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Questions tagged [space-telescope]

Questions regarding telescopes in orbit around Earth, such as the Hubble Space Telescope.

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Is there any astronomical phenomenon such that its movement can be perceived in real time?

Note: I think I could make this question more interesting by asking, "What is the phenomenon at greatest distance from Earth such that its movement can be perceived in real time?" My ...
releseabe's user avatar
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How to find the minimum range at which some imaging payload/instrument can produce a clear image?

JWST's NIRCam can image deep sky objects so clearly. However if we notice the images of planets like Mars, Saturn or Saturn's's Moon-Titan, they don't appear to be much clear. Hence considering the ...
Dhruv Nayak's user avatar
18 votes
3 answers
6k views

Why don't they put more spare gyroscopes in expensive space telescopes?

I could be forgetting some, but every space telescope I can think of that has died, has died because it ran out of spare gyroscopes. The Saturn Orbiter ran out of fuel, but it wasn't a space telescope....
Miss_Understands's user avatar
3 votes
1 answer
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What is DESI's spatial resolution?

I'm using data from the Dark Energy Spectroscopic Instrument (DESI), and I need to check if its beam coincides with coordinates I've collected for objects in GALEX. From the Fermilab conference ...
Jim421616's user avatar
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How hard or soft is the Hubble's "science floor" due to atmospheric torque? Do some kinds of observations have lower floors than others?

After 04:58 in Scott Manley's How Failed Gyros Are Making Hubble's Life Harder: And while the telescope is floating in space, it is still subject to small forces which can adjust its orientation. ...
uhoh's user avatar
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What is the "handful of observations of close fast moving objects that (Hubble) can't actually track anymore" due to the new one-gyro operation?

After 13:49 in Scott Manley's How Failed Gyros Are Making Hubble's Life Harder: And so with all these systems working together, the telescope can still point at the target and still do top quality ...
uhoh's user avatar
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5 votes
3 answers
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Difference in field of view between JWST and Euclid

I was watching this video about the Euclid telescope. At the 8 minute mark he compares the field of vide of Euclid with that of the JWST, showing that the Euclid field of view is much larger. While I ...
Erontado's user avatar
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6 votes
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What was the exposure duration for the Euclid images released on May 23, 2024?

The Euclid space telescope, a mission by the European Space Agency to map the geometry of the dark universe, released its first set of images on May 23, 2024. What was the total exposure time or ...
Dvid's user avatar
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Why does there appear to be a straight line of red stars in this image of the Large Magellanic Cloud?

In this image of the Large Magellanic Cloud from the Spitzer space telescope, there's a straight line of red stars in the bottom right corner (much easier to see if you go to the link and open the ...
llama's user avatar
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11 votes
2 answers
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Worthwhile to put a telescope on the far side of the Sun?

Are there any plans to place a telescope satellites on the far side of the Sun at the L3 Lagrange point? I think it would be useful for a number of reasons. It would cover our blind spot for incoming ...
KDP's user avatar
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At the intersection of engineering and astronomy in its structure as a scientific discipline

Astronomy is the comprehensive study of what lies beyond the Earth. Modern astronomy (I relied on classifications from here and here) is divided into a large sections (astrophysics, astrogeology, ...
ayr's user avatar
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Did anything happen to "hubble-class" telescopes military gifted to NASA in 2012?

I stumbled onto this news article from 2012 discussing NRO (national reconnaissance office) giving its surplus unlaunched spy satellites over to NASA (with a lot of caveats) It's been 11 years since ...
NooneAtAll3's user avatar
1 vote
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Space-based radio telescope array

I’m wondering about the abilities of a technology: You may have heard of the Square Kilometer Array. The array is focused by adjusting the timing of the individual antennas. Q: Could this array be ...
Joe D's user avatar
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What kind of telescope would be needed to image a 10m dim object 1 million km away?

There's a 10m diameter object 1 million km away from you, stationary with respect to you. The object is dim: it is at 3K and is not reflecting any light towards you. So you have to pick it out by the ...
causative's user avatar
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2 answers
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Formation of spacecraft instrumentation [closed]

List of spacecraft instruments are selected to meet a mission's science goals. Let's take New Horizons as an example and study the composition of Pluto's atmosphere, the shape and geological ...
ayr's user avatar
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How (the heck) does an astronomical Celescope work? And how did it get its name?

Here's an exceprt from the recent question The claim may refer to the band labeled U4 in the Celescope Catalog of Ultraviolet Stellar Observations, which refers to a filter with a spectral response ...
uhoh's user avatar
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How will China's Xuntian space telescope use its Terahertz capability? THz Spectroscopy? Imaging? Something else?

An Update on the Chinese Space Station Telescope Project Hu Zhan, National Astronomical Observatories, CAS, KIAA, Peking University, On behalf of the CSST Team, ISSI-BJ Workshop: Weak gravitational ...
uhoh's user avatar
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11 votes
1 answer
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Did this satellite streak past the Hubble Space Telescope so close that it was out of focus? If so, how close was it?

The new Nature Astronomy paper The impact of satellite trails on Hubble Space Telescope observations (Kruk et al. 2023) describes an AI-based object classification method used to find satellite trails ...
uhoh's user avatar
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How would the "Fluidic Telescope (FLUTE)" next generation telescope make and control a smooth, correct concave optical surface figure in microgravity?

The January 10, 2023 NASA Ames Research Center news item Fluidic Telescope (FLUTE): Enabling the Next Generation of Large Space Observatories discusses a proposed project to study the feasibility of a ...
uhoh's user avatar
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16 votes
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Is there enough data in light coming from distant exoplanets for Earth-orbiting telescopes to take a high-resolution photo of it?

NASA’s James Webb Space Telescope has taken very blurry "photos" of exoplanets around distant stars, such as the exoplanet HIP 65426 b, in different bands of infrared light: My question is, ...
user3163495's user avatar
7 votes
1 answer
1k views

How does the James Webb Space Telescope achieve a focal length of 131.4m?

How does the James Webb Space Telescope achieve a focal length of 131.4m ?
Sebastyen Laroche's user avatar
13 votes
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Has NASA released any JWST images of Trappist-1? If not, why?

According to JWST weekly schedules (found here), the Trappist-1 system was among the telescope's targets during early July. The only JWST image of an exoplanet in the Trappist-1 system that I've ...
William's user avatar
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5 votes
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How often and for what reasons does Hubble use two different instruments at the same time?

A comment under this answer to ** links to Hubblesite.org's Hubble Shoots the Moon The image, its description and credits are shown below. As explained, the purpose of the observation was to record a ...
uhoh's user avatar
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3 votes
1 answer
177 views

Does an umbrella reflector telescope exist?

I searched for use of an umbrella mechanism for a reflecting telescope but have not found anything. I was imagining that use of enough actuators on enough umbrella arms would allow fine tuning an ...
jeremy_rutman's user avatar
4 votes
1 answer
221 views

How did this artefact end up in the SIMBAD sky map?

I was randomly looking through the SIMBAD sky map when I came across this artefact. It looks like the projection of a telescopes secondary mirror mount to me but I am wondering how that would end up ...
Liberty's user avatar
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7 votes
2 answers
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Which (if any) space telescope would have worked longer if it hadn't simply run out of helium?

In this answer to Why is the hot part of Webb's MIRI cryocooler in the 300K area? and comments below discusses the helium refrigerator used for cooling JWST's Mid-Infrared Instrument or MIRI. A ...
uhoh's user avatar
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4 votes
1 answer
113 views

Why is infrared the ideal band to detect the earliest and most-redshifted galaxies? [duplicate]

Was infrared chosen for the James Webb Space Telescope's mission to detect the most-redshifted galaxies and stars in the universe because most detectable galactic radiation emits most strongly in the ...
Rich McDaniel's user avatar
14 votes
1 answer
1k views

Why use a large separate starshade instead of an occulting disk?

The New Worlds Mission proposal has a large occulter on a different spacecraft from the space telescope to block glare from a star to reveal its planets. What is its advantage compared to a disk on an ...
Gnubie's user avatar
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How does JWST position itself to see and resolve an exact target?

Let's say the James Webb Space Telescope wants to move from observing the Andromeda galaxy millions of light years away to looking at the Trappist-1e planet some dozens of light years away, what ...
joeyfb's user avatar
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0 votes
2 answers
243 views

What percentage of visible stars will JWST be able to survey over the next 10 years?

The James Webb telescope is projected to stay operational over the next 10 years. During this time, what percentage of the visible universe/stars will it be able to survey? Of course, technically the ...
JonathanReez's user avatar
4 votes
0 answers
203 views

What is the large dim feature near the center of the first James Webb image (of SMACS 0723)?

I was intrigued by the large dim feature (highlighted below) in the center of the first James Webb image of SMACS 0723. Is anything known about it?
MVTC's user avatar
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2 answers
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Orientation of the optical telescope assembly in the Hubble Space Telescope

What is the orientation of the optical telescope assembly with respect to the direction of motion of the Hubble Space Telescope? If it happens to be in the direction of motion, does the primary mirror ...
JKrsl's user avatar
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3 votes
1 answer
221 views

How did NASA choose "James Webb" as the name of the telescope?

How did NASA decide to name the telescope "James Webb" and not some other name like Copernicus or Ptolemy? The wiki page mentions controversy over the name in the past couple of years but ...
JonathanReez's user avatar
2 votes
2 answers
186 views

What is stopping Event Horizon Telescope the size of the Earth’s orbit?

There is a proposal to include a radio sensor in a telescope going to the Sun-Earth L2, getting 120x improvement in angular resolution to EHT. Knowing nothing about interferometry, it seems pretty ...
Ahmbak's user avatar
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8 votes
1 answer
245 views

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. ...
Roger Wood's user avatar
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2 votes
1 answer
235 views

How far above the galactic plane would a telescope array need to be in order to image the whole galaxy?

I hope this isn't a stupid question, but Google searches are turning up nothing relevant. I was just thinking about how it's difficult for us to determine the true shape and composition of the Milky ...
Curious Layman's user avatar
2 votes
1 answer
80 views

What do the letters WHL and LS stand for in the description and name of Earendel star, and other distant objects?

Earendel star's official name includes the abbreviations WHL and LS, as do some other very far-off objects.... What do they stand for?
Kurt Hikes's user avatar
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4 votes
1 answer
194 views

How exactly does SPHEREx implement 96 spectral bands with a linear variable filter across its focal plane?

JPL's mission page for SPHEREx says: The mission will create a map of the entire sky in 96 different color bands, far exceeding the color resolution of previous all-sky maps. Wikipedia's SPHEREx ...
uhoh's user avatar
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8 votes
3 answers
324 views

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?
Colim's user avatar
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4 votes
2 answers
637 views

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?
usernumber's user avatar
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7 votes
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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 ...
ZBwith3ARMs's user avatar
20 votes
2 answers
9k views

How many pixels could an image of Proxima b taken by James Webb have?

I know it's very difficult for the James Webb Space Telescope to image the exoplanet Proxima b without an external coronograph (I have been told by NASA scientists that they don't know yet whether ...
James's user avatar
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3 votes
1 answer
184 views

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 ...
uhoh's user avatar
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2 votes
1 answer
1k views

What is the smallest (brightest) 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. ...
WarpPrime's user avatar
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6 votes
2 answers
193 views

Does a star shaped mirror present problems either optically, or in signal processing over a more nearly circular mirror?

Pure speculation about a future replacement for the JWST that I almost certainly won't live to see. The JWST's mirror (and then some) would fit unfolded and flat into the Starship's 8m diameter ...
Buk's user avatar
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2 votes
1 answer
117 views

How does IXPE measure polarization, and why does it have three identical X-ray telescopes?

From The Observatory: Anyone who missed any of the AAS 239 press conferences can see them on the AAS Press Office's YouTube channel! Here's the full program. From there I found the Monday, January ...
uhoh's user avatar
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8 votes
2 answers
1k views

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 ...
uhoh's user avatar
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6 votes
2 answers
196 views

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 ...
akostadinov's user avatar
1 vote
1 answer
66 views

How many asteroids were discovered via GAIA? Is there a list?

The ESA Science & Technology video Gaia's asteroid discoveries shows trajectories for hundreds of asteroids that were seen by GAIA, but as far as I can deduce from the extensive notes there, only ...
uhoh's user avatar
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2 votes
1 answer
126 views

Are there any space-based observatories that use interferometry?

Ground-based interferometers such as ALMA have enabled many discoveries. It seems like sending a fleet of small telescopes would be feasible (smaller telescopes are easier to send into space than ...
usernumber's user avatar
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