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  • Webb telescope diffraction, responsible for some of the "detail" it sho

    From RichA@21:1/5 to All on Mon Aug 21 17:05:33 2023
    I'm beginning to wonder. The Ring shot here shows considerable fine-frequency detail, but look the the bright star, the diffraction effects. I'm wondering if some of that isn't rubbing off on the nebula details?

    https://esawebb.org/images/weic2320b/

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  • From Chris L Peterson@21:1/5 to All on Mon Aug 21 18:34:16 2023
    On Mon, 21 Aug 2023 17:05:33 -0700 (PDT), RichA <rander3128@gmail.com>
    wrote:

    I'm beginning to wonder. The Ring shot here shows considerable fine-frequency detail, but look the the bright star, the diffraction effects. I'm wondering if some of that isn't rubbing off on the nebula details?

    https://esawebb.org/images/weic2320b/

    No. We see the diffraction around the star, which is orders of
    magnitude brighter than any of the ring structure. Diffraction from
    ring structure well below the noise level.

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  • From AB@21:1/5 to RichA on Tue Aug 22 03:54:00 2023
    On 8/21/23 8:05 PM, RichA wrote:
    I'm beginning to wonder. The Ring shot here shows considerable fine-frequency detail, but look the the bright star, the diffraction effects. I'm wondering if some of that isn't rubbing off on the nebula details?

    https://esawebb.org/images/weic2320b/

    My oh my, getting a little picky, aren't we? What about all of the
    wonderful astronomical objects that it has been resolving like never
    before?

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  • From Martin Brown@21:1/5 to Chris L Peterson on Wed Aug 23 12:54:47 2023
    On 22/08/2023 01:34, Chris L Peterson wrote:
    On Mon, 21 Aug 2023 17:05:33 -0700 (PDT), RichA
    <rander3128@gmail.com> wrote:

    I'm beginning to wonder. The Ring shot here shows considerable
    fine-frequency detail, but look the the bright star, the
    diffraction effects. I'm wondering if some of that isn't rubbing
    off on the nebula details?

    https://esawebb.org/images/weic2320b/

    No. We see the diffraction around the star, which is orders of
    magnitude brighter than any of the ring structure. Diffraction from
    ring structure well below the noise level.

    That is true enough but I think that there may be some very slight amplification of linear features that are aligned with the main
    diffraction spikes (and attenuation of those aligned with the nulls).

    It is way more subtle than adding features though. Incidentally the
    website rendering of the image has terrible contrast and is cropped if
    you copy the image and paste into your favourite editor there is a lot
    more detail further out that you can see quite clearly.

    To my eyes at least the linear structures appear slightly more well
    defined at PA 0, 60, 120 and a but weaker at PA 30, 90, 150

    The linear structures also match what you might expect a strong solar
    wind to look like and you can see the outer shell(s) on the full image.

    --
    Martin Brown

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  • From RichA@21:1/5 to All on Wed Aug 23 16:04:43 2023
    On Tuesday, 22 August 2023 at 03:54:04 UTC-4, AB wrote:
    On 8/21/23 8:05 PM, RichA wrote:
    I'm beginning to wonder. The Ring shot here shows considerable fine-frequency detail, but look the the bright star, the diffraction effects. I'm wondering if some of that isn't rubbing off on the nebula details?

    https://esawebb.org/images/weic2320b/
    My oh my, getting a little picky, aren't we? What about all of the
    wonderful astronomical objects that it has been resolving like never
    before?

    No argument on that, but digital photography, in the early years was plagued by diffraction effects, (artifacts) that were at small-scales sometimes mistaken for
    detail. The Webb with its segmented mirror, unlike Hubble, does show considerable diffraction effects.

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  • From Chris L Peterson@21:1/5 to '''newspam'''@nonad.co.uk on Wed Aug 23 18:12:30 2023
    On Wed, 23 Aug 2023 12:54:47 +0100, Martin Brown
    <'''newspam'''@nonad.co.uk> wrote:

    On 22/08/2023 01:34, Chris L Peterson wrote:
    On Mon, 21 Aug 2023 17:05:33 -0700 (PDT), RichA
    <rander3128@gmail.com> wrote:

    I'm beginning to wonder. The Ring shot here shows considerable
    fine-frequency detail, but look the the bright star, the
    diffraction effects. I'm wondering if some of that isn't rubbing
    off on the nebula details?

    https://esawebb.org/images/weic2320b/

    No. We see the diffraction around the star, which is orders of
    magnitude brighter than any of the ring structure. Diffraction from
    ring structure well below the noise level.

    That is true enough but I think that there may be some very slight >amplification of linear features that are aligned with the main
    diffraction spikes (and attenuation of those aligned with the nulls).

    It is way more subtle than adding features though. Incidentally the
    website rendering of the image has terrible contrast and is cropped if
    you copy the image and paste into your favourite editor there is a lot
    more detail further out that you can see quite clearly.

    To my eyes at least the linear structures appear slightly more well
    defined at PA 0, 60, 120 and a but weaker at PA 30, 90, 150

    Look at the Fourier transform of the image, and you very strongly see
    the diffraction structure at those angles. When I mask out the 8
    brightest stars and their diffraction spikes, the FT looks absolutely structureless except for the contribution of the image edges.

    I don't think there is any visible structure introduced by diffraction
    in this image except around bright stars.

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