On Monday, 11 July 2022 at 19:04:49 UTC-4, StarDust wrote:
https://www.bbc.com/news/science-environment-62122859
Deepest ever!
Stupid CNN reporter thinks the curves are "motion." Do they even READ
the NASA info???
https://www.cnn.com/2022/07/11/world/james-webb-space-telescope-first-image-scn/index.html
It's a gravitational effect; the astronomical equivalent of a zoom lens for a telescope.<<The cluster itself isn't actually that far away - "only" about 4.6 billion light-years in the distance. But the great mass of this cluster has bent and magnified the light of objects that are much, much further away.
https://www.bbc.com/news/science-environment-62122859
Deepest ever!
Stupid CNN reporter thinks the curves are "motion." Do they even READ
the NASA info???
On Monday, July 11, 2022 at 8:29:33 PM UTC-6, RichA wrote:
Stupid CNN reporter thinks the curves are "motion." Do they even READI see the article has been corrected. The galaxies affected by the lensing, in at least one part of the image, do seem to be elongated around a common center, so it does kind of resemble how stars can be streaked by the Earth's rotation.
the NASA info???
But the JWST is not _on_ Earth.
What puzzles me is the diffraction spikes.
That they make six-pointed stars makes sense, what with all the hexagonal mirrors. But there are also two smaller spikes, at a right angle to one of the
larger pairs. No doubt there's something in the telescope's construction responsible for this, like the arms holding the secondary, but it's something I
wasn't expecting.
John Savard
What puzzles me is the diffraction spikes.
That they make six-pointed stars makes sense, what with all the hexagonal mirrors. But there are also two smaller spikes, at a right angle to one of the
larger pairs. No doubt there's something in the telescope's construction responsible for this, like the arms holding the secondary, but it's something I
wasn't expecting.
With a shape like that, had I been thinking about what the diffraction pattern of the
telescope would look like, I would have been expecting _twelve_ diffraction spikes
in two groups of six rather than just six plus two. Perhaps a closer look will turn up
more tiny little diffraction spikes.
On Monday, July 11, 2022 at 11:36:15 PM UTC-4, Quadibloc wrote:
What puzzles me is the diffraction spikes.
That they make six-pointed stars makes sense, what with all the hexagonal mirrors. But there are also two smaller spikes, at a right angle to one of the
larger pairs. No doubt there's something in the telescope's construction responsible for this, like the arms holding the secondary, but it's something I
wasn't expecting.
One of the arms of the "spider" does not line up with any of the edges of the mirror
segments, so you get those spikes seen horizontally in the picture.
On Tuesday, July 12, 2022 at 11:54:58 AM UTC-6, Quadibloc wrote:
With a shape like that, had I been thinking about what the diffraction pattern of theI've just looked at the full-resolution version of that image, with additional zoom,
telescope would look like, I would have been expecting _twelve_ diffraction spikes
in two groups of six rather than just six plus two. Perhaps a closer look will turn up
more tiny little diffraction spikes.
on my computer. Yes, there are more diffraction spikes. Less bright stars show
a six-plus-six spike pattern; the bright ones, where two horizontal spikes are prominent,
also show not only those four additional spikes, but some at in-between positions that
do not appear to be at angles that are exactly halfway. And then still other spikes,
making a total of 48 spikes for the brightest stars in the image!
John Savard
On Monday, July 11, 2022 at 11:36:15 PM UTC-4, Quadibloc wrote:
What puzzles me is the diffraction spikes.
That they make six-pointed stars makes sense, what with all the hexagonal mirrors. But there are also two smaller spikes, at a right angle to one of the
larger pairs. No doubt there's something in the telescope's construction responsible for this, like the arms holding the secondary, but it's something I
wasn't expecting.
One of the arms of the "spider" does not line up with any of the edges of the mirror segments, so you get those spikes seen horizontally in the picture.
On Tuesday, July 12, 2022 at 11:54:58 AM UTC-6, Quadibloc wrote:
With a shape like that, had I been thinking about what the diffraction pattern of the
telescope would look like, I would have been expecting _twelve_ diffraction spikes
in two groups of six rather than just six plus two. Perhaps a closer look will turn up
more tiny little diffraction spikes.
I've just looked at the full-resolution version of that image, with additional zoom,
on my computer. Yes, there are more diffraction spikes. Less bright stars show >a six-plus-six spike pattern; the bright ones, where two horizontal spikes are prominent,
also show not only those four additional spikes, but some at in-between positions that
do not appear to be at angles that are exactly halfway. And then still other spikes,
making a total of 48 spikes for the brightest stars in the image!
The pattern changes considerably with the filter that is used, as it
is wavelength dependent.
On Tuesday, July 12, 2022 at 11:12:45 PM UTC-6, Chris L Peterson wrote:
The pattern changes considerably with the filter that is used, as itI did pick that document up from a link in the article W linked to.
is wavelength dependent.
And I noticed that the diffraction spikes varied in color in the images,
but I didn't read the paper closely enough to find out why the diffraction pattern would be wavelength-dependent.
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