All Questions
Tagged with interferometry observational-astronomy
21
questions
13
votes
2
answers
258
views
Why hasn't VLBI been used to try and image giant exoplanets?
A Jupiter-sized object at 10 pc subtends an angle of 0.0001 arcseconds (100 micro-arcsec) at the Earth. The Event Horizon Telescope interferometry network is capable of a (demonstrated) angular ...
- 156k
3
votes
0
answers
79
views
Mega Telescope using gravitational lensing and interferometry
I have been thinking about this crazy telescope idea, but I am not smart enough to understand if it's technically possible. I understand from an engineering and practical point of view it's a long way ...
- 51
6
votes
2
answers
107
views
In terms of results, how similar is a bunch of telescopes across the globe to an Earth-sized telescope?
The Event Horizon Telescope emulates an Earth-sized telescope by syncing a bunch of radio telescopes across the planet to do take pictures with a small enough angular resolution to take pictures of a ...
- 1,758
1
vote
0
answers
99
views
Maximum number of pixels across a synthesized beam in an ALMA image?
I have some ALMA data, from which I have created images using the TCLEAN task in CASA.
I understand that with this type of data, it is necessary to have at least 2 pixels across the FWHM of the ...
- 1,386
4
votes
1
answer
136
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Have interference effects (in space) ever been observed by a single instrument, as opposed to interferometry?
Not asking about:
Interferometry can be done with multiple instruments who's light paths or signals are combined interferometrically, or even between different parts of a single aperture, e.g.
What ...
- 30.7k
6
votes
1
answer
1k
views
rms noise, confusion and dynamic range in radio images
I have been trying to understand imaging in radio astronomy. Below are some of my questions related to it and my understanding of their answers. I am not very confident about my understanding of them ...
- 131
1
vote
0
answers
41
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How does speckle imaging fit in to 21st century high resolution imaging from ground based observatories?
Phys.org's Astronomers uncover evidence that there could be many more Earth-sized planets than previously thought references Speckle Observations of TESS Exoplanet Host Stars. II. Stellar Companions ...
- 30.7k
6
votes
1
answer
156
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Reference request (explaining) how optical correlators combine light from multiple telescopes to produce ultra-high resolution interferometric images?
This is a reference or resource-request because it may be too challenging to explain in an answer post, but if you'd like to attempt a short summary as well, that will be great!
I have a basic ...
- 30.7k
7
votes
1
answer
106
views
What could a cloud of mini radio dishes see?
Suppose an astronomer gave a 1 m radio dish to 500 people scattered over the face of the Earth and connected them to the internet. The people are directed to set their radio antennae up in their ...
- 652
4
votes
1
answer
118
views
What is the significance of using baseline pairs in radio interferometry?
Radio interferometry utilizes arrays of smaller telescopes that are linked together to synthesize a larger aperture telescope. Astronomical radio observatories, such as the Very Large Array in New ...
- 1,111
11
votes
1
answer
610
views
Was GRAVITY built to look at one star?
GRAVITY (shown below) is a interferometric combiner of near infrared light from four very large telescopes called The Very Large Telescope in order to make careful astrometric measurements near the ...
- 30.7k
2
votes
1
answer
119
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What does a narrow-band "point spread function" look like for long exposures from the VLT's large interferometric aperture?
In interferometric radio astronomy UV plots are the first step in understanding what a point spread function (PSF) will look like for a given location in the sky observed over a period of time. The ...
- 30.7k
4
votes
0
answers
137
views
How did Michelson measure the diameters of jupiter's moons using optical interferometry?
In Betelgeuse: How its Diameter was measured (Chant, C. A., Journal of the Royal Astronomical Society of Canada, Vol. 15, p.133, Bibliographic Code: 1921JRASC..15..133C) the author says:
The paper in ...
- 30.7k
3
votes
1
answer
257
views
Has optical interferometry been done at radio frequency using heterodyning with a laser in a nonlinear material?
If one collects narrow band optical emission from a large telescope with frequency $f_1$ and mixes it in a nonlinear crystal with laser light of a nearby frequency $f_2$, it would produce two new ...
- 30.7k
1
vote
1
answer
302
views
Can the interferometer called "Gravity" measure "a few centimeters on the Moon"?
Phys.org's Very Large Telescope sees star dance around supermassive black hole, proves Einstein right links to several ESO videos, including Interview with Reinhard Genzel (in English). After ...
- 30.7k
2
votes
1
answer
128
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How do they know the non-uniformities seen on the disk of π¹ Gru are real and not artifacts?
@RobJeffries' answer to What is this web on the surface of the Sun? explains why convection cells on some other stars can be far larger than they are on our Sun and includes a near-infrared VLT ...
- 30.7k
2
votes
1
answer
261
views
Will the Magdalena Ridge Optical Interferometer be able to image extended objects like the surface of the Moon?
Inspired by several questions:
When will a moon landing site be visible via telescope?
Could the E.H.T. produce an image of the human artifacts on the moon?
Picture of equipment left on the Moon?
...
- 30.7k
0
votes
1
answer
67
views
Does interstellar cloud obstruct or reduce the visibility?
We just pictured a medium distant black hole by combining data from various observatories around the world. That's when I wondered if interstellar cloud blocks the visibility at multiple position in ...
3
votes
1
answer
96
views
What are the challenges for the building and data analysis of the CHIME telescope?
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) has discovered the second repeated fast radio burst recently. However, its structure is simple apparently. I wonder why we did not build a ...
- 3,137
1
vote
1
answer
4k
views
How are people converting intensities in Janskys to Kelvin?
I'm reading some ALMA proposals and I am often seeing a conversion from Jy to Kelvin when, for example, people quote noise levels or source flux.
For example on their sensitivity calculator
(https://...
- 190
2
votes
1
answer
104
views
Is radar interferometry used, or feasible, for ground based astronomy?
I've heard of "interferometric synthetic aperture radar" being used for Earth observation from satellites and airplanes. Is active radar used interferometrically for astronomical purposes too? Such as ...
- 11.4k