APOD: The Lagoon Nebula is Stars, Gas, and... (2018 Nov 12)

Comments and questions about the APOD on the main view screen.
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APOD: The Lagoon Nebula is Stars, Gas, and... (2018 Nov 12)

Post by APOD Robot » Mon Nov 12, 2018 5:12 am

Image The Lagoon Nebula is Stars, Gas, and Dust

Explanation: The majestic Lagoon Nebula is filled with hot gas and the home for many young stars. Spanning 100 light years across while lying only about 5000 light years distant, the Lagoon Nebula is so big and bright that it can be seen without a telescope toward the constellation of the Archer (Sagittarius). Many bright stars are visible from NGC 6530, an open cluster that formed in the nebula only several million years ago. The greater nebula, also known as M8 and NGC 6523, is named "Lagoon" for the band of dust seen to the left of the open cluster's center. The featured image was taken in three colors with details are brought out by light emitted by Hydrogen. Star formation continues in the Lagoon Nebula as witnessed by the many dark dust-laden globules that exist there.

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Ann
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Re: APOD: The Lagoon Nebula is Stars, Gas, and... (2018 Nov 12)

Post by Ann » Mon Nov 12, 2018 5:54 am

APOD Robot wrote:

The featured image was taken in three colors with details are brought out by light emitted by Hydrogen
So today's APOD is an RGB + Hα image. The picture is striking indeed, and the nebula seems to be unfolding and unfolding like a lightyear-sized rose.

The Lagoon Nebula also looks exceedingly red in today's APOD.

The Lagoon Nebula is red, of course. It is strongly dominated by Hα emission, which is certainly red in color. The problem for me is that this emphasis on Hα emission makes the stars look so insignificant, as they are drowned out by the deluge of redness.
The Lagoon Nebula. Image credit:
László Francsics / Royal Museums Greenwich.
Source: https://astronomynow.com/2015/08/06/her ... francsics/

I'm reminded of something I read very long ago, when the Hubble Telescope was brand new, and astronomers were taking "test pictures" in order to calibrate the HST. So they wanted to photograph a nebula in, I think, the Large Magellanic Cloud. (It was not the Tarantula nebula.) The astronomers were shocked to see that the picture they had taken showed only stars, and no nebulosity at all! But then they realized that starlight is usually so much stronger than nebular light, and they had not used the right filters to capture the nebula.

The picture at right joined the Insight Astronomy Photographer of the Year in 2015. I find it stunningly beautiful, and superior in many ways to today's APOD. There must be many reasons for the superior quality of László Francsics' image, but one of them, I think, is the superb treatment of color.

Ann
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Re: APOD: The Lagoon Nebula is Stars, Gas, and... (2018 Nov 12)

Post by RJN » Mon Nov 12, 2018 3:23 pm

A period (".") was missed at the end of Hydrogen -- just before "Star formation". This typo has now been corrected on the main NASA APOD. We apologize for the omission.

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Re: APOD: The Lagoon Nebula is Stars, Gas, and... (2018 Nov 12)

Post by neufer » Mon Nov 12, 2018 3:36 pm

RJN wrote:
Mon Nov 12, 2018 3:23 pm

A period (".") was missed at the end of Hydrogen -- just before "Star formation".
That period (".") was actually an electron
that was supposed to be missing at the end of Hydrogen
on account of: The Lagoon Nebula is an H II region.
https://en.wikipedia.org/wiki/Lagoon_Nebula wrote:
<<The Lagoon Nebula is classified as an H II region: a region of interstellar atomic hydrogen that is ionized.>>
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Re: APOD: The Lagoon Nebula is Stars, Gas, and... (2018 Nov 12)

Post by MarkBour » Mon Nov 12, 2018 4:40 pm

neufer wrote:
Mon Nov 12, 2018 3:36 pm
That period (".") was actually an electron that was supposed to be missing at the end of Hydrogen
on account of: The Lagoon Nebula is an H II region.
Are you sure about that?
Mark Goldfain

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Re: APOD: The Lagoon Nebula is Stars, Gas, and... (2018 Nov 12)

Post by neufer » Mon Nov 12, 2018 6:04 pm

MarkBour wrote:
Mon Nov 12, 2018 4:40 pm
neufer wrote:
Mon Nov 12, 2018 3:36 pm

That period (".") was actually an electron that was supposed to be missing at the end of Hydrogen
on account of: The Lagoon Nebula is an H II region.
Are you sure about that?
The recent use of lines instead of periods for electron bonds

I consider Friedrich August Kekulé news :!:

https://en.wikipedia.org/wiki/August_Kekul%C3%A9
Art Neuendorffer