Questions tagged [james-webb-space-telescope]

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Is this scaling of JWST halo reasonably correct

After thinking about accurately visualizing the size of the Andromeda galaxy I began to wonder about the halo orbit of the James Webb Space Telescope. Using an estimate of 1.5E6 km for halo width and ...
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How are the occurrence and nature of micrometeoroid impacts on JWST optics identified?

There are been recent news about a larger-than-expected micrometeoroid impact on the James Webb Space Telescope's optics. Apparently this was one of several impacts that have already been observed. ...
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Has the small meteorite that hit Webb done a lot of damage?

I read on the web about Webb: A tiny meteoroid struck the newly deployed James Webb Space Telescope in May, knocking one of its gold-plated mirrors out of alignment but not changing the orbiting ...
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Why not build a swarm of space telescopes?

James Webb Space Telescope (JSWT) has not yet started doing science, yet it's successor LUVOIR is being discussed already. However I am curious; some countries have invested billions of dollars in ...
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How much larger will the "observable by us" universe be when JWST becomes operational?

Right now, using all our various current means of observing, we can "see" a sphere of X diameter around us. Webb will increase that to Y diameter. So our observable volume will increase by ...
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In what measure James Webb Telescope "exceeded expectations"?

It is in all the news that the first images of James Webb Telescope "exceed expectations", but in what features? resolution?
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General process of calculating what a telescope's diffraction spikes would look like?

I was reading this question about the JWST's diffraction spikes, and I was rather surprised by the magnitude of the 4 sets of diffraction spikes. The large hexagonal spike pattern I believe is formed ...
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34 votes
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Why does the alignment evaluation image from JWST look like this?

NASA has just released a telescope alignment evaluation image from JWST for the star HD 84406 2MASS J17554042+6551277. It looks like this: Higher resolution at Wikipedia To my untrained eye, the star ...
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What is "Charged time" in JWST ERS proposals?

In the Early Release Science proposals for the JWST such as this one, there is a "Charged Time" rubric. What is it? What is done during this time?
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6 votes
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How are the aberrations seen in early JWST images corrected?

I found this image on space.com and it can also be found in NASA's JWST blog. This is one step in the process of aligning the 18 mirrors on JWST. A single relatively-isolated star has been selected. ...
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6 votes
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JWST mirrors each can be "positioned in tip, tilt, piston, horizontal & vertical decentering and clocking". What does this mean?

This interesting paper by Robert Warden refers to each mirror segment on JWST as having six actuators providing six degrees of freedom in positioning (plus one more to tweak the curvature). These ...
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JWST First Image With Star 18x - Which image is from which mirror?

The James Webb space telescope first image showing the same star 18 times with the unaligned mirrors is great. How do they tell which image corresponds to which mirror? see Photons Received: Webb Sees ...
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James Webb hot temperature

The warmest part of JWST is still hotter (41 $^\circ$C) than me. What I don't understand is where it became so hot (it's been well over 50 $^\circ$C for a long time), and why the hottest point doesn't ...
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10 votes
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How exactly did JWST take a "selfie" of its own primary mirror, and what is the real purpose of this capability?

CNN's Webb telescope's first test images include an unexpected 'selfie' says only: The mirror selfie was captured by a special lens inside NIRCam that can image the primary mirror rather than what ...
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3 votes
1 answer
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What does the celestial sphere look like in thermal IR?

The Space SE question JWST detector heat load asks ...what is the heat load from the collected radiation of the main mirrors on the detector, and how does that vary depending on what objects or ...
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1 vote
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What is the maximum magnitude that the JWST can safely observe?

Similar to Can JWST be damaged by looking at a bright star?. I'd like to know the brightest magnitude that the James Webb Space Telescope can safely observe without damaging any of its instruments. ...
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2 votes
1 answer
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What exactly is the risk to any JWST instrumentation when looking at objects that are "too bright"?

This answer by pela to question #48317 at one point states The star should be bright, but probably not too bright (like Betelgeuse), since we don't want to burn MIRI off from the beginning A comment ...
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Can JWST be damaged by looking at a bright star?

Can JWST be damaged by looking at a bright star? The Sun as well as particularily bright solar-system objects like Jupiter, Venus or the Moon not meant with this question.
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Why will HD 84406 be chosen as the first target for testing JWST?

HD 84406, is a star approximately 241 light-years away in the constellation of Ursa Major. HD 84406 will be the first star to be imaged by the James Webb Space Telescope in order to test the focus of ...
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3 votes
1 answer
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jwst data analysis pipeline -- how to become proficient

I am attempting to try to obtain some proficiency in reviewing and analyzing jwst data. Toward that end, I have installed python language jdaviz environment and files and jwst python environment and ...
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What is the skypath of JWST?

JWST will be in a 6 month halo orbit around the Sun/Earth L2 point, which is located at the anti-solar point. Internet graphics give conflicting information on whether the skypath is clockwise or ...
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How do JWST and Hubble compare in detecting small bodies in the solar system that are a) white, b) black, c) Arrokoth-like, d) Voyager-like?

Assume the object is small, spherical, and illuminated only by the Sun, and has some apparent motion. The object is either: a) white - reflecting 100% perfectly diffusely (assume low temperature) b) ...
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6 votes
1 answer
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When is JWST's first light?

Is there an official estimate when the first light of the James Webb Space Telescope happens? I keep following the press releases from ESA and NASA, but I cannot recall that I saw any on that topic. ...
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7 votes
2 answers
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Which JWST instrument modes are compatible with observations of the bright trans-Earth planets Mars, Jupiter, and Saturn? Which aren't?

My comment says: ...answers to the Space SE question Can James Webb take pictures of our solar system? In what ways will they differ from/compliment those from Hubble? suggest that at some point JWST ...
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6 votes
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Will the James Webb Space Telescope need re-alignment of primary mirror segments?

I couldn't find an answer to this question. James Webb Space Telescope will align primary mirror segments and secondary mirror in space. Question is whether these will need re-alignment during the ...
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5 votes
2 answers
256 views

Question: By design, JWST cannot observe in the anti-sun direction. Is this due to Gegenschein backscatter?

This question has been reposted from Space Exploration Gegenschein is a faint bright spot in the zodiacal light, centered at the antisolar point. By ESO/Y. Beletsky - ESO, CC BY 4.0, https://commons....
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How clear will the images taken by the JWST be, compared to the rest of the telescopes?

How clear will the James Webb Space Telescope images be compared to other telescopes? I mean mainly for things like: Pluto, Eris, Haumea, Makemake, or Quaoar Ceres, Juno, Vesta or Astraea exoplanet ...
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0 votes
3 answers
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How to fix James Webb space telescope?

(Please excuse my English) The James Webb space telescope(JWST) will be launched in 11 days. I've always wondered, how do we fix the JWST if it breaks? The JWST will be too far away. According to ...
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3 votes
1 answer
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What is the fraction of the time that the JWST could view a short transient event on-demand as a function of position on the celestial sphere?

In this answer to Why does JWST have such a big Blind Spot? I argue that this space telescope primary relationship with time is that it strives to look way back in it and so as long as a given ...
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8 votes
4 answers
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Will the James Webb Space Telescope be visible from earth?

Once the JWST is in orbit around L2, would it be possible to view it using any ground based telescopes? I’m mostly thinking of equipment available to amateurs, since I don’t have a 10m reflector. But ...
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4 votes
0 answers
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What was Webb's "key launch clearance review" about?

Yesterday, the ESA press announcement form July 1st, 2021 was widely spreaded in various science and nerd news channels: “We are thrilled to have passed this important step towards the launch of Webb ...
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2 votes
1 answer
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Were K2-141b and WASP-63b selected as the first two exoplanet atmospheres for JWST to look at during its first year of observations? If so, why?

In The Observatory @Donald.McLean linked to Scientists will peer at first galaxies with James Webb telescope which says in part: The new telescope will augment science performed by Hubble, not ...
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1 vote
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Will JWST have fewer observing sessions of much longer duration compared to Hubble?

In The Observatory @Donald.McLean linked to Scientists will peer at first galaxies with James Webb telescope which says in part: Many of the proposed tasks for the Webb telescope were planned and ...
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2 votes
1 answer
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Would an object placed at L1 be seen in front of the Sun from Earth?

Does anything placed at the Lagrangian point L1 between the Earth and Sun obscure the Sun like a transit of the innermore planets? The James Webb telescope is to be placed at L2, but if it was placed ...
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4 votes
1 answer
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How does NASA's ASTHROS stratospheric telescope compare to its James Webb space telescope?

In Space SE I've asked Would it have been cheaper and faster to put a James Webb-like Space Telescope on a balloon instead of a rocket? I linked there to a few news items: CNET: NASA to send stadium-...
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11 votes
1 answer
479 views

Will James Webb see Population III stars?

I have heard that James Webb will see the first stars that our universe produced. Can I assume that we may see galaxies that are so young that all of the stars in them are population III?
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12 votes
1 answer
216 views

What alternative facilities would be available in the event of JWST being destroyed?

Unfortunately, space launches can and do go wrong. Suppose that after all the delays and budget overruns, the launch of the James Webb Space Telescope fails and the telescope becomes a cloud of very ...
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4 votes
1 answer
350 views

How will microshutter arrays be used in the James Webb and future space telescopes?

Question: How will microshutter arrays be used in the James Webb and future space telescopes? Are they acting as a sort of moving pinhole or slit, or is the pattern more complicated, like a coded ...
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8 votes
1 answer
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Will JWST be as durable as the hubble telescope?

JW Space Telescope is designed for a 5-10 year mission duration. Seeing as Hubble and other space missions have paved the way for JWST for reliability issues, It even has zero friction gyro's with 100+...
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9 votes
1 answer
161 views

What is the projected range of the JWST to be able to detect exoplanet atmospheres?

Yesterday the K2 mission detected transit events of objects passing in front of a number of M dwarfs which could turn out to be rocky planets. If some of these planets host atmospheres, could the JWST ...
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11 votes
2 answers
525 views

What visual artifacts are expected from the JWST?

What visual artifacts should we expect from the images that will be released from the James Webb Space Telescope? Specifically, do we expect 3-pronged diffraction spikes (any preview how they would ...
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11 votes
1 answer
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Could the James Webb Space Telescope detect biosignals on exoplanets?

The James Webb Space Telescope (JWST) which is slated to launch in 2018 will bring us a better view of exoplanets, but will it be sufficient to detect signs of life on at least some of those worlds? ...
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21 votes
2 answers
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Parking a telescope at a Lagrange point: is this a good idea from a debris point of view?

The James Webb space telescope is supposed to be located at the Earth-Sun L2 Lagrange point. Do we expect the region around that point to have a higher concentration of space debris, asteroids, dust,...
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