydrogen, oxygen, or sulfur?
[/quote]
Generally Blue... is Oxygen in this type image...Sulfur is Yellow, and Hydrogen is Red...
I don't know if that changes with the Broadband RGB blended though...
:---[===] *
[/quote]
[float=left][img2]https://apod.nasa.gov/apod/image/1905/NGC3572_Campbell_960.jpg[/img2][c][size=85]NGC 3572. Image Credit & Copyright: Andrew Campbell.[/size][/c][/float] [float=right][img2]https://scitechdaily.com/images/ESO-Views-Star-Cluster-NGC-3572.jpg[/img2][c][size=85]NGC 3572. Image credit: ESO/Digitized Sky Survey 2.[/size][/c][/float]
Indeed, oxygen is normally blue in images like these. Hydrogen is normally green and sulphur is normally red.
In today's APOD, it seems to me that the blue parts of the nebula are "too thick" to be oxygen. The "main nebular strands" of the nebula are blue in the APOD, and normally these features would be dominated by hydrogen (and some sulphur).
[float=right][img2]https://sotahem.se/images/zoom/vasglas.jpg[/img2][/float]
Think of a nebula as a vase. I believe that the "walls" of the nebula, the "vase" of it, would be hydrogen. Inside the "vase", inside the "nebular walls", there would be oxygen. What about sulphur? Oh... ask someone who gets a kick out of red things! :wink:
That's why I'm guessing that "the walls of nebula NGC 3572" must be hydrogen, and that hydrogen, therefore, might be blue in this APOD.
Compare the APOD with the ESO/Digitized Sky Survey 2 image, where hydrogen is certainly red, and you can see that the brightest features of the nebula in that picture are for the most part the ones that look blue in the APOD.
Ann