Linked Questions

11 votes
2 answers
899 views

Would Adaptive Optics be Useful in Radio Astronomy?

The question Why is this video showing radio waves transmitted from a radio telescope? and this answer to it got me thinking. If atmospheric seeing at visible wavelengths is the result of refractive ...
uhoh's user avatar
  • 30.7k
7 votes
3 answers
387 views

How can the Event Horizon Telescope image Sgr A* when it's not visible from all sites at one time?

I went to https://eventhorizontelescope.org/array and read about the ten sites listed as part of the EHT, I have a mashed-up screen shot of them below. I made a little script also shown below with ...
uhoh's user avatar
  • 30.7k
3 votes
1 answer
1k views

Which techniques are used to convert radio signals received by antenna to images?

I realized that after answering the question How do astronomers convert radio signals received by their antenna to images? I had missed the point that the OP was only asking about software. I've ...
uhoh's user avatar
  • 30.7k
3 votes
2 answers
270 views

Just how fast is a Fast Radio Burst thought to be?

According to Wikipedia's Fast Radio Bursts; Features are recorded they The component frequencies of each burst are delayed by different amounts of time depending on the wavelength. This delay is ...
uhoh's user avatar
  • 30.7k
3 votes
1 answer
436 views

How do astronomers convert radio signals received by their antenna to images?

I'm very new to radio astronomy and I am curious how an the signals received by a radio antenna are converted to data on a computer and then images? Is there a popular software to use for this, or do ...
Thomas's user avatar
  • 161
6 votes
1 answer
290 views

How does ALMA produce stable, mutually coherent ~THz local oscillators for all of their dishes?

The ALMA (Atacama Large Millimetre/submillimetre Array) radio telescope's band-10 capabaility is now operational, per this answer. That's confirmed by NRAO's First Science with ALMA’s Highest-...
uhoh's user avatar
  • 30.7k
2 votes
2 answers
184 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 ...
Ahmbak's user avatar
  • 123
3 votes
1 answer
199 views

How, precisely, do radio astronomers detect (and record) the phases of waves for interferometry?

Interferometry is always in the news, and at radio frequencies it has been for a long time... The popular press always talks about directly 'interfering' two waves as they come in, but can they tell ...
Kurt Hikes's user avatar
  • 5,177
2 votes
1 answer
200 views

Why do radio telescopes, but not shorter wavelengths, have this Big Data problem?

Only with new radio telescope arrays like ALMA and SKA, have I heard of this "problem" with too much data come up. Too big to store. That one cannot archive it all for future studies, but that one has ...
LocalFluff's user avatar
  • 11.4k
6 votes
1 answer
155 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 ...
uhoh's user avatar
  • 30.7k
5 votes
1 answer
119 views

Could images of (very) nearby targets be recovered from Event Horizon Telescope data?

Reading this question I was struck by the fact that the "pointing" of an interferometer is effectively done in the correlator, at least within the common field of view of all the telescopes, which is ...
Steve Linton's user avatar
  • 10.3k
3 votes
1 answer
127 views

Why were only 4 days of data used in the M87 EHT observation?

I wonder why only 4 days of data were used in the M87 Event Horizon Telescope (EHT) observation. What is preventing you from obtaining a more detailed and clearer image over a longer period of time?
Aegean's user avatar
  • 109
4 votes
1 answer
390 views

Will the SKA's total bandwidth still exceed the Earth's internet's bandwidth?

In the early 2010's there were many popular articles that said that the total bandwidth of the the Square Kilometer Array's optical fiber network for raw data from each dish would be larger than the ...
uhoh's user avatar
  • 30.7k
5 votes
1 answer
166 views

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 ...
uhoh's user avatar
  • 30.7k
1 vote
0 answers
82 views

Examples of radio correlations over times much longer than interferometric baselines?

Very Long Baseline Interferometry or VLBI such as the Event Horizon Telescope or JPL's delta-DOR (see below) uses baselines of the order of the Earth's diameter. Spacecraft position determination How ...
uhoh's user avatar
  • 30.7k