Author Topic: JWST VS Hubble, with a slider comparing each telescope images superimposed.  (Read 4590 times)

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Offline BrianHGTopic starter

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Webb VS Hubble, matching shots, with a slider to compare each telescope images superimposed.

Go to this website.

https://www.webbcompare.com/

Just click the zoom on that deep-field, go full screen, use the wheel mouse to zoom to full resolution and enjoy moving the Hubble VS web slider and click-drag panning the entire grouped images around!

Hubble, we appreciate all the once great work you have given us.

I anxiously await whats to come with Webb as the current images have only been taken as test images over the first week of it's final calibration.
« Last Edit: July 16, 2022, 06:23:00 am by BrianHG »
 
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Online Gyro

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Strangely, the images give me the layman impression that if they'd turned up the brightness up on the Hubble, the images would look more similar [EDIT: Looking at SMACS 0723].  The other thing I noticed is that a few stars (or are they galaxies?) are much brighter on Hubble and 'ordinary' on the JWST [EDIT: Carina Nebula, just at the top and above the gas cloud at the middle of the image] - IR versus visible sensors?

Yes there is clearly much sharper focus and much more detail in the gas clouds, stunning images.
« Last Edit: July 16, 2022, 07:33:11 pm by Gyro »
Best Regards, Chris
 

Online tom66

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Here is the best I could get by turning up the brightness and contrast on the the Hubble image of the Southern Ring Nebula - there really is no comparison with Webb. There simply is not the detail in the Hubble image as much as you turn the gain up. 

One thing to realise is that Hubble has its 'spectacles' fitted which correct the mirror error (I'm not sure if these perfectly correct the error or not?) and has older sensors, which certainly have reduced dynamic range and higher noise floors compared to newer sensors.
« Last Edit: July 16, 2022, 08:04:39 pm by tom66 »
 

Online tszaboo

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Someone please fire JJ Abrams, thats way to much lens flare on these newer science fiction movies.
 
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Offline BrianHGTopic starter

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All the stars with lens flares are really close, IE in the Milky Way galaxy.
Also, stars seen as red in Hubble show as blue in Webb.  Stars which are red as some in orange in Webb are invisible to Hubble.  See around my yellow arrows where I side-by-side shifted these example shots from the website:

Example 1, Webb seeing through clouds:

Example 2, Hubble red seen as blue in Webb, Hubble cant see Webb's orange:

Example 3, Well...  Which version of this galaxy looks better?  Also, can you see the other galaxies behind the current galaxy?
« Last Edit: July 16, 2022, 08:36:07 pm by BrianHG »
 
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Offline BrianHGTopic starter

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Here is the best I could get by turning up the brightness and contrast on the the Hubble image of the Southern Ring Nebula - there really is no comparison with Webb. There simply is not the detail in the Hubble image as much as you turn the gain up. 

Turn up the Gamma instead of the brightness... Like to around 1.5 or even 2...
You still wont see any details, though it will look a lot brighter.
 

Offline iMo

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  • It's important to try new things..
The most deep space pictures taken by Hubble were with exposition times like several days, or a week, afaik.
Webb did those above ones in tens of minutes. That is a huge difference.
Let us wait on the pictures taken by Webb with 5 days exposition times..
 

Online Gyro

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Yes, a mere 12 minutes exposure for the deep field if I remember the news interview correctly.
Best Regards, Chris
 

Online Gyro

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...
One thing to realise is that Hubble has its 'spectacles' fitted which correct the mirror error (I'm not sure if these perfectly correct the error or not?)...

There looks to be a small area of chromatic aberration, in the top left corner of the Hubble SMACS 0723 image. Pretty amazing that the 'spectacles' worked so well though.


Edit: Even more amazing that the shuttle crew managed to do it in orbit, even if Mike Massimino had to wrench off one of the handles to do it!
« Last Edit: July 16, 2022, 09:48:35 pm by Gyro »
Best Regards, Chris
 

Offline iMo

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One of the Webb's mirrors was hit by a dust particle, but they were able to compensate the error, they wrote..
Hopefully a larger damage up there could be easily repaired by Elon's steel rocket carried his Zeus dog  :D
 

Offline BrianHGTopic starter

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Where to get Webb's source data, filter by filter and how to generate your own images:

No JPEGs, no noise removal, or color scheme by NASA.

Seek to 19:35 and watch this guy cycle through the different color filters of the same nebula.  You will see one where the nebula's gas has disappear and only the stars are visible.  It's like Webb has X-ray vision mode.


« Last Edit: July 17, 2022, 04:25:57 am by BrianHG »
 
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Offline hamster_nz

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Someone please fire JJ Abrams, thats way to much lens flare on these newer science fiction movies.

Page 23 of https://www.stsci.edu/files/live/sites/www/files/home/jwst/documentation/technical-documents/%5C_documents/JWST-STScI-001157.pdf would help him get it right... (details the origins of the defraction spikes)
Gaze not into the abyss, lest you become recognized as an abyss domain expert, and they expect you keep gazing into the damn thing.
 

Offline BrianHGTopic starter

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Webb test photos which were not publicly released for some reason: (I bet we are smart enough here to know why...)


 

Offline Sal Ammoniac

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All the stars with lens flares are really close, IE in the Milky Way galaxy.

What you call lens flare is actually diffraction spikes. The following explains why the diffraction pattern around bright starts looks the way it does.

Complexity is the number-one enemy of high-quality code.
 
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Offline negativ3

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Yea, not bad, my dads DSLR from twenty years ago had ONLY eight megapixels...

The cosmos is utterly beautiful and flabbergasting.
 

Offline BrianHGTopic starter

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JWST captures Jupiter's rings:


 

Offline BrianHGTopic starter

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Webb's latest new images, high res: (It takes a few clicks to zoom all the way in...)
https://www.flickr.com/photos/nasawebbtelescope/albums/72177720301006030/with/52259483705/

Webb's first set of images, high res:
https://www.flickr.com/photos/nasawebbtelescope/albums/72177720300469752
 

Offline BrianHGTopic starter

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All the stars with lens flares are really close, IE in the Milky Way galaxy.

What you call lens flare is actually diffraction spikes. The following explains why the diffraction pattern around bright starts looks the way it does.


I wonder if Webb were to take 2 identical exposures, one slightly rotated from the other.  It might be possible to negate the angle differences of the diffraction-spikes in the 2 images.
 

Offline hamster_nz

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I wonder if Webb were to take 2 identical exposures, one slightly rotated from the other.  It might be possible to negate the angle differences of the diffraction-spikes in the 2 images.

It is possible, but to do a rotation you would have to rotate the whole JWST structure. That would most likely not be a trivial exercise, given the constraints it has to operate under - heat shield to face the sun, antennas pointing to the Earth , need to minimizing vibrations (from reaction wheels), and the current load of propellent is all it will ever have - once that is gone the mission is over.
Gaze not into the abyss, lest you become recognized as an abyss domain expert, and they expect you keep gazing into the damn thing.
 

Offline Peter_O

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If I understand NASA right, JW is new in focussing on the infrared.
So there is a lot more nwq information gained, that might not be transferable into visible pictures.
 


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