36 votes
Accepted

What will succeed the Arecibo Observatory?

There's no simple answer. In the immediate future, different radio telescopes around the world will pick up the slack in various ways; how that happens will depend on the needs of individual observers ...
  • 34.4k
36 votes

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

Arecibo wasn't just a radio telescope, it was a radar telescope, bouncing megawatt-level radio signals off various bodies in the Solar System. A single-dish transmitter is far superior to a phased-...
  • 3,031
31 votes
Accepted

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

Great question! There are many open and active antarctic permanent bases and several antarctic astronomical observatories. There are even major large projects that involve substantial drilling and ...
  • 30.6k
29 votes
Accepted

Can I sense a bright star pointing an eight foot antenna towards it?

Stars are too dim for amateur radio equipment. There are two possible radio sources that you can detect: the sun and Jupiter. Jupiter is particularly interesting as interactions between Io and its ...
  • 96.2k
25 votes

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

Having a large dish gives you a large collecting area and hence better sensitivity. Building a multitude of receivers with the same collecting area, each having its own feed and electronics, is more ...
  • 124k
24 votes

How are radio telescopes pointed?

Well, even most optical telescopes aren't steered by hand and guided by human eyes - aside from a small fraction of objects, most sources are too dim to be seen by the naked eye or even with ...
  • 34.4k
18 votes
Accepted

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

Single-dish telescopes have advantages over interferometers in a few areas; existing answers have touched on some of them. Collecting area is extremely important, as Rob Jeffries mentioned, and you ...
  • 34.4k
15 votes

Building a floating, ocean-going giant radio telescope?

I would be extremely concerned about the ability of such a telescope to make adequately precise measurements, given the motion of the water. The leading radio telescopes have their mirrors and ...
  • 34.4k
13 votes

What will succeed the Arecibo Observatory?

As you said, the loss of Arecibo will definitely put a dent in the field of radio astronomy. As for what will help take its place - there are a couple options. Green Bank Observatory has been and ...
13 votes

Do radio telescopes see other stars better at night?

The Sun doesn't substantially impact radio observations during the day, because radio telescopes operate at long wavelengths. In general, light at longer wavelengths scatters less than light at ...
  • 34.4k
12 votes

What will succeed the Arecibo Observatory?

The big loss is to radar astronomy. Arecibo was one of only two radar telescopes in the world in regular use, and was by far the more powerful: a 300 meter antenna and megawatt transmitter, versus ...
  • 3,031
12 votes

How are radio telescopes pointed?

There are several ways to point a radio telescope. Some radio telescopes are mounted with an optical telescope pointed in the same direction. The user moves the optical and radio telescopes together ...
  • 15.4k
10 votes

Why does the Event Horizon Telescope (EHT) not include telescopes from Africa, Asia or Australia?

Would it increase the diameter if they would include some from there? No. Not by much, at least. The telescopes are already ~20,000 km apart, so you can't create a longer baseline that still has a ...
  • 2,974
10 votes
Accepted

What radio frequency ranges are most beneficial for astronomy?

Radio astronomy involves a wide range of frequencies, covering the range from $\sim$10 MHZ to $\sim$100 GHz.$^{\dagger}$ With four orders of magnitude to work with, the most valuable band depends ...
  • 34.4k
10 votes
Accepted

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?

I'm one of the researchers involved with the International LOFAR Telescope (ILT) scientifically and technically, and have also contributed one of the papers and images you may have seen appear on ...
  • 316
9 votes

Can I sense a bright star pointing an eight foot antenna towards it?

As others have noted, you will not be able to detect a star using an oscilloscope and an antenna. The received signal level is too low, and the oscilloscope not nearly sensitive enough. A radio ...
  • 265
9 votes

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

The biggest limitation is that it would be in Antarctica, one of the most inhospitable places on Earth. Getting there is hard. Living there is harder. Everything needs to be flown in and if something ...
  • 96.2k
9 votes
Accepted

Can one build a distributed radio telescope?

Yes, we can do radio astronomy with heterogeneous, geographically distributed antennas. The VLBI is an excellent example. Of course, the antennas have to be similar in some ways for it to work: If ...
  • 15.4k
8 votes

Can I sense a bright star pointing an eight foot antenna towards it?

Connecting an antenna directly to oscilloscope will not give reception, even with a strong radio source. First problem is the power level. Typical received power from antenna would be around -100 dBm,...
  • 1,471
8 votes

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

Other answers deal with the properties of the ice sheet as a stable base for a precise-dimensioned equipment (it is not), the snow that will try to bury the telescope, etc, etc... A different from the ...
  • 2,538
6 votes
Accepted

How did single dish (or single receiver) radio telescopes originally generate images?

They scan the object, if you point the dish a a point in the sky as the Earth rotates the dish scans across astronomical objects, then move the dish to point at a slightly different position and let ...
6 votes

Amateur radioastronomy: dish suggestions

The size of your dish determines two things: Along with the temperature of your electronics, determines the signal-to-noise ratio of your telescope. The size of your dish determines the angular ...
  • 586
6 votes
Accepted

Did Arecibo's secondary optics compensate aberrations when viewing farther away from vertical?

While the statement in the block quote about the sphere is correct as far as it goes, was the shape of the correcting optics (secondary, etc) above also independent of where you look? Or ideally would ...
6 votes

Why does the Event Horizon Telescope (EHT) not include telescopes from Africa, Asia or Australia?

tl;dr: @Hobbes' answer is demonstrably wrong; the EHT takes a large fraction of its data when the target is not visible from one of the extreme sites. If there were sites distributed all the way ...
  • 30.6k
6 votes
Accepted

Why does the Event Horizon Telescope (EHT) not include telescopes from Africa, Asia or Australia?

Why does the Event Horizon Telescope (EHT) not include telescopes from Africa, Asia or Australia? Why were not they included? Africa doesn't have a radio telescope in the frequency range necessary (...
  • 2,533
6 votes
Accepted

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

The Nature paper by Bertoldi et al. (2006) says: Our millimetre observations were performed with the Max-Planck Millimeter Bolometer (MAMBO-2) array detector at the IRAM 30 m telescope on Pico Veleta,...
  • 7,488
6 votes
Accepted

Is it possible to filter radio-waves using another radio telescope?

Coherent interfering signals are usually referred to as RFI (or Radio Frequency Interference). One could certainly digitally filter out a coherent interfering signal from a telescope by observing ...
  • 15.4k
6 votes

How are radio telescopes pointed?

If an amateur astronomer can see and identify a specific star in the sky with their naked eye, they can point their telescope at that star. Many telescopes come with smaller spotting scopes attached ...
5 votes

Amateur radioastronomy: dish suggestions

I have a used 2.4 metre mesh C band dish that I picked up for free that I will be converting for observing the 21cm hydrogen line @ 1420MHz. I was lucky with this dish as it's in as new condition, but ...
5 votes
Accepted

Can radio telescopes such as arecibo image the subsurface of asteroids or planets?

It is important to understand how this process works. The method described in your article is known as Bistatic Radar. In effect, a transmitter sends out a signal (generally a radio telescope in the ...
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Only top scored, non community-wiki answers of a minimum length are eligible