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98 votes

Does it make any scientific sense that a comet coming to crush Earth would appear "sideways" from a telescope and on the sky (from Earth)?

The comet's tail always points away from the Sun. Yes, even when the comet is heading back into the outer solar system. This is because the tail isn't a 'trail' of where the comet has been, like a ...
Ingolifs's user avatar
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40 votes
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Can James Webb take pictures of our solar system? In what ways will they differ from/compliment those from Hubble?

JWST must forever be oriented to remain in the shadow of its own sun shield, so that it remains cool and sensitive to the low temperatures of deep space, limiting what can be observed. Notably, it ...
Wyck's user avatar
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29 votes

Can James Webb take pictures of our solar system? In what ways will they differ from/compliment those from Hubble?

Here's NASA's site with an overview of already approved Solar System science missions for JWST: https://www.stsci.edu/jwst/science-execution/approved-programs/cycle-1-go If you click on the red number ...
LocalFluff's user avatar
28 votes
Accepted

Would a lunar telescope provide a significant improvement over terrestrial based equipment?

As stated, the answer to the question has to be yes, a telescope on the Moon can have significant advantages over a telescope on Earth, because of Earth's atmosphere. That's why we have space ...
Mark Adler's user avatar
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22 votes

Can James Webb take pictures of our solar system? In what ways will they differ from/compliment those from Hubble?

https://jwst.nasa.gov/content/forScientists/faqScientists.html 10. Can Webb observe objects in our Solar System? Yes. Webb is designed to be able to observe solar system objects having an apparent ...
ceejayoz's user avatar
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20 votes
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If we used Hubble, or the James Webb Space Telescope, how good image could we get of the Starman?

The angular resolution of the Hubble and James Webb telescopes are about the same - both are around $0.05$ to $0.1$ arc seconds or about $4 \times 10^{-7}$ radians. If we express the angle $\theta$ in ...
John Rennie's user avatar
18 votes

What's the largest aperture telescope sent beyond the Earth-Moon system?

After looking through various mission articles on Wikipedia, the Mars Reconnaissance Orbiter's HiRISE camera has an aperture of 19.7 inches (50 cm), which Wikipedia claims is "the largest so far of ...
Phiteros's user avatar
  • 5,626
17 votes

If we used Hubble, or the James Webb Space Telescope, how good image could we get of the Starman?

Hubble is one of the few telescopes that could possibly image Starman, as a dot. James Webb will have far more sensitivity. It's a really small space rock in a really big space. You can take a look at ...
PearsonArtPhoto's user avatar
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15 votes
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Is it feasible to paint SpaceX Starlink satellites black so as not to frequently saturate the CCDs of the Large Synoptic Survey Telescope?

In general satellites are not "painted". They are covered in a variety of Multi-Layer Insulation (MLI) blankets with varying optical qualities. I have seen MLI in silver, black, and gold - sometimes ...
Carlos N's user avatar
  • 4,474
15 votes

Does it make any scientific sense that a comet coming to crush Earth would appear "sideways" from a telescope and on the sky (from Earth)?

While those movies probably do it because that's how comets are commonly depicted, it might not be that inaccurate. Remember that the Earth itself is moving around the Sun, so if a comet is heading ...
Pitto's user avatar
  • 1,246
15 votes

Does it make any scientific sense that a comet coming to crush Earth would appear "sideways" from a telescope and on the sky (from Earth)?

If you're the comet, the way to hit Earth is not to head directly for it. That's because Earth is orbiting the sun: you need to aim at where Earth will be, not where it is right now. For example: By ...
Phil Frost's user avatar
  • 1,033
13 votes

Has any ground-based telescope taken a picture of a geostationary broadcast satellite?

"Resolved images of a geostationary satellite were obtained on October 30, 2009, with the adaptive optics on the largest telescope on the planet, the 10 m Keck-II on the 14000 foot summit of Mauna Kea....
Organic Marble's user avatar
12 votes
Accepted

Is it possible to control the operation of the Hubble Space Telescope from ground stations?

Yes, Hubble is actively controlled from the ground. See this NASA page on Hubble Mission Operations Examples include monitoring and adjusting the spacecraft’s subsystems (e.g., power, thermal, ...
Polygnome's user avatar
  • 6,956
11 votes
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What's the largest aperture telescope sent beyond the Earth-Moon system?

Voyager's Infrared Interferometer Spectrometer (IRIS) has an aperture of 0.5 m (19.685"). This is not an imaging instrument though (resolution=1 pixel). The large aperture was needed to provide ...
Hobbes's user avatar
  • 128k
10 votes

Are space camera sensors usually round, or square?

Silicon wafers are sliced from a giant single crystal of silicon called a boule, which is grown from a seed crystal dipped in and then slowly pulled from molten silicon. Circuits such as CCDs (and ...
uhoh's user avatar
  • 149k
9 votes
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How did Skylab's electrographic ultraviolet camera work?

Similarly to night vision devices, the light sensitive part is the photocathode, which releases electrons when hit by photons. The electrons at the photocathode are accelerated by the -25 kilovolt ...
szulat's user avatar
  • 773
8 votes

Could a 21 meter space telescope detect the nearest exoplanets?

As of 2017, 22 exoplanets have been imaged directly. The most distant of those is 1200 ly away. This shows 4 of them orbiting HR 8799, which is 128 ly away: These observations are good enough to ...
Hobbes's user avatar
  • 128k
8 votes

What is the current state of affairs concerning space telescopes?

To answer your original question regarding the state of affairs of space telescopes, from the US (NASA), besides JWST, there are two large space telescope projects. Work has started on the WFIRST (...
Vince 49's user avatar
  • 2,621
8 votes

Is there any Scientific Benefit to the Lower Albedo levels on the Darkside of the Moon?

The short answer: for optical astronomy (IR through gamma wavelengths), no, there isn't any huge advantage. But for radio astronomy there are distinct advantages to being on the lunar far side, they'...
Tom Spilker's user avatar
  • 18.3k
8 votes

How does the James Webb Space Telescope take images with individual mirror segments?

Starting with this quote, After launch and deployment, the primary mirror segments, secondary, and science instruments will be misaligned relative to each other by up to several millimeters. An ...
Carl Witthoft's user avatar
8 votes

Interesting diffraction pattern on JWST composite false-color image released today (July 11) at Biden preview - how does this arise?

The James Webb Space Telescope website has a very detailed info graphic with explanations that explain the diffraction patterns. As far as I understand, the large blueish spikes in the image in the ...
DarkDust's user avatar
  • 12.5k
7 votes

What savings allowed James Webb telescope to be lighter than Hubble?

As far as the primary mirrors are concerned, HST's mirror was made out of silica glass, and had a mass of 826 kg. The primary mirror of the Hubble telescope measures 2.4 m (8 ft) in diameter and ...
lordcheeto's user avatar
7 votes
Accepted

Does the Hubble telescope use a "simple" PID-controller for its pointing control system?

Yes. According to the NASA paper "Hubble Space Telescope Pointing Control System Design Improvement Study Results", in the first full paragraph on page 2, the author states The nominal control ...
Arthur Dent's user avatar
  • 1,135
7 votes

How come we can see nearby galaxies but are unable to see TRAPPIST-1?

How do we have telescopes that are powerful enough to see nearby galaxies, such as Andromeda (M31), but are unable to see TRAPPIST-1 or the other exoplanets in its solar system in detail when TRAPPIST-...
David Hammen's user avatar
  • 74.9k
7 votes

What is the process to produce a chemical composition spectrum of a celestial body?

The spectrum you show from Titan was taken using the IRIS spectrometer aboard Voyager 1. Of course Voyager 2 had one as well. A huge amount of work went into developing and optimizing the design in ...
uhoh's user avatar
  • 149k
7 votes

How would NASA confirm the James Webb Space Telescope is undamaged after the clamp release incident?

Partial answer: Mirror testing for any telescope mirror meant to look very far away is probably about the same. They had to get the Hubble mirror to $\lambda /10$ for example and eventually did even ...
uhoh's user avatar
  • 149k
7 votes

Can James Webb take pictures of our solar system? In what ways will they differ from/compliment those from Hubble?

This blog post from NASA on July 14th summarizes some of the details included in the other answers, and also has early images of Jupiter made during the commissioning period: The blog post mentions: ...
JeopardyTempest's user avatar
7 votes
Accepted

Will the Artemis Gateway Lunar Space Station be visible from Earth by amateur observers?

Will the Artemis Gateway Lunar Space Station be visible from Earth by amateur observers? If they can see +15 magnitude stars routinely, they'll probably be able to see Gateway. Answers to Good source ...
uhoh's user avatar
  • 149k
6 votes

What's the largest aperture telescope sent beyond the Earth-Moon system?

Just for reference, here are the largest apertures (visible or almost visible) sent to every planet that I can find. Note that some of them are kind of difficult to quantify. (Sorry for the mixed ...
PearsonArtPhoto's user avatar
  • 121k

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