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Questions tagged [angular-resolution]

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22
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2answers
5k views

What detail can Hubble see on Mars?

I'm researching a scene for a sci-fi novel in which the near-future protagonists observe earth through a station-mounted telescope in Mars orbit. My goal is to understand how much detail they ...
1
vote
1answer
32 views

How to find inverse steradian from $\text{arcmin}^{-2}$ for density of galaxy

I am using a code on EUCLID future mission. The original author of this code has set a value for the density of galaxy equal to : ng = 354543085.80106884 I ...
4
votes
0answers
44 views

What actually determines the angular uncertainty of the source of a detected gravitational wave?

This answer and comments got me thinking. Astrometry 101 tells us that while we can use $\lambda/D$ as an estimator of resolution, if we can assume a point source we can determine the centroid or ...
3
votes
1answer
74 views

What is the actual resolution of Event Horizon Telescope?

I am quite impressed with the recently published image of M87* black hole. It appears that this image achieves spatial resolution well above and beyond what was available until today. But how high ...
4
votes
2answers
58 views

What resolution would earth-moon telescope achieve?

Event horizon achieved earth-size telescope by using seperate telescopes around the world to interpolate an image of a black hole at resolution of 60 arcmicroseconds. What resolution could we get if ...
3
votes
1answer
171 views

How does making a refracting telescope very long reduce the chromatic aberration of an uncorrected lens?

Below are two cropped views of "Johannes Hevelius's 8 inch telescope with an open work wood and wire "tube" that had a focal length of 150 feet to limit chromatic aberration." from Harvard University, ...
2
votes
1answer
45 views

Under what situations can an aperture mask improve the resolution of a small/medium amateur telescope? Is this demonstrable mathematically?

@antlersoft's answer describes some of the challenges to seeing any details in the small disk of Mars in small amateur telescopes. In the case of reflecting telescopes, it mentions the use of either ...
3
votes
0answers
30 views

Estimate the number of pixels required to map the full primary beam of a Radio Telescope station

I am practising some exam questions for a radio interferometry exam, and I am struggling with this question: The physical size of a single LOFAR station, operating at 150MHz is about 50m. Estimate ...
0
votes
1answer
67 views

Why is the opening in the Anglo-Australian Telescope's dome so small?

Many older or "classic" telescope domes have a horizon-to-zenith opening in the dome, and this helps speed up the thermal equilibration between the inside and outside air, decreasing turbulence and ...
3
votes
0answers
151 views

Are they really sure this isn't an Airy disk? How was that ruled out?

How do they know that this is a spherical shell of gas, and not just something like an Airy pattern-like artifact produced by the VLT's large interferometric aperture? Image from: https://www.eso.org/...
3
votes
1answer
103 views

What is the cause of all of these sharp, concentric rings around bright stars in this HST image?

ESA's HST page heic1819 — Photo Release; Hubble reveals cosmic Bat Shadow in the Serpent’s Tail is of course beautiful and stunning, but my eyes are drawn to the diffraction artifacts of the bright ...
7
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0answers
139 views

How would astronomical seeing on Mars differ from that on Earth?

Astronomical seeing is the limiting factor for the resolution of all but the smallest Earthbound telescopes. Source Stunning advances in adaptive optics (along with it's predecessor speckle ...
6
votes
1answer
183 views

How did VLT's adaptive optics obtain this resolution for Neptune? Is it really working in visible wavelengths?

This image of Neptune taken with the VLT is really impressive. The resolution is achieved by recent improvements in the adaptive optics. Gizmodo: New Super-Crisp Images of Neptune Show How Far Our ...
1
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0answers
42 views

Tracking a heliographic coordinate on CCD

Given the latitude and longitude of a heliographic coordinate, I want to place the point on a CCD image and simulate its motion for a particular duration. Though I am able to track the motion of a ...
6
votes
2answers
390 views

Can Drizzle Integration increase resolution beyond theoretical resolution of telescope?

So I was wondering, if drizzle integration actually increases details in your image if the drizzled image results in higher resolution in terms of arcseconds / pixel than the telescope would allow (...
3
votes
1answer
147 views

Why is this HST WFPC2 image so much fuzzier than the WFC3 image of the same field?

I was looking at the comparison of 2007 and 2015 HST images of the "disappearing" star N6946-BH1 in Phys.org's article Collapsing star gives birth to a black hole. The 2007 images is from the WFPC2 ...
2
votes
1answer
115 views

What resolution is needed to see a quasar through the galactic center?

The center of the galaxy is densely packed with stars and obscured by a whole lot of dust between us and it. For those reasons, groups that study the motion of stars around the super-massive black-...
9
votes
1answer
405 views

Plot of best available resolution vs wavelength - radio through gamma rays?

What I'm looking for is a graphic that shows in a general way the best available telescope resolution vs wavelength throughout the entire wavelength spectrum. So for example, there might be two very ...
5
votes
1answer
290 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 ...
5
votes
3answers
773 views

Question about Telescopes , observations and explanations of the observations

Though I am active on Physics, I am new to Astronomy. I am an amateur astronomer, actually even worse than amateur. I have just started it. I have a 60 mm objective 700mm focal length refractor which ...
4
votes
1answer
249 views

Will the E-ELT use Adaptive Optics at visible wavelengths?

In this recent BBC article I read that the European Extremely Large Telescope or E-ELT is in final design and is planned to be on line by 2024, and that (of course) it will rely heavily on adaptive ...
10
votes
2answers
328 views

Why aren't ground-based observatories using adaptive optics for visible wavelengths?

Adaptive Optics (AO) techniques allow ground based observatories to dramatically improve resolution by actively compensating for the effects of Astronomical Seeing. The atmospheric effects are quite ...
0
votes
2answers
305 views

Solar Elevation Angles — Anomaly?

"The solar elevation angle is the altitude of the sun, the angle between the horizon and the centre of the sun's disc." - Wikipedia The meridian is when the sun is directly facing earth and is at ...
8
votes
2answers
426 views

Would Adaptive Optics be Useful in Radio Astronomy?

This Question and Answer got me thinking. If atmospheric seeing at visible wavelengths is the result of refractive index inhomogeneity, would it also be a similar problem for mm to cm wavelengths? ...
1
vote
1answer
380 views

Seconds of Arc and the Unaided Eye

I've been presented with this problem: Say that Jupiter, with its diameter of 142,000 km, was located where Mars now orbits. What would be the angular size of (the newly-relocated) Jupiter ...
3
votes
1answer
696 views

What would be the maximum theoretically possible angular resolution?

I have studied some basic astronomy, but I have difficulty conceptualizing the physics of luminosity and optics. We use electromagnetic spectra to detect existence and properties of distant planets, ...
4
votes
1answer
166 views

Beamsize in radio/microwave observations

In radio/microwave observations, I understand the beamsize is the response of the telescope to a point source - effectively, the telescope's resolution. Now, the Planck satellite (par exemple) ...
3
votes
2answers
917 views

Is the angular resolution of a telescope irrespective of used eye-piece?

Suppose a telescope has aperture $D = 20$ cm. The angular resolution of such telescope, according to the Rayleigh criterion (if I have understood it correctly), is given by $$\theta = 1.22\cdot\frac{...
3
votes
3answers
780 views

Claim that 30-m class telescopes will have resolution far superior to Hubble: true?

This article makes the claim that the Giant Magellan Telescope (GMT, number 4 in the list) will have resolution 10 times better than that of Hubble, while the Thirty Meter Telescope (TMT, number 3 in ...
6
votes
2answers
557 views

Why does radio astronomy offer higher resolution images than optical?

According to this lecture,"Radio astronomy has several advantages over optical astronomy...We can make the highest resolution images, and see things happening on the smallest scales." Why is this? If ...
1
vote
1answer
1k views

What is the typical resolving power of the largest optical telescopes?

I'd like to estimate the typical resolving power of the largest optical telescopes. I've calculated the theoretical resolving power of the VLA for 21 cm light, $$R=\frac{\lambda}{B}=\frac{2.1 \times ...
8
votes
1answer
284 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 ...
65
votes
4answers
8k views

Is the moon only 60 pixels?

In doing research on vision, I have learned that "20/20" vision corresponds to a visual acuity of being able to resolve details 1 arcminute in size, that most people have around 20/15 vision, and that ...
4
votes
1answer
240 views

Inability of Hubble to clearly resolve nearby celestial objects

The Hubble space telescope performs incredibly detailed and stunning imaging of celestial bodies that are many, many light years away, and yet when it attempts to image objects within our own Solar ...
10
votes
2answers
3k views

How does a telescope measure parallax angle?

I know how stars' distances are measured by using parallax, but I want to know how the actual telescope measures the parallax angle. Any helpful links/ explanations are needed.
13
votes
2answers
1k views

How does angular resolution of a telescope translate to its parallax precision?

We can often read in the scientific and also more casual reader literature and articles about the angular resolution of various telescopes and other optical equipment, be it ground based or onboard ...