Questions tagged [radio-telescope]

Questions related to the instruments used to perform observations in the radio frequency range.

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Do circa 1 THz radio telescope front end amplifiers actually down convert before amplifying? At what frequency does amplification become untenable?

A discussion of how astronomers view where "radio" ends and "infrared" begins under What does the celestial sphere look like in thermal IR? led me to wonder just how high of a ...
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Why aren't concentrated solar power plants use for astronomical observations of some type?

Concentrated solar power plants use reflecting surfaces to gather the sun rays for energy production. Currently they sit idle at night and are not used for anything. These have huge collection areas, ...
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12 votes
3 answers
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How are radio telescopes pointed?

In the past, I worked as a programmer in a radio astronomy station, and since then I have a question on my mind. To observe a star with a telescope, we locate its location with our eyes and then we ...
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Is it possible to make (or buy kit) DIY portable radio telescope that I can place on the balcony like optical telescope?

I want to have a small radio telescope to use on balcony instead of optical when sky is cloudy (it is very often). Is it possible? What objects can be observed by that telescope? Is it possible to use ...
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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?
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TPoint software, INDAT command - Format 4 (ALTAZ)

I am working (in fact, trying to work) with TPoint for improving a solar telescope pointing calibration (SST, in Casleo, AR) and stumbled on the input data for INDAT command. SST is a multibeam solar ...
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1 vote
1 answer
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How would the surface of Mars compare with the Atacama desert for millimeter wave (and shorter) radio astronomy?

In this answer to What kind of experiments would a scientist do on Mars? I suggest that the resemblance of the ALMA array's site in the Atacama Desert to the surface of Mars suggests millimeter ...
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6 votes
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Why Nyquist Sampling Rate depends on Bandwidth and not max frequency?

Is the Nyquist sampling rate same for different bands if those bands have same bandwith? E.g. Would the Nyquist Sampling rate be same for 1000-1400 MHz band as for 100-500 MHz band because both the ...
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5 votes
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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 ...
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1 vote
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How to properly compare radio to optical/NIR images?

I mainly work with radio continuum data and recently I started working on some HST hydrogen recombination line datasets to compare with the radio data that I have, but I'm very confused about what is ...
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8 votes
2 answers
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Is Carl Sagan's famous "snowflake" quote correct?

“The total amount of energy from outside the solar system ever received by all the radio telescopes on the planet Earth is less than the energy of a single snowflake striking the ground.” ― Carl Sagan,...
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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 ...
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How does the Latvian branch of LOFAR radio telescope array communicate its data without a network connection?

LOFAR technical information links to LOFAR Map from which a screenshot below shows HBA, LBA and Network options. Both the high and low band arrays are distributed in a number of clusters around Europe....
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What is notable about LOFAR's sub-arcsecond radio resolution of distant galaxies? Does lower freq. range enable new capabilities that mm wave can't?

The BBC's Astronomers see galaxies in ultra-high definition covers some news related to papers in Astronomy & Astrophysics' dedicated, open access issue Sub-arcsecond imaging with the ...
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If the visibility function is the Fourier transform of the sky brightness distribution, why do you need the dirty beam and dirty image to find it?

In radio astronomy, the dirty image is equal to the inverse Fourier transform of the uv-plane coverage times the sampled visibilities. The dirty image is also equal to the convolution of the "...
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Do radio telescopes see other stars better at night?

As you know, we don’t see stars with the naked eye during the day because of the visible glare of our Sun. As I understand our Sun emits radio frequency waves, too. Is there a radio ‘glare’ from the ...
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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 ...
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Did the Spectr-R space-based radio telescope use on-board accelerometer to measure non-gravitational acceleration for baseline correction?

This answer to Why is space-based VLBI scattering sub-structure "Hopefully, a new promising tool to reconstruct the true image of observed background target(s)"? summarizes the contribution ...
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What radio frequency ranges are most beneficial for astronomy?

I cannot get the idea of citizen radio astronomy out of my head, and choosing an antenna (design) heavily depends on the desired frequency range. The Arecibo telescope as my gold standard operated 300 ...
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2 votes
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Is Sofia a radio telescope proper?

I usually think of SOFIA, the Stratospheric Observatory for Infrared Astronomy as an infrared optical telescope: SOFIA uses a 2.5 m (8.2 ft) reflector telescope, which has an oversized, 2.7 m (8.9 ft)...
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How can we install a radar on radio telescopes like FAST or GMRT?

Recently I came across an article mentioning that ever since the failure of Arecibo telescope, we only have one asteroid radar imaging telescope which is Goldstone observatory. The article also ...
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What is the significance of the velocity resolution in spectral line observations using radio interferometry?

I've always struggled to conceptualize the term "velocity resolution" in spectral observations. In principle, it is simple to calculate. For example, one can take the spectral width and ...
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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 ...
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Open source library to calculate image from signals of a distributed set of radio dishes?

The National Radio Astronomy Observatory's Q&A "How To Make Images With a Radio Telescope" says The most straightforward way to make a radio image with your satellite antenna system, ...
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Can one build a distributed radio telescope?

I understand some radio telescopes are built as arrays of receivers. Could one build an array from a heterogeneous set of receivers in scattered locations? Suppose a large number of persons each ...
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28 votes
4 answers
5k views

Could we carve a large radio dish in the Antarctic ice?

Could we carve a large radio dish in the Antarctic ice that could replace the Arecibo Observatory? Could this work, and what would be some potential limitations?
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Recommend a radio calibration target for amateur radio telescope

I have a small antenna and radio system that can receive frequencies between 1MHz and 1GHz. The system has a discone antenna. I plan to do some aperture synthesis based on the daily rotation of the ...
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1 vote
2 answers
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Opening VLA Export Format data on Windows

I recently downloaded some data from the NRAO archive. It came as a file in the "VLA export format" with the extension .xp1. From what I gather I can open this using some software called ...
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3 votes
1 answer
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Maritime telescopes: Stabilisation requirements for optical vs. radio telescopes?

SOFIA stands for Stratospheric Observatory for Infrared Astronomy. She says: My telescope stays stable with a spherical bearing, shock absorbers, and gyroscopes. I suppose a similar system would ...
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Current topics on Radio Astronomy and looking for advice

Background and Question: I'm an undergraduate student interested on Radio Astronomy. I consider myself enthusiastic about it and I project myself following this "path" so I'd like, ...
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Do ASKAP and ALMA have "fast dump" interferometric modes? Can they see and perhaps report Fast Radio Bursts in real time?

Chatterjee et al 2017 The direct localization of a fast radio burst and its host nicely shows a VLA detection of a repeating FRB in 5 millisecond steps nicely demonstrating the dispersion slope ...
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2 votes
1 answer
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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 ...
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52 votes
4 answers
6k views

Is there any role today that would justify building a large single dish radio telescope to replace Arecibo?

It seems that most of the modern radio astronomy instruments and observation that make the news are interferometers or phased array systems of one kind of another. Is there any application left for ...
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5 votes
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Building a floating, ocean-going giant radio telescope?

Given the loss of the Arecibo telescope: Is anybody aware of any efforts or studies towards a floating, ocean-going radio telescope of with 500m diameter or more? The idea is floating (pun intended) ...
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1 answer
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Hypothetical CMB space telescope design problem, received power from extended thermal source versus receiver front end NEP?

Consider the example of a large radio dish antenna in space equipped with a heat shield protecting it from the Sun. Let's say the amplifiers front-end effective temperature (for purposes of noise ...
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3 votes
2 answers
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Is it possible to filter radio-waves using another radio telescope?

When making an observation using a radio telescope, is it possible to filter out noise coming out from a known source by using another telescope that will focus on that noise source? By filtering, I ...
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4 votes
0 answers
222 views

How could the loss of the Arecibo Observatory have been prevented?

Would more preventative maintenance, more regular inspection of the cables have helped? Robotic/drone inspection systems? Could the right robotic system have done work to save it in the last few ...
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33 votes
4 answers
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What will succeed the Arecibo Observatory?

Just a few minutes ago, I got a notification from Space.com stating that the Arecibo Observatory will be, sadly, decommissioned due to extensive damage to its structure. So, with the loss of one of ...
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6 votes
2 answers
214 views

How accurately could late 50s - early 60s humans have mapped the solar system?

What if early SETI investigations had focused on our own solar system, rather than distant stars? Given the technology that existed around the 1950s, how much surveillance would humanity be able to do?...
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3 votes
1 answer
190 views

Is there an IRAM satellite that measures thermal radiation at 250 GHz, or was this a ground-based instrument?

The Nature Research Letter A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation (also here and here) says about half-way through: We now reassess Eris’ surface ...
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2 votes
0 answers
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Software for simulating/calculating a known EMW pulse propagating in ISM, including dispersion, scattering, etc

Could you please let me know, if there is any software/code/tool for simulating/calculating the result of a short EMW pulse (waveform is exactly known) propagating in the ISM for long distance, ...
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3 votes
1 answer
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How far can we detect lightning in radioastronomy?

The wikipedia article on whistlers has this information: Voyager 1 and 2 spacecraft detected whistler-like activity in the vicinity of Jupiter known as "Jovian Whistlers", implying the ...
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5 votes
2 answers
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Is there an advantage to the equatorial region of the far side of the moon for a radio telescope or would any crater on the far side work?

If nearly any crater on the far side of the moon will work, and not just equatorial craters, then we could pick craters near the possible future Artemis base at the South pole which would allow easier ...
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1 vote
0 answers
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How can I determine the location of an object for one observer given the location for another?

I know an object exists at the location of the beam-pointing-center of a radio telescope. I know the elevation/azimuth of the beam pointing center, as well as it’s “location” in galactic coordinates. ...
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1 vote
1 answer
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Why did it take five years to "figure out" how to use astrometric calibration sources to deblur LOFAR images?

Quanta Magazine's The Hidden Magnetic Universe Begins to Come Into View is a fascinating review of a rapidly evolving field in astronomy. It contains some statements: In their paper last year, van ...
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1 vote
1 answer
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How is the field of view of a radio telescope determined?

It’s my understanding that radio telescopes can only receive signals that hit the dish within a certain range of angles. How is that angular range determined i.e. measured and/or calculated?
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1 vote
1 answer
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How can I correct for transit time?

I know the exact time a radio telescope detected a transient event. I also know the exact location of the telescope, and the galactic coordinates (galactic longitude, latitude) and right ascension and ...
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6 votes
1 answer
72 views

What is the role of the mesh on which dipole elements of the MWA antennas are placed?

I was reading about the radio telescope - Murchison Widefield Array (MWA) situated in Western Australia. Antennas of this telescope are quite unique and different from the usual dish radio telescope. ...
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2 votes
1 answer
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How is Cosmic Microwave Background's temperature measured?

How do Cosmic Microwave Background missions/telescopes measure CMB temperatures? I understand that CMB has Planck's spectrum. So I was thinking one strategy could be to measure the spectral radiance ...
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7 votes
1 answer
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Is there any work underway to push the long baseline capabilities of the Event Horizon Telescope to sub-millimeter wavelengths?

The Max Planck Institute for Radio Astronomy's press release Something is Lurking in the Heart of Quasar 3C 279; First Event Horizon Telescope Images of a Black-Hole Powered Jet shows a stunning ...
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