APOD: Stargate Milky Way (2022 Aug 17)

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APOD: Stargate Milky Way (2022 Aug 17)

Post by APOD Robot » Wed Aug 17, 2022 4:05 am

Image Stargate Milky Way

Explanation: There is a huge gate of stars in the sky, and you pass through it twice a day. The stargate is actually our Milky Way Galaxy, and it is the spin of the Earth that appears to propel you through it. More typically, the central band of our Milky Way appears as a faint band stretching across the sky, only visible in away from bright city lights. In a long-exposure wide-angle image from a dark location like this, though, the Milky Way's central plane is easily visible. The featured picture is a digital composite involving multiple exposures taken on the same night and with the same camera, but employing a stereographic projection that causes the Milky Way to appear as a giant circular portal. Inside the stargate-like arc of our Galaxy is a faint stripe called zodiacal light -- sunlight reflected by dust in our Solar System. In the foreground are cacti and dry rocks found in the rough terrain of the high desert of Chile, not far from the El Sauce Observatory and the developing Vera Rubin Observatory, the latter expected to begin routine operations in 2024.

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by FLPhotoCatcher » Wed Aug 17, 2022 4:58 am

Three days ago, someone on reddit downloaded and processed raw JWST data. Here's the photo and the link to reddit:

https://www.reddit.com/r/jameswebb/comm ... jwst_data/
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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by Chris Peterson » Wed Aug 17, 2022 12:43 pm

FLPhotoCatcher wrote: Wed Aug 17, 2022 4:58 am Three days ago, someone on reddit downloaded and processed raw JWST data. Here's the photo and the link to reddit:

https://www.reddit.com/r/jameswebb/comm ... jwst_data/
Okay, but... relevance to today's APOD?
Chris

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by orin stepanek » Wed Aug 17, 2022 1:15 pm

StargateMilkyWay_Oudoux_1800.jpg
I watched some Stargate shows when they started on TV! I like
Sci-Fi; but the show didn't appeal to me!
LightPollutionPan_Slovinsky_960_labeled.jpg
I lived on the edge of a small town, and the Milky-way was like in #4!
Today I can't see it at all in the city! 🙁
istockphoto-1240888678-170667a.jpg
I had a tomcat called Cinnamon that looked like this! Thanks for the
memory Judy! :D
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Smile today; tomorrow's another day!

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by De58te » Wed Aug 17, 2022 1:58 pm

Yup that's from the JWST alright. I've noticed you can tell there are 6 star spikes whereas older telescopes like Hubble only show 4 star spikes. The picture is the NGC 7469 galaxy. But I like the Hubble picture of NGC 7469 better. It looks more detailed for a poster. Although the infrared is scientifically important. Hubble site; https://esahubble.org/images/heic0810cd/

But one question comes to my mind. I thought the JWST is supposed to be 3 or 4 times more powerful than the Hubble? Yet why then is the Hubble picture of NGC 7469 the same size and even looks more focused?

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by Chris Peterson » Wed Aug 17, 2022 2:11 pm

De58te wrote: Wed Aug 17, 2022 1:58 pm Yup that's from the JWST alright. I've noticed you can tell there are 6 star spikes whereas older telescopes like Hubble only show 4 star spikes. The picture is the NGC 7469 galaxy. But I like the Hubble picture of NGC 7469 better. It looks more detailed for a poster. Although the infrared is scientifically important. Hubble site; https://esahubble.org/images/heic0810cd/

But one question comes to my mind. I thought the JWST is supposed to be 3 or 4 times more powerful than the Hubble? Yet why then is the Hubble picture of NGC 7469 the same size and even looks more focused?
What is "powerful"? Both instruments have about the same resolution. They operate in different wavelength ranges, and the JWST, with its larger mirror, can see dimmer objects. Which telescope will produce apparently sharper images depends very much on the wavelengths the object is emitting.
Chris

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by VictorBorun » Wed Aug 17, 2022 9:00 pm

I don't understand this APOD at all. The shape of Milky Way looks unusual, the shape of the ground looks usual

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by johnnydeep » Wed Aug 17, 2022 9:03 pm

I'd think not everyone on Earth "passes through" the Milky Way (plane) twice per day. You have to be far enough away from the poles for the Earth's rotation to do the moving, correct? (Unless my 3D sense has failed me again.)

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by Chris Peterson » Wed Aug 17, 2022 9:42 pm

VictorBorun wrote: Wed Aug 17, 2022 9:00 pm I don't understand this APOD at all. The shape of Milky Way looks unusual, the shape of the ground looks usual
You're looking at an image that spans more than 180°. A big section of a sphere which has to be mapped to a plane. That means something has to be distorted. You could make the Milky Way look like a linear band, but that would require making the horizon curved.
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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by VictorBorun » Thu Aug 18, 2022 3:03 am

Chris Peterson wrote: Wed Aug 17, 2022 9:42 pm
VictorBorun wrote: Wed Aug 17, 2022 9:00 pm I don't understand this APOD at all. The shape of Milky Way looks unusual, the shape of the ground looks usual
You're looking at an image that spans more than 180°. A big section of a sphere which has to be mapped to a plane. That means something has to be distorted. You could make the Milky Way look like a linear band, but that would require making the horizon curved.
how come the cactuses in the ground are not curved/skewed/towered/stooped?

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by VictorBorun » Thu Aug 18, 2022 3:22 am

johnnydeep wrote: Wed Aug 17, 2022 9:03 pm I'd think not everyone on Earth "passes through" the Milky Way (plane) twice per day. You have to be far enough away from the poles for the Earth's rotation to do the moving, correct? (Unless my 3D sense has failed me again.)

This 3d info graphics shows that:

90.0° North or South: for an observer on a pole their zenith stays in the pole and Milky Way never passes that zenith
62.9° North or South: once in 24 hours their zenith grazes a Milky Way's point making our Galactic disk divide the sky into equal halves for a moment
62.8° or less N or S: twice in 24 hours their zenith crosses one of the 2 Milky Way's points
0°: those 2 moments are 12 hours apart and those Milky Way's points are diametric opposites

The last observer can see Milky Way like sort of jump rope going round every 24 hours and cannot see another one because of the day's skyshine

Image

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by FLPhotoCatcher » Thu Aug 18, 2022 3:55 am

De58te wrote: Wed Aug 17, 2022 1:58 pm Yup that's from the JWST alright. I've noticed you can tell there are 6 star spikes whereas older telescopes like Hubble only show 4 star spikes. The picture is the NGC 7469 galaxy. But I like the Hubble picture of NGC 7469 better. It looks more detailed for a poster. Although the infrared is scientifically important. Hubble site; https://esahubble.org/images/heic0810cd/

But one question comes to my mind. I thought the JWST is supposed to be 3 or 4 times more powerful than the Hubble? Yet why then is the Hubble picture of NGC 7469 the same size and even looks more focused?
I'm not sure how you found it, but thanks for the galaxy ID.

And what is the bright object in the center of the galaxy that shows up in the JWST image? It must be very bright in infrared, but not visible. Or maybe it's an outburst from the central black hole?

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by Chris Peterson » Thu Aug 18, 2022 5:32 am

VictorBorun wrote: Thu Aug 18, 2022 3:03 am
Chris Peterson wrote: Wed Aug 17, 2022 9:42 pm
VictorBorun wrote: Wed Aug 17, 2022 9:00 pm I don't understand this APOD at all. The shape of Milky Way looks unusual, the shape of the ground looks usual
You're looking at an image that spans more than 180°. A big section of a sphere which has to be mapped to a plane. That means something has to be distorted. You could make the Milky Way look like a linear band, but that would require making the horizon curved.
how come the cactuses in the ground are not curved/skewed/towered/stooped?
They are.
Chris

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by VictorBorun » Thu Aug 18, 2022 6:21 am

FLPhotoCatcher wrote: Thu Aug 18, 2022 3:55 am
De58te wrote: Wed Aug 17, 2022 1:58 pm Yup that's from the JWST alright. I've noticed you can tell there are 6 star spikes whereas older telescopes like Hubble only show 4 star spikes. The picture is the NGC 7469 galaxy. But I like the Hubble picture of NGC 7469 better. It looks more detailed for a poster. Although the infrared is scientifically important. Hubble site; https://esahubble.org/images/heic0810cd/

But one question comes to my mind. I thought the JWST is supposed to be 3 or 4 times more powerful than the Hubble? Yet why then is the Hubble picture of NGC 7469 the same size and even looks more focused?
I'm not sure how you found it, but thanks for the galaxy ID.

And what is the bright object in the center of the galaxy that shows up in the JWST image? It must be very bright in infrared, but not visible. Or maybe it's an outburst from the central black hole?
somehow to fit the two you have to flip one of them
NGC 7469 Webb-.png
NGC 7469 Hubble-.png
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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by VictorBorun » Thu Aug 18, 2022 6:25 am

and if you fit NGC 7469, then IC 5283 dances
Click to view full size image 1 or image 2

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by johnnydeep » Thu Aug 18, 2022 12:15 pm

VictorBorun wrote: Thu Aug 18, 2022 6:25 am and if you fit NGC 7469, then IC 5283 dances
Click to view full size image 1 or image 2
Nice overlay job (as usual!), but are you trying to point out anything in particular here? IC 5283 is barely in the frame of the JWST image.
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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by VictorBorun » Thu Aug 18, 2022 8:31 pm

johnnydeep wrote: Thu Aug 18, 2022 12:15 pm
VictorBorun wrote: Thu Aug 18, 2022 6:25 am and if you fit NGC 7469, then IC 5283 dances
IC 5283 is barely in the frame of the JWST image.
At first glance Webb's pic (flipped, rotated and scaled, but not skewed) has the starfield left of the centre jump a little to left.
Can it be star's tangential drift in a few years since Hubble's pic?
But then some really bright stellar clusters in IC 5283's upper arm do jump by the same angle and direction.
So this disfit is technical. Some error in the stitching of a pic from narrow angle frames?
Some aberration in a main mirror?
My error in fitting Webb to Hubble? Maybe I fitted the wrong things like a drifting starfield; maybe it's only only distant galaxies that should be used
Last edited by VictorBorun on Thu Aug 18, 2022 8:41 pm, edited 1 time in total.

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by johnnydeep » Thu Aug 18, 2022 8:38 pm

VictorBorun wrote: Thu Aug 18, 2022 8:31 pm
johnnydeep wrote: Thu Aug 18, 2022 12:15 pm
VictorBorun wrote: Thu Aug 18, 2022 6:25 am and if you fit NGC 7469, then IC 5283 dances
IC 5283 is barely in the frame of the JWST image.
At first glance Webb's pic (flipped, rotated and scaled, but not skewed) has the starfield left of the centre jump a little to left.
Can it be star's tangential drift in a few years since Hubble's pic?
But then some really bright stellar clusters in IC 5283's upper arm do jump by the same angle and direction.
So this disfit is technical. Some error in the stitching of a pic from narrow angle frames?
Some aberration in a main mirror?
Ok, yes almost all the stars near IC 5283 seem to shift a bit between the two images. I can't imagine anything real is going on besides photo processing artifacts.
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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by Ann » Thu Aug 18, 2022 8:47 pm

FLPhotoCatcher wrote: Thu Aug 18, 2022 3:55 am
De58te wrote: Wed Aug 17, 2022 1:58 pm Yup that's from the JWST alright. I've noticed you can tell there are 6 star spikes whereas older telescopes like Hubble only show 4 star spikes. The picture is the NGC 7469 galaxy. But I like the Hubble picture of NGC 7469 better. It looks more detailed for a poster. Although the infrared is scientifically important. Hubble site; https://esahubble.org/images/heic0810cd/

But one question comes to my mind. I thought the JWST is supposed to be 3 or 4 times more powerful than the Hubble? Yet why then is the Hubble picture of NGC 7469 the same size and even looks more focused?
I'm not sure how you found it, but thanks for the galaxy ID.

And what is the bright object in the center of the galaxy that shows up in the JWST image? It must be very bright in infrared, but not visible. Or maybe it's an outburst from the central black hole?

It is mid-infrared light from the accretion disk around the black hole. The accretion disk is very bright in mid infrared.

Compare the image of NGC 7469 with James Webb's MIRI instrument image of Stephan's Quintet. Note the brilliance at the center of NGC 7319 (the galaxy at top right). The center of this galaxy looks unremarkable in optical light, but at mid infrared wavelengths, the accretion disk shines brightly.

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Re: APOD: Stargate Milky Way (2022 Aug 17)

Post by VictorBorun » Fri Aug 19, 2022 10:15 am

Ann wrote: Thu Aug 18, 2022 8:47 pm It is mid-infrared light from the accretion disk around the black hole. The accretion disk is very bright in mid infrared.
Compare the image of NGC 7469 with James Webb's MIRI instrument image of Stephan's Quintet. Note the brilliance at the center of NGC 7319 (the galaxy at top right). The center of this galaxy looks unremarkable in optical light, but at mid infrared wavelengths, the accretion disk shines brightly.
Ann
JWST team checked for high Doppler's velocities in the implied accretion disk.
200 km/s orbital speeds are detected:
Image