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8

Interesting idea. I think the answer is both yes and no -- yes with a manufactured dish but no in the crater's raw state. The Arecibo telescope sits in a natural crater, but adds a dish which has a couple of important things required by a radio dish: a radio-reflective surface a specific curvature, classically parabolic, but also shaped low surface ...


8

@Arne is right in his answer about two things, that the most suitable frequency for Jovian amateur radio is 20.1 MHz, and that this is a 15 meter wavelength. However, the antenna can actually be half the wavelength, and amateur radio astronomers have had good results listening to all kinds of Jovian sounds, including detecting occultations of its many moons ...


5

All electromagnetic radiation from a point source - which a normal radio transmitter is - propagates according to the inverse square law which means that the intensity of the signal is inversely proportional to the square of the distance. This happens on earth and in deep space equally. So this will mean that for any signal there will be a distance at which ...


4

The resolution/error box. Radioastronomy has always been hindered by the resolution, because it is inversely proportional to the size of the telescope and making larger telescopes (even with interferometry) is not always easy. No amount of modern technology can substitute for a large effective diameter. (When I say effective I'm including interferometry ...


4

I think the image you posted is not quite reallistic. On it, objects are just inverted from some radius on, while what you can expect from a real black hole seen from near enough is a combination of these: a) an accretion disc b) a companion being sucked c) Hawking's radiation d) X-Ray burst from the poles (really starting out of the event horizon) You ...


4

A parabola does indeed focus over a broad frequency range. The lower limit is determined by the dish diameter, the upper by the construction (mesh size, parabolic accuracy etc.). The collector placed at the focal point may be a simple dipole or other fixed frequency antenna, or more commonly, a waveguide that leads the collected signals to a low noise ...


3

Since the astronomers are using radio telescopes and not optical telescopes, I'd like to point out why they are doing so - The centre of the Milky Way is a very dusty place. Wavelengths from the millimeter to optical get easily absorbed by all this dust, so it's very difficult to see the centre of the galaxy in the optical spectrum. But radio waves do not ...


3

The first thing to consider is that the area of a beam will, over long distances, diffuse. The best situation we can hope for is a diffraction-limited system, where this diffusion is minimized thus maximizing our received signal. That is, in theory we have a perfectly collimated transmission beam that neither diverges nor converges. In practice, we are ...


3

The StarGazers lounge featured a radio kit article for Jupiter radio astronomy. The same article is also featured over at the Radio Group of BritAstro. It seems that 20.1 MHz is the suitable frequency for amateurs observing Jupiter. I am far from being an expert for radio astronomy, but for a small source such as Jupiter, I would assume that you need a big ...


3

The first thing to notice is that the Local Interstellar Cloud, in which the Sun is evolving right now, is a fairly diffuse region, with a typical density of about one to a few particles per cubic centimeters. Clouds with such low density are actually mostly atomic; as you can see on this plot (Snow & McCall 2006, adapted from Neufeld et al. 2005): It ...


2

1MW of transmitted power is very modest by RADAR terms, to give one example. Thus, you probably need to establish what exactly your professor means by "brightest" (may it be a specific wavelength or point in time, or some other definition). Otherwise, there's no reason to believe that Arecibo transmission was any special or outstanding from radio engineering ...


2

The pointing is not a fundamental problem with the suggested design: The suggested trajectory is designed to include a Sun flyby as the last flyby. This ensures an asymptotically radial trajectory away from the sun after the flyby, hence maintaining the pointing relative to the sun. The proper motion of the observed object may be some challenge, but the ...


2

Could large craters on the moon be used as reflective lenses for radio signals? You'd have to line the surface with something reflective to microwaves, like a metallic mesh, or similar materials. Secondly, the shape of the crater is probably not quite ideal, so it would have to be adjusted a little, carved up a bit in various places. But it's a good ...


2

Tired light has been used as an explanation before, whereby light loses energy whilst travelling through space---a sort of drag effect. I don't think anyone actually supports it nowadays, though.


1

2SB is Dual Sideband, as opposed to DSB - Double Sideband. Here are a couple of papers you might find relevant and interesting: a 2SB upgrade replacing a DSB a paper that mentions the advantages of 2SB over DSB


1

I agree that the crater needs to be lined, but you also have the problem of maintaining a satellite in stationary orbit above the crater. Nearly impossible unless the crater is on the equatorial plane. Also, a stationary satellite around the moon would be influenced by the Earth, so you would need to burn fuel to keep the satellite in position.


1

This can actually mean a couple of different things, but in the case of steering an MWA tile, Jeremy is quite correct. Each tile has a 'beamformer' box that all of the individual antenna cables plug into. This box physically delays each signal appropriately (by having a longer path to go through for more delay) based on the signals sent to it for each ...


1

Check out the Design Overview and the Antenna/Beamformer page on the MWA website. The basic idea is that the signal arriving at an antenna is delayed in the circuitry, which makes it seem to the processing engine like the tile is being tilted in a particular direction.


1

It cannot be said correctly, since we humans have hardly traveled to the moon and sent space probes to explore other planets in our solar system. So, theoretically anything might be possible. I'm trying to be a bit practical here. The only man made object that has gone really far is Voyager 1, which is at a distance of 18.7 billion kilometers (125.3 AU) from ...


1

another problem for an amateur looking for black holes is that the telltale signature of a black hole, coming in the form of continuous or bursts of X-rays and gamma rays, cannot be observed from the surface of the Earth, because the atmosphere (thankfully) protects us from that sort of stuff. So that is why you need to go in space, or on the surface of a ...



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