Questions tagged [interferometry]
Questions about astronomical observations which involve superimposing waves received by multiple, physically separated, receivers to obtain higher angular resolution.
67
questions
2
votes
1
answer
83
views
Do we have the technology to create a satellite telescope constellation that uses interferometry?
Apologies for putting the bulk of the question in the description. I'm honestly not sure how to ask this properly. The idea for this question came from a Vsauce video from several year ago I can't ...
- 23
3
votes
3
answers
367
views
About angular diameter, parallax and image of the nearest neutron star RX J185635-3754
I have a big doubt about our allegedly nearest (X Ray isolated) neutron star, also known as the Walter star, one of the members of the "Magnificent Seven stars": RX J185635-3754.
So I came ...
- 201
2
votes
0
answers
64
views
Angular diameter and length of baseline
How did they determine the angular diameter, please? How to predict the baseline length with the first lobe?
Thank you.
https://www.chara.gsu.edu/public/basics-of-interferometry
If they are ...
- 781
2
votes
2
answers
103
views
Could we hear alien radio transmissions using radio interferometry?
Suppose money and engineering wasn't a concern. Could we actually build a bunch of radio telescopes in space, and use radio interferometry, so that we could actually hear the sort of radio ...
- 51
3
votes
1
answer
146
views
Telling bounces in LIGO interferometer
How do they know the number of times the laser bounces back and forth, in the 4 km arms of the interferometer, before the laser light is picked out to the reading sensor?
See under “The Longer The ...
- 381
0
votes
0
answers
47
views
W in the brightness distribution
What is W in the brightness (intensity) distribution, please?
Alpha is the position of the star; lambda, the wavelength; t, the time; P, the polarization.
Thank you
- 555
2
votes
1
answer
72
views
Squared visibility in astronomy
Why is preffered to use squared visibility instead of visibility in long-baseline interferometry, please?
- 781
13
votes
2
answers
256
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 ...
- 155k
1
vote
3
answers
136
views
How does Very Long Baseline Interferometry work?
According to internet sources, this technique increases the effective diameter of the telescope, thus improving the angular resolution of the telescope. However I don't understand how this actually ...
- 779
11
votes
1
answer
2k
views
Can the Hubble constant be measured directly?
By my calculations, the expansion of the universe should cause LIGO’s interferometers to alternate between constructive interference and destructive interference every couple days. Is this a practical ...
- 291
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
2
votes
2
answers
186
views
What is stopping Event Horizon Telescope the size of the Earth’s orbit?
There is a proposal to include a radio sensor in a telescope going to the Sun-Earth L2, getting 120x improvement in angular resolution to EHT. Knowing nothing about interferometry, it seems pretty ...
- 123
6
votes
2
answers
106
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
1
answer
317
views
If we put a radio telescope on Mars and use it in array with earth radio telescopes, how much will we able to see?
If we put a radio telescope on Mars and use it in array with earth radio telescopes, how much will we able to see? Will it allow us to see planets, like we do with black hole?
- 256
1
vote
1
answer
209
views
Response function of LIGO
"Laser Interferometer Gravitational-wave Observatory" (LIGO) is a marvel of precise engineering and the world's largest gravitational wave observatory. LIGO, which consists of two massive ...
- 311
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
2
votes
1
answer
126
views
Are there any space-based observatories that use interferometry?
Ground-based interferometers such as ALMA have enabled many discoveries. It seems like sending a fleet of small telescopes would be feasible (smaller telescopes are easier to send into space than ...
- 17.6k
4
votes
1
answer
136
views
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
3
votes
1
answer
378
views
Estimate upper limits on flux values in the case of a non-detection?
I have ALMA data which are non-detections of some spectral lines in a protoplanetary disk. The data is in the form of spectral cubes. I am hoping to estimate an upper limit on the flux of each of the ...
- 1,386
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
7
votes
0
answers
496
views
Convert from Jy/beam km/s to W/m$^2$
I need to compare some ALMA observations of a protoplanetary disk to disk-integrated fluxes obtained from a model.
The ALMA observations are upper limits of non-detected spectral lines, where the RMS ...
- 1,386
1
vote
0
answers
41
views
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
views
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
115
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
views
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
1
answer
956
views
In astronomical interferometry, what values do the points in the uv-plane have?
As I understand it, the image of an interferometer is the inverse fourier transform of the information in the uv plane. For each baseline (vector between any two telescopes in the array), representing ...
- 1,800
2
votes
1
answer
50
views
The role of 'the interference of waves' in VLBIs'
I've been trying to find out how VLBIs work. It says in this book I've read that many radio telescopes around the world work in tandem to use the interference of waves to get a clearer picture of ...
- 23
2
votes
2
answers
103
views
Why does the Simbad page "A.A. Michelson's Jovian Galilean-satellite interferometer" show data for Betelgeuse?
When searching for things related to How did Michelson measure the diameters of jupiter's moons using optical interferometry? I came across the ui.adsabs.harvard.edu entry A. A. Michelson's Jovian ...
- 30.7k