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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 magnetic field produce beams of radio waves that sweep past earth every 10 hours. These are detectable in the amateur range, at about 20 MHz. Nasa make a kit ...


10

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 telescope consists of an antenna, an amplifier, and a receiver (that incorporates other amplifiers and other stuff besides - like filters and mixers to select the ...


10

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 simultaneous view of the target. Don't forget: Earth is a sphere. Only one half of that sphere can observe M87 at the same time. Telescopes in the Eastern ...


7

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, i.e. $10^{-10}\,\textrm{mW}$. A typical oscilloscope has an input impedance of 1 Mohm, which means if all the received power went there, it would give a ...


7

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, Spain. This is a ground-based telescope in the Spanish Sierra Nevada mountains at 2850m to try and get above as much of the precipitable water vapor, which ...


6

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 resolution you can expect. This has an approximate relationship of $$ R = \lambda / D$$ where $R$ is your angular resolution, $\lambda$ is your wavelength of light ...


5

That's the Very Large Array. The very large array is a Y shaped array of massive Radio astronomy observatory. It has the computing power to function as an interferometer. Each radio is mounted on double parallel railroad tracks, so the radius and density of the array can be transformed to adjust the balance between its angular resolution and its surface ...


5

I'm not sure what you mean by "wave modulations". Loosely speaking, there's 2 things to look for regarding alien intelligence/technology. One is a signal of some kind and the other is a very large or very energetic structure. The most obvious place to look for a signal is in the water-hole. Good article on that here. Because of the relatively low ...


5

What part of the EM spectrum was used in the black hole image?... Is it an image in visible light, infra-red or longer? Microwaves, (millimeter waves actually), and the hairy edge of far-infrared at a nominal frequency of 230 GHz or 1.30 mm wavelength, the bandwidth is roughly 2 to 6 GHz wide depending on how many channels of data were used to produce the ...


5

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 around the earth, it would be tremendously advantageous to collect from all of them, and the image resolution would improve with the addition of longer duration ...


5

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 (230-450GHz) to participate in the EHT array. For Asia Wikipedia lists the "Yevpatoria RT-70 radio telescope" as capable up to 300 GHz and located in western ...


4

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 it scan across the object again, and again. After a while you can re-construct an image from the scan lines in a similar way to analogue TV.


4

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 microwave region) which hits the surface of some body and bounces off to be received back on Earth by a second, separate radio telescope. Now, because a ...


4

Large radio telescope have pretty good pointing accuracy: the individual dishes of the VLA are accurate to about 10 arcsec. the giant Lovell telescope at Jodrell Bank has a similar accuracy. The second critical parameter is the beam width. Beam width depends highly on frequency: beamwidth = wave length/dish diameter When you use several dishes in an ...


4

You are right that the image is not a visible light image. It was taken using very, very short wavelength microwaves -- the wavelength is 1.3 mm which is only a bit shorter than the Far IR! I think you may be reading a bit too much into the word "photo" which, as you say, has the everyday meaning of "taken with a camera using lenses in visible light." I ...


4

How do radio telescopes gather information about visible light? They don't; the picture you saw all over the news was a false color image, where frequencies are shifted from the radio spectrum to the visible spectrum (blue meaning shorter radio wavelengths and red meaning longer radio wavelengths) and/or the intensities mapped to different colors (instead ...


4

tl;dr: The less complicated you want to make your dish, the closer to the equator you want to put it. Since you are asking about single craters I assume this question is about using a crater as a natural pre-form for a single, large dish antenna like Arecibo Observatory and FAST. On the Moon with no atmosphere or ionosphere nearly the whole sky is available ...


3

A common technique to estimate the beam position on the sky are so called pointing measurements. Ideally you try to use a radio point source with a known position on the sky. Scanning this point source with your radio beam will give maximum signal strength once the beam is centered on the object. By doing this for example as a cross-scan you are trying to ...


3

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 you need to be aware of any rusting and damage to the mesh that will distort your data. I'm mounting mine in my backyard on a 75mm steel pole 2 metres above ...


3

Yes, but not Earth-based ones. SHARAD (Shallow Radar) is an instrument on the Mars Reconnaissance Orbiter which performs subsurface imaging of Mars. Here is an image from Wikipedia of deposit layers on Mars's north pole, taken by SHARAD:


3

Radio telescopes cannot "see further" than optical telescopes but electromagnetic radiation in the range detected by radio telescopes may come from a further distance (i.e. from an earlier time) than detectable by optical telescopes and/or radio waves may penetrate things which are obscured at optical wavelengths. The classic example of the first case is ...


3

It is wasteful to sample with many bits because the signal to noise ratio at the ADC of a radio telescope is typically << 1, so using many bits would just be resolving noise. (An exception to this is when there is strong radio-frequency interference that needs to be resolved, but this is not a big problem for ALMA due to its location and observing ...


3

They're all mirrors, they just operate in different wavelength ranges. A wire fence could be a mirror if the wavelength is big enough. The surface is an easy problem to solve. Pick any material and do vacuum deposition with it on the substrate. It's the substrate, the base material that matters a lot - the thick part that keeps the shape. A metal mirror is ...


3

I'm going to compare the Murchison Widefield Array (MWA) to the Green Banks Telescope (GBT) just to pick two rather big projects. The first phase of the MWA featured 256 128 tiles and cost A$ 51 million. About the MWA: http://www.mwatelescope.org/telescope It saw first light in 2013. edit: the first phase comprised 128 tiles only but I could not find out ...


3

Shouldn't it be the other way around, that shorter wavelength telescopes like those in IR and the visible and UV generate more data because they have higher resolution per unit of aperture? This is a very interesting question! My answer is no, not currently, but someday it may be the case. Because we have big fast computer and fiber optic technology, we ...


3

That is what is done. This is shown in an old xkcd comic https://xkcd.com/54/ The curve shows the distribution of frequencies in the CMB, and by using the marked value of the maximum you can determine the value of T, the apparent (red-shifted) temperature of the CMB


2

I am not a professional astronomer, so take this answer with a grain of salt, but just from visiting a few facilities, I know some. For single dish applications, the 100m telescope in Effelsberg, Germany, uses a 7-beam receiver -- fewer than the Parkes array you mention, and I dont't know of any single dish setup with a larger number of beams. Regarding ...


2

The resolution of ADCs is inversely related to their conversion time. Getting more bits requires the signal to travel through more circuitry, which takes time. This is why you can have those high-quality audio ADCs with 18 or 20 bit resolution, which operate at frequencies in kHz range, meaning each conversion can take several milliseconds. At 4GS/s you only ...


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