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Tomorrow Dec 25th 2021, is a very big day! James Webb Scope is headed out.
- Thread starter JRS
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JSmith
Master Contributor
New Webb Image Captures Clearest View of Neptune’s Rings in Decades - NASA
NASA’s James Webb Space Telescope shows off its capabilities closer to home with its first image of Neptune. Not only has Webb captured the clearest view of this distant planet’s rings in more than 30 years, but its cameras reveal the ice giant in a whole new light.
www.nasa.gov
JSmith
sam_adams
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Uh-oh indeed - can't send up a space shuttle to fix this one.
Slightly dissapointed with this image. I've seen Saturns rings with a 100mm (near toy) telescope sat on my drive in a fairly light polluted location. I'd sort of expected JW to be able to do better.
New Webb Image Captures Clearest View of Neptune’s Rings in Decades - NASA
NASA’s James Webb Space Telescope shows off its capabilities closer to home with its first image of Neptune. Not only has Webb captured the clearest view of this distant planet’s rings in more than 30 years, but its cameras reveal the ice giant in a whole new light.
JSmith
JSmith
Master Contributor
Especially since the Space Shuttle has been retired/decommissioned.
I believe it is to do with this;
JWST has captured an astonishing view of Neptune and its rings
A new image from the James Webb Space Telescope shows eight of Neptune’s moons and four of its rings – two of which haven’t been seen in more than 30 years
JSmith
More the general clarity than colour TBH.Especially since the Space Shuttle has been retired/decommissioned.
I believe it is to do with this;
JWST has captured an astonishing view of Neptune and its rings
A new image from the James Webb Space Telescope shows eight of Neptune’s moons and four of its rings – two of which haven’t been seen in more than 30 yearswww.newscientist.com
JSmith
Perhaps my expectations have been unrealistically raised by TV CGI
Do you know if they provide somewhere an equivalence of color in the images to real wavelengths measured? A sort of table would do the job.
That only works with doppler shifted light where there are relativistic speeds involved. Won't apply to local objects such as Saturn. JW is measuring only in the IR, so that is what we get.
Why do you guys always complicate things when talking physics?
Measured wavelength is measured wavelength. Another things is that knowing that the sources can't produce that wavelength due to its nature, one infers that they are moving and that explains its color anomaly. From that point, one can infer velocity of distant starts by analyzing their color anomaly.By the way, a traffic radar uses the same principle, using microwaves, to measure car speed, which is way below the speed of light, because the bounced wave has a slightly different wavelength.
Anyway, that was not my point.
JW measures IR and a bit of visible, red to us, so it's impossible that we can se any other color from an image taken by it, white of course not. The folks at NASA take the original image and apply a transformation from raw measured wavelengths to visible spectrum. However, the range the JW measures is wider than visible, so it's not a direct relation. Somewhere, there is a rule to convert the frequencies/wavelengths from the JW to visible ones to build this images. I was asking if someone knew about it.
You do realize that Neptune is more than twice the distance away and less than half the size of Saturn, and a heck of a lot less luminous to boot? I was blown away with the clarity of this image, especially from an infrared telescope. The full image of the entire Neptunian system is spectacular.
Martin
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Now, I feel foolish.You do realize that Neptune is more than twice the distance away and less than half the size of Saturn, and a heck of a lot less luminous to boot? I was blown away with the clarity of this image, especially from an infrared telescope. The full image of the entire Nuptunian system is spectacular.
Martin
I saw rings and thought "saturn". I don't think I even knew Neptune had rings.
Saturn's rings are predominantly icy and very reflective, Neptune's contain lots of less reflective dust.
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In general you take the wavelengths of an image like in this case infrared, and filter it so the lower third in wavelengths is rendered in a greyscale, and do the same for the middle third and upper third by wavelength. You then assign red, green and blue to these making them red-scale, green-scale and blue-scale images. And combine them for a visible false color image. The exact percentages of assigned wavelengths and such can vary for other purposes, but this is in general how it is done.Why do you guys always complicate things when talking physics?
By the way, a traffic radar uses the same principle, using microwaves, to measure car speed, which is way below the speed of light, because the bounced wave has a slightly different wavelength.
Anyway, that was not my point.
JW measures IR and a bit of visible, red to us, so it's impossible that we can se any other color from an image taken by it, white of course not. The folks at NASA take the original image and apply a transformation from raw measured wavelengths to visible spectrum. However, the range the JW measures is wider than visible, so it's not a direct relation. Somewhere, there is a rule to convert the frequencies/wavelengths from the JW to visible ones to build this images. I was asking if someone knew about it.
Easy mistake to make at first glance. This images show Neptune's rings very well. Jupiter and Uranus also have rings.
Jupiter:
Uranus:
Martin
Every day is a school day here at ASREasy mistake to make at first glance. This images show Neptune's rings very well. Jupiter and Uranus also have rings.
Jupiter:
Uranus:
Martin
Thanks
Whenever I see nice pictures of something on the universe I tend to think that someone has taken some liberties to translate the original image to the published one. This Neptune one looks more credible than the first ones to me. I don't mean the other are fake, but it's hard to believe the isn't a human touch on them.
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Did someone fool around to make them pretty? I don't know...maybe.Thanks
Whenever I see nice pictures of something on the universe I tend to think that someone has taken some liberties to translate the original image to the published one. This Neptune one looks more credible than the first ones to me. I don't mean the other are fake, but it's hard to believe the isn't a human touch on them.
Another use of false color is investigating paintings for touch ups or fakes. You can use UV or infrared, and you distribute the colors over the range of wavelengths needed to get an image humans can usefully process. It might be a little bit like taking a recording with response to 40 khz. Filter out everything below 20 khz, and then slow what is left by 50% so a human can "hear" what is up there. It is transposed into a 20 khz range we can hear. There of course can never be a one to one correspondence, but it can usefully be used to listen to what is going on ultrasonically. Another example are whale sounds some of which are too low in frequency for us to hear. They are sped up so we can hear them. If they sound hauntingly beautiful it doesn't mean anyone created it to be that way.
