[Unregistered User 8]

Yes! And it is NOT a mirrorless camera!

Not mirrorless, no, but there ain't a flippy screen in the mix though. For $10 billion, I would have expected at least one.
Maybe the James Webb Mark II........

Seriously, a wonderful achievement, and looking forward to seeing the images it takes.

[AgentL]

Not as good as the Sony cameras.

[simsburyphoto]

Not as good as the Sony cameras.

If all goes according to plan this could be one of mankind's greatest scientific achievements.

[Time Traveller]

As I understand it, as light waves travel over extremely long distances (which takes an extremely long time, therefore what we see today happened way way in the past) they eventually shift towards longer waves (IR is longer waves), so called redshift.
This new imaging system will be able to see larger IR waves than Hubble. This is why they needed the fancy huge folding mirror, because the light waves themselves are literally bigger. This will allow the new telescope to see further back in time, something a Time Traveller should appreciate!
Here's an article that touches on that stuff.

Thanks for sharing! It would have been nice with some ordinary footage of galaxies, planets and objects in the visible light spectrum.

[photoptimist]

Not mirrorless, no, but there ain't a flippy screen in the mix though. For $10 billion, I would have expected at least one.
Maybe the James Webb Mark II........

Seriously, a wonderful achievement, and looking forward to seeing the images it takes.

Actually, there's not "a" flippy mirror, there's several in the James Webb telescope.

The main mirror of the telescope is the biggest flippy mirror ever! It's got two large segments (about 4 feet x 12 feet) that flip into place to make the main mirror. (OK, they only do this once during the set-up of the telescope, but still, it does flip.)

Then there's a steering mirror in the telescope that can flip very slightly in both x and y axes up to 100 times a second to help stabilize the beam.

Finally, the instruments themselves have some flippy mirrors to control where the main imaging beam of the telescope is going.

JWST is a DSLR!

[wadge22]

It would have been nice with some ordinary footage of galaxies, planets and objects in the visible light spectrum.

That's true. I would have to guess that there will still be images we will get to view, and chances are they will be amazing.
My mother has an IR converted DSLR she uses, and of course the images it produces are visible to us when she prints them or displays them on a screen. Some are very cool. The IR camera is sort of a translator from wavelengths we don't see to ones we can. I don't know for sure that's how the Webb will work (I believe scientific discovery is the main thrust of the mission, with inspirational images a built in bonus), but I would assume so, too.


For now, we can still enjoy some of the stellar shots from Hubble.

[Time Traveller]

For now, we can still enjoy some of the stellar shots from Hubble.

These images of the infinite universe, taken by the Hubble Telescope, make it difficult to believe in the Big Bang theory, that is, that the entire known universe springs from a point smaller than an atom, an expansion of almost nothing to what we today can see around us. There must be an alternative to this theory. It is just a theory. The gravitational waves could have other causes than a 'Big Bang', I think. But that's a different story - and not so much about Pentax cameras (although they are (also?) created from nothing!).

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Last edited by Time Traveller; 12-26-2021 at 12:41 PM.

[yucatanPentax]

It's truly an amazing device and quite an accomplishment. I'm looking forward to new discoveries and revelations about our universe. The physics behind the whole "light decaying toward infrared", to me, is fascinating. I'd not heard of that before the news about the Webb telescope.

[AgentL]

If all goes according to plan this could be one of mankind's greatest scientific achievements.

You're talking about the A7 mk IV, right?

[Digitalis]

It will be interesting to see how the cameras perform with their complex micro shutter mechanisms, that technology could potentially have a market in cameras where very high dynamic ranges are needed to be visualized.

---------- Post added 2021-12-29 at 03:49 PM ----------

JWST is a DSLR

albeit sans interchangeable lenses, unlike the hubble main mirror which launched with rather spectacular spherical errors and the mercy missions flown over to correct for it. JWST won't have that luxury.

[Paul the Sunman]

albeit sans interchangeable lenses, unlike the hubble main mirror which launched with rather spectacular spherical errors and the mercy missions flown over to correct for it. JWST won't have that luxury.

I was at the International Astronomical Union General Assembly in Baltimore in 1988. The meeting was supposed to be a celebration of the Hubble launch, but it had been delayed by the Challenger disaster and Hubble was still sitting on the ground. They had a couple of years to do lots of optical tests, which would have picked up the error in the optics, but didn't have funding to do it. What a total waste. Apart from the excessive costs of in situ repair after launch, the whole debacle ruined some people's lives.

In the end though, Hubble turned out to be a huge success, thanks to clever optical fudging.

Let us hope the JWST commissioning goes much more smoothly.

[yucatanPentax]

Not mirrorless, no, but there ain't a flippy screen in the mix though. For $10 billion, I would have expected at least one.
Maybe the James Webb Mark II........

Seriously, a wonderful achievement, and looking forward to seeing the images it takes.

No flippy screen, but a danged serious WiFi connection!

[Digitalis]

. They had a couple of years to do lots of optical tests, which would have picked up the error in the optics, but didn't have funding to do it. What a total waste.

I'm a stickler for optical quality, I would have found a way to get tests funded. Fortunately for JWST the far and near IR wavelengths are not quite as difficult to collimate as the relatively narrowband UV-Vis- NIR wavelengths that HST does. The shorter the wavelengths of light get the harder it is to make them bend - that is why the Chandra observatory looks the way it does.

[ehrwien]

It's a mirror lens, right? The bokeh must be terrible...

Focal length 131.4 meters, and I guess

"Diameter of primary Mirror: 6.5 m (21.3 ft) approximately
Clear aperture of primary Mirror: 25 m²

means something like 131.4/5.6 = f/23?
What about diffraction, is that more or less of a problem in the infrared spectrum (My guess: less?)? How big is the sensor?

I hope they have something like MLU and there's no shutter shock

Regarding shutter:

Near Infrared Spectrograph (NIRSpec) Instrument Webb/NASA

One unique technology in the NIRSpec that enables it to obtain those 100 simultaneous spectra is a micro-electromechanical system called a "microshutter array." NIRSpec's microshutter cells, each approximately as wide as a human hair, have lids that open and close when a magnetic field is applied. Each cell can be controlled individually, allowing it to be opened or closed to view or block a portion of the sky.

It is this adjustability that allows the instrument to do spectroscopy on so many objects simultaneously. Because the objects NIRSpec will be looking at are so far away and so faint, the instrument needs a way to block out the light of nearer bright objects. Microshutters operate similarly to people squinting to focus on an object by blocking out interfering light. (Read more about NIRSpec's microshutter technology.)

That's cool! Though, magnetic field sounds like solenoid. I hope they found a source for the good white Japanese ones

Mirrors Webb/NASA
A oval mirror, for example, would give images that are elongated in one direction.

Would that result in some J.J. Abrams anamorphic lens-flare like effects?

"Aligning the primary mirror segments as though they are a single large mirror means each mirror is aligned to 1/10,000th the thickness of a human hair. What's even more amazing is that the engineers and scientists working on the Webb telescope literally had to invent how to do this."

I smell a patent infringement coming from Pentax Do we have any data how precise the Pentax IBIS is in "thickness of a human hair" speech?

Aligning the Mirrors on Earth and in Space

Once the telescope is in orbit, Engineers on Earth will need to make corrections to the positioning of the Webb telescope's primary mirror segments to bring them into alignment - ensuring they will produce sharp, focused images.

These corrections are made through a process called wavefront sensing and control, which aligns the mirrors to within tens of nanometers. During this process, a wavefront sensor (NIRCam in this case) measures any imperfections in the alignment of the mirror segments that prevent them from acting like a single, 6.5-meter (21.3-foot) mirror. Engineers will use NIRCam to take 18 out-of-focus images of a star - one from each mirror segment. The engineers then use computer algorithms to determine the overall shape of the primary mirror from those individual images, and to determine how they must move the mirrors to align them.

Can we get that focus system for our cameras? Sounds like Canon's dual pixel af x9?

Infrared Detectors Webb/NASA

Webb has extended the state of the art for infrared detectors by producing arrays that are lower noise, larger format, and longer lasting than their predecessors.

That's just mocking camera manufacturers' marketing bullshit, isn't it?

Each Webb H2RG detector has about 4 million pixels. The mid-infrared detectors have about 1 million pixels each.

Doesn't sound like much. My K-1 has 36 million pixels

It is possible to read the pixels in a Webb detector more than once before resetting them. This provides several benefits. For example, it is possible to average multiple non-destructive reads together to reduce the read noise compared to doing only one read. Another advantage is that by using multiple samples of the same pixel, it is possible to see the "jumps" in signal level that are the tell tale sign that a cosmic ray has disturbed a pixel. Once it is known that a cosmic ray has disturbed a pixel, it is possible in ground based processing to apply a correction to recover much of the scientific value of the affected pixel.

Just amazing how much engineering went into every little bit of this project and I hope it succeeds in delivering imagery for 10 years and more.

[Digitalis]

What about diffraction, is that more or less of a problem in the infrared spectrum (My guess: less?)

Correct... However at f/23 there still will be some diffraction in the deep red/near-infrafred it won't be anywhere near as bad as what we see with our cameras.