APOD: Cygnus Skyscape (2019 Jul 25)

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APOD: Cygnus Skyscape (2019 Jul 25)

Post by APOD Robot » Thu Jul 25, 2019 4:11 am

Image Cygnus Skyscape

Explanation: In brush strokes of interstellar dust and glowing hydrogen gas, this beautiful skyscape is painted across the plane of our Milky Way Galaxy near the northern end of the Great Rift and the constellation Cygnus the Swan. Composed with three different telescopes and about 90 hours of image data the widefield mosaic spans an impressive 24 degrees across the sky. Alpha star of Cygnus, bright, hot, supergiant Deneb lies near top center. Crowded with stars and luminous gas clouds Cygnus is also home to the dark, obscuring Northern Coal Sack Nebula, extending from Deneb toward the center of the view. The reddish glow of star forming regions NGC 7000, the North America Nebula and IC 5070, the Pelican Nebula, are just left of Deneb. The Veil Nebula is a standout below and left of center. A supernova remnant, the Veil is some 1,400 light years away, but many other nebulae and star clusters are identifiable throughout the cosmic scene. Of course, Deneb itself is also known to northern hemisphere skygazers for its place in two asterisms -- marking the top of the Northern Cross and a vertex of the Summer Triangle.

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Ann
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Re: APOD: Cygnus Skyscape (2019 Jul 25)

Post by Ann » Thu Jul 25, 2019 6:04 am

APOD Robot wrote:

Composed with three different telescopes and about 90 hours of image data the widefield mosaic spans an impressive 24 degrees across the sky.
I am in awe at the amount of work that went into producing today's APOD. The picture is very impressive, too.

My objection - if that is an objection at all - is that the photographer teased so much hydrogen alpha light out of this celestial area that the familiar bright nebular objects in Cygnus almost drown in all the red Hα light. It can't be easy for a newbie to pick out the North America nebula (left of bright star Deneb at top) is this "sea of red".

There are a couple of things that I personally appreciate very much about today's APOD. By placing the dark rift of dust in the center of the image (well, top center), the photographer brings home the idea that all this redness belongs, more or less, to the same huge nebular complex. That is not quite true, of course, but much of the nebulosity is probably at more or less the same distance from us.

But not necessarily. I think it was David Malin who once said that northern Cygnus is where a spiral arm in the Milky Way "turns back on itself ", so that we see nebulosities at different distances from us in the Cygnus constellation. The southern counterpart to Cygnus, where the spiral arm "turns back on itself, would be Carina, another nebula-rich part of the sky.

One more thing that I love about today's APOD is that it really brings out the remarkable runaway O-type star 68 Cygni and its nebulosity, Sharpless 119. This great star and its "binary nebula" can be seen at upper left in today's APOD. In my opinon, 68 Cygni and Sharpless 119 are every bit as remarkable as AE Aurigae and the Flaming Star nebula, but 68 Cygni is almost completely ignored! The picture of 68 Cygni and its nebulosity in the attachment is by Davide de Martin.

68 Cygni.png


Finally, I would like to show you a Cygnus skyscape where the Hα light is not pronounced:

The Milky Way in Cepheus and Cygnus.
Thin Air photography.
In the picture at left, the North America Nebula is prominent in the center of the picture, with the Gamma Cygni (Sadr) nebulosity to the lower left of it. The round pink nebula is IC 1396, and the orange star to the right of it is Mu Cephei. Note the prominence of the starlight. In today's APOD, the starlight is often swamped by the Hα light.

Ann
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Re: APOD: Cygnus Skyscape (2019 Jul 25)

Post by starsurfer » Thu Jul 25, 2019 7:43 am

It's even got part of Vulpecula near the bottom right corner of the image!

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Re: APOD: Cygnus Skyscape (2019 Jul 25)

Post by orin stepanek » Thu Jul 25, 2019 10:51 am

Looks like a boiling, churning, inferno! 8-) I see the North America, Pelican, are only a small part of the photo! Deneb is huge! :shock:
Orin

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Re: APOD: Cygnus Skyscape (2019 Jul 25)

Post by De58te » Thu Jul 25, 2019 11:54 am

Oh gosh I'm so sorry guys! I viewed Ann's attachment "68 Cygni.png Viewed 68 times" without first reading the caption. Does this mean my viewing it means they have to rename it 69 Cygni?

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Re: APOD: Cygnus Skyscape (2019 Jul 25)

Post by MarkBour » Thu Jul 25, 2019 7:52 pm

De58te wrote:
Thu Jul 25, 2019 11:54 am
Oh gosh I'm so sorry guys! I viewed Ann's attachment "68 Cygni.png Viewed 68 times" without first reading the caption. Does this mean my viewing it means they have to rename it 69 Cygni?
You can remember her by what she meant to you. To me, she'll always be 68 Cygni.
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