Questions tagged [space-telescope]

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

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37
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4answers
9k views

Why are we building larger land-based telescopes instead of launching larger ones into space?

This question is a follow-up to Do bigger telescopes equal better results? How much bigger does a ground-based mirror have to be to match what a space-based one can do? I guess I'm asking primarily ...
19
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2answers
787 views

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,...
18
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1answer
539 views

Why does a mirror bent 'like a potato chip' allow space telescopes to be smaller and have a wider field of view?

I was browsing NASA featured items and came across this - Out With the Old, In With the New: Telescope Mirrors Get New Shape Called freeform optics, this emerging mirror technology, brought about ...
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0answers
277 views

Method to determine the amount of reflected starlight necessary for an exoplanet to be visible from a given distance/angle? [closed]

What is the method to determine the amount of reflected starlight necessary for an exoplanet to be visible from a given distance/angle? (Not from occlusion but actually visible on its own.) Further, ...
10
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3answers
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Is the James Webb telescope going to orbit around the earth?

If it’s going to orbit around the earth, what kind of orbit would it be (what distance)? Are there benefits to sending a telescope further away from the earth if it’s just to photograph galaxies and ...
9
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3answers
155 views

Why are telescopes positioned in Lagrange points?

In this Wikipedia article about the list of space telescopes to be launched (which I assume is exhaustive), of the 11 telescopes yet to be launched, 6 will be positioned at the Sun-Earth L2 Lagrange ...
9
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1answer
145 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?
9
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1answer
284 views

What are the next planned space telescopes?

We've had hubble for two decades. Its become the most famous space telescope, and lately Kepler seems to be running for the second place. Are there any more powerful, better telescopes planned for ...
8
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1answer
2k views

Theoretically, what is the biggest optical telescope that may exist?

Recently, I read yet another news about E-ELT. It will have 39.3-metre-diameter segmented primary mirror. And I was interested in the next question: Theoretically, what size of the primary mirror (...
8
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1answer
122 views

What is the gravitational lensing focal distance of a white dwarf star?

I tried looking this up, but I couldn't find any formula on gravitational lensing distance. I know that our Sun's is about 550 AU, though further distances work too, as it's not a single focus due ...
8
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1answer
319 views

Is there a cosmic, rather than technological, upper limit to what a telescope can resolve?

Space radio interferometers could have a baseline of millions of kilometers, but is there a point where a larger baseline doesn't improve the resolution anymore because the photons observed are ...
7
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4answers
404 views

Where exactly is the modification that first corrected the spherical aberration in Hubble's primary mirror?

The April 2015 CBS News article How NASA fixed Hubble's flawed vision - and reputation describes the modification taken to the Hubble Space Telescopes by the Space Shuttle that was used to correct for ...
7
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1answer
340 views

How could a 20 inch space telescope “be able to make out Earth-size planets” orbiting alpha Centari?

The NY Times article Telescope to Seek Earthlike Planet in Alpha Centauri System describes a proposed effort to put a telescope into orbit fairly quickly with a narrowly defined purpose - to look for ...
7
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2answers
177 views

Can the Gaia telescope detect small temporarily captured asteroids near its Lagrange orbit?

The Gaia space telescope is in a Lissajous orbit around the Sun-Earth Lagrange point 2. The orbit period is about 180 days and the size of the orbit is 263,000 x 707,000 x 370,000 km. It has been ...
7
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2answers
122 views

Could a space radio telescope fill multiple purposes?

Dream for a while and imagine that there will be a flagship+ mission within a decade to put a large radio telescope in space: What kind of different tasks could the same radio equipment feasibly be ...
6
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2answers
587 views

Are space telescopes completely out of the earth's atmosphere?

Is the Hubble Space Telescope, and every other space telescope for that matter, completely outside the Earths atmosphere?
6
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4answers
349 views

Why not use only one support vane for the secondary mirror, to avoid multiple diffraction spikes?

Each vane holding the secondary mirror in front of the primary causes a diffraction spike. Couldn't the secondary mirror be held with only one vane? If stability is the issue, couldn't it be ...
6
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1answer
2k views

How to calculate the limiting magnitude of Hubble?

I've found various sources on the web stating that the limiting apparent magnitude of the Hubble Space Telescope is about 31 or 31.5. Wikipedia lists that here and it has a cite to a pdf about it. ...
6
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1answer
128 views

Telescope in Sun's gravity lens focus - pointing, gain, distortions

A telescope located in the gravitational focus of the Sun can use the Sun as a magnifying lens. The focus begins 550 AU away, but maybe a 700 or 1000 AU distance is needed to get rid of disturbances ...
6
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0answers
96 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 ...
5
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1answer
160 views

Which space telescope is the most distant?

From the earth, and from the sun. Only interested in active, operational ones.
5
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2answers
277 views

How is the cost of JWST distributed on different parts of development and operations?

The James Webb Space Telescope costs nearly 9 billion dollar. What parts of this project cost how much? I suppose that almost every component has to be developed and is not available to buy off the ...
5
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1answer
151 views

Can ground based telescopes use a starshade in space?

1) Could a starshade in orbit be used by ground based telescopes? If so, what kind of orbit should it have? 2) Could the same starshade be used by two different space telescopes, or does the ...
5
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1answer
77 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 ...
4
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2answers
418 views

Questions about convolving/deconvolving with a PSF

A point spread function (PSF) has many different uses. Consider for instance the following quote: To extract the maximum information out of an observation, even the smallest details of the ...
4
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2answers
82 views

What's still needed before we can observe orbits of exomoons thereby weighing exoplanets?

Comments below this answer to How do we weigh a planet? point out that we currently cannot (or at least have not) detect moons around exoplanets, much less measure the sizes and periods of their ...
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1answer
184 views

Is there an IRAM satellite that measures thermal radiation at 250 GHz, or was this a ground-based instrument?

The Nature Research Letter A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation (also here and here) says about half-way through: We now reassess Eris’ surface ...
4
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1answer
36 views

Why is LUVOIR actively heated?

From the Wikipedia page about LUVOIR design: To enable the extreme wavefront stability needed for coronagraphic observations of Earth-like exoplanets, the LUVOIR design incorporates three ...
4
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1answer
167 views

Could spy satellites use laser guide stars (for adaptive optics)?

Are sodium lasers useful for Earth observing space telescopes/spy satellites?
4
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1answer
178 views

How would a small TCO (temporarily captured orbiter) or other natural Earth satellite most likely be detected?

A sentence from the abstract of The population of natural Earth satellites states: At any given time there should be at least one NES of 1-meter diameter orbiting the Earth. The average temporarily-...
4
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1answer
145 views

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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How was astronomical data meant to be handled on HST precursors?

The first drafts for a large space telescope such as Hubble were made in the 60's, and the idea of a space observatory originated long before that. From Wikipedia: In 1968, NASA developed firm ...
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4answers
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Is it plausible to use other stars for the proposed FOCAL mission instead of the Sun?

For some time, the far-reaching and speculative idea of using the Sun as a gravitational lens has been floating around. See this and this. This would require sending a spacecraft about ~550 AU of a ...
3
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4answers
889 views

Is it practical to build a giant telescope in Moon? (Considering the fact that the atmosphere of moon is very rare)

China's FAST (Five-hundred-meter Aperture Spherical radio Telescope) is the largest radio telescope in the world.(This is huge!!!) As we all know Space Telescopes are better than Earth-Based ...
3
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4answers
265 views

Would space-based telescopes need to remain in the shadow of Earth to avoid light interference from the sun?

So I am thinking about orbiting telescopes tonight and I was thinking that it would probably be beneficial to keep them in the shadow of the Earth or some other space body to avoid light interference. ...
3
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2answers
115 views

What would be the obstacles to building a 6.5km space telescope besides cost?

In the comments of another question on this Stack Exchange site, I talk with another user about the possibility of building an optical space telescope with a 6.5 km aperture. Obviously, this is much ...
3
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1answer
145 views

What are IRAS sources?

Do IRAS sources refer to star forming regions? I searched google and I came to know that it stands for IR astronomical satellite.But what do they search for? Please help me
3
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1answer
123 views

Why didn't we see those campfires on the Sun until now?

What is it about its optics and instrumentation (aperture, sensors, filters), being in space and distance from the Sun on 30 May 2020 that allowed Solar Orbiter's HRIEUV telescope to see something ...
3
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1answer
113 views

What does “forward facing” mean for space telescopes?

I just noticed this announcement from the K2 mission that the field observed for Campaign 16 of the K2 mission would be changed so that the telescope would be "forward facing", saying that "observing ...
3
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1answer
146 views

How are space telescopes stabilised to a perfect standstill?

I assume that for space telescopes to get good images, they must be put in perfect standstill, as even the slightest deviation in the viewing angle is amplified by the distance of observed objects, ...
3
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1answer
139 views

Pictures of galaxies, nebulae: which way is up?

We are used to viewing pictures of the Earth and the planets with their North Pole pointing towards the upper portion of the photo. But when a space telescope snaps photos of cosmic entities, do they ...
3
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1answer
107 views

Maximum distance for earth eclipse

First of all sorry if this question was already asked, but I made a small search here and on google and I couldn't find any answer, so.. Here I am. I was reading NASA's webpage about the Webb ...
3
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1answer
559 views

What are the differences between TESS and PLATO exoplanet telescopes?

Within a year now it has been decided to launch TESS in 2017 and PLATO in 2024, space telecopes of NASA and ESA. They seem to have very similar science goals, both searching for transiting Earth sized ...
3
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0answers
24 views

Understanding WISE acronyms

I've enoucntered many acronyms related between them, like AllWISE, WISE, NEOWISE, CatWISE, WISEA, WISEAR, WISEAF, WISEU, WISEP, WISEPA, WISEPC, WISEF, WISEPF, WISER, WISEWF, WISET, WISETF, WISENF... ...
2
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1answer
83 views

Can the WISE telescope detect black holes?

Black holes are hot, aren't they? With its infrared scan, could the WISE telescope also detect a black hole? The hypothetical planet beyond the Kuiper belt could actually be a primordial black hole. ...
2
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1answer
90 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 ...
2
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1answer
100 views

Why would a tidally-locked rocky planet have a first-order spherical harmonic surface temperature distribution?

The new Letter to Nature Absence of a thick atmosphere on the terrestrial exoplanet LHS 3844b (also ArXiv) analyzes the thermal infrared light curve from the system (about 4.5 to 5.5 um). The planet ...
2
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1answer
69 views

What measure should I use to help optimise the design of a telescope in a cubesat?

I have started a project in Melbourne, Australia called nanosat eye in the sky to put a telescope in a cubesat and put it in LEO. The idea is then to add the telescope to itelescope. I need to learn ...
2
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1answer
52 views

Where can I find source data for the graph of metric expansion over time, as shown in this ESA web page?

This web page from ESA/Hubble, shows the size of the universe over time. (I know that "size of the universe" is a gross simplification and open to multiple definitions and ambiguity, but this kind of ...
2
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1answer
62 views

How might WFIRST help us better understand dark energy?

In the video linked in the Space.com article What Would It Mean for Astronomers If the WFIRST Space Telescope Is Killed?, (available in YouTube as WFIRST: The Best of Both Worlds) after ...