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Questions tagged [interferometry]

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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 ...
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How does the Large Binocular Telescope resolve so well in both orthogonal directions simultaneously?

The Forbes article Ask Ethan: How Does Very-Long-Baseline Interferometry Allow Us To Image A Black Hole? includes an example of optical interferometry from the Large Binocular Telescope, shown below. ...
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Why not us interferometry to take a picture of Pluto?

Interferometry is among the best ways (if not, the best way!) to have an image of a very distant object. Recently a picture of the black hole at the center of M87 was released. It is the result of ...
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What are the challenges for the building and data analysis of the CHIME telescope?

CHIME has discovered the second repeated fast fast burst recently. However, its structure is simple apparently. I wonder why we did not build a telescope before. What is the challenge? I just know its ...
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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 ...
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Can weak gravitational lensing or microlensing-induced wavefront distortion limit resolution of absurdly large aperture telescopes?

This is a theoretical question. This answer to the question If we had the right technology could we see a distant star in detail? (presumably space-based) primarily addresses the scaling of ...
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Is Optical VLBI theoretically feasible? If not why not?

There are plenty of optical interferometers in use with baselines of up to maybe 1km. As far as I can find out, they all work by directly collecting the light at all the telescopes, using mirrors to ...
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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/...
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Could the E.H.T. produce an image of the human artifacts on the moon?

Two days ago the New York Times featured the Event Horizon Telescope (E.H.T.), a huge virtual radio telescope emerging from combining data from several dishes scattered around the world. While the E.H....
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Converting Jy/beam to Jy?

Maybe its a dumb question, but to convert Jy/beam to Jy, I just have to multiply it by the beam size in sr right? Being $\Omega$ the beam size: $\Omega = \frac{\pi \theta_{maj} ~~ \theta_{min}}{4 \...
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What are the raisons d'être for the Large Binocular Telescope “binocularity”?

edit: The short form of the question is Why are there TWO telescopes?? A longer version follows. The Large Binocular Telescope (and LBT blog as source of images below) has two 8.4 meter diameter ...
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What is a “limited array”?

I'm reading about the history and making of ESO's Very Large Telescope and I've found this article that says the scientific community had a choice between three suggestions: a one-piece 16m-telescope, ...
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Can two detectors for gravitational waves be combined into a very long baseline interferometer?

While detectors for gravitational waves are interferometers themselves, the question here is about an increase in resolution resulting from two or more detectors far away from each other.
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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://...
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Why don't we use amateur astronomers' telescopes to create a huge interferometer?

Some telescopes in space have been proposed to function as an interferometer. Being placed several hundreds or thousands of kilometers apart they could actual image exoplanets directly. To my ...
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Calculating angular diameter amplitude from angular diameter variations of Cepheid variable

I'm a high school student but have as much interests in Cepheid variable as the professionalists. I'm trying to derive independent distances to Cepheid with the Baade-Wesselink method. I got the ...
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Multi-messenger astronomy: what is the potential of simultaneous detection of gravitational waves and neutrinos from a supernova?

Thanks to the efforts of the aLIGO team, gravitational wave astronomy is a reality. At the same time, neutrino detectors like Hyperkamiokande are becoming much more sensitive. My question is: what ...
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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 ...
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Can any radio telescope be hooked up with the Very Long Baseline Array, or other interferometers?

The Very Long Baseline Array uses both Arecibo and Spectr-R, the world's largest space telescope with 10 m diameter at Lunar distance, as well as many other antennas. Are there any particular ...
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Giant variation of the proposed eLISA mission using reflectors on Earth and the Moon possible?

I was thinking about the proposed ESA mission eLISA, which is essentially a space version of the LIGO experiment, and it occurred to me that trailing three satellites behind the Earth's orbit seemed ...
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Can the expansion of spacetime be directly measured with laser interferometry (like GW can)

LIGO has a mind boggling sensitivity. What would it take to directly measure the expansion of spacetime, along the laser beam? I suppose it could be done at interplanetary scale.
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What makes small interferometers useful? Like NIRISS on JWST

NIRISS is an instrument on the James Webb Space Telescope. It has a "non-redundant aperture mask" which obviously covers most of the area of the sensor. It seems to be advantageous for high contrast ...