Measuring Distance with Time

gravywavy
gravywavy
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RE: Could we be seeing

Message 13925 in response to message 13923

Quote:
Could we be seeing Amateur GW Astronomers one day?
GW telescopes (in as much as a dish antenna is a "telescope") could be engineered using new methods of construction to allow both a good sensitivity of detection and physically smaller size.


That is a useful analogy.

How many amateur radio astronomers are there? All the backyard astronomers I know of use optical telescopes, as part of the attraction for them is looking at the sky. But that is more of a personal impression than good stats.

We can certainly imagine microwave astronomy observatories in the reach of individuals.

What is less likely is amateur radio astronomers at longer wavelengths as for a given resolution the antenna size is proportional to wavelength. As you go to loneger wavelengths radio astonomy needs serious amounts of real estate, so that even if the equipment is cheap only the very rich could set up in their backyard.

Applying these thoughts to GW

After GW have certainly been observed, even more money will become available for imnproving detectors, and that will mean prices dropping in the ong run. GW may become affordable to indivduals.

The other question is signal to noise - the noise is the normal vibrations around any site, machines, traffic, seismo, etc. The signal mist be roughly proportional to the size of detector. My guess is that even if the detecting equipment comes down in price, signal to noise issues will mean gw research is still confined to large sites. That would make amateur gw astronomy a province of the very rich, like long-wave radio astronomy.

~~gravywavy

Chipper Q
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Every amateur astronomer

Every amateur astronomer knows what it's like to miss an event because the clouds got in the way, and so the most exciting thing to me about GW's is that nothing gets in the way.

barkster
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RE: What is less likely is

Message 13927 in response to message 13925

Quote:
What is less likely is amateur radio astronomers at longer wavelengths as for a given resolution the antenna size is proportional to wavelength. As you go to loneger wavelengths radio astonomy needs serious amounts of real estate, so that even if the equipment is cheap only the very rich could set up in their backyard.


What if someone invented a "dish@home" progam where we could do distributed/arrayed radio astronomy by sharing time on our satelite TV dishes? :-)

Or did someone at Microsoft already patent that idea?

"No, I'm not a scientist... but I did stay at a Holiday Inn Express."

Chipper Q
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RE: Or did someone at

Message 13928 in response to message 13927

Quote:

Or did someone at Microsoft already patent that idea?


What, like it's not obvious to someone skilled in the art? :)
[SETI's Allen Telescope Array Update page, with links to the gen/tech overviews]

barkster
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RE: RE: Or did someone

Message 13929 in response to message 13928

Quote:
Quote:

Or did someone at Microsoft already patent that idea?

What, like it's not obvious to someone skilled in the art? :)
[SETI's Allen Telescope Array Update page, with links to the gen/tech overviews]


Yes... but they are building their own "dedicated" array.

I'm talking about a dish@home project that can use MY satelite dish (or YOURS)when it's not being used for TV. Imagine many hundreds of dishes being used to search the night sky with an combined aperature that spans the continent.

"No, I'm not a scientist... but I did stay at a Holiday Inn Express."

Chipper Q
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RE: I'm talking about a

Message 13930 in response to message 13929

Quote:
I'm talking about a dish@home project that can use MY satelite dish (or YOURS)when it's not being used for TV. Imagine many hundreds of dishes being used to search the night sky with an combined aperature that spans the continent.


Oops! Now I see what you're suggesting. I think that's a dog-gone-good idea, barkster. But how much overhead is there for the dish owner? I think at least the tracking & timing hardware and the labor to install it, and also the interface hardware (presumably including signal filtering/conditioning components) for connection to the PC. Since dishes are currently installed on both vertical and horizontal surfaces, aiming the array would be limited to a smaller portion of the sky. Hopefully others (with expertise) will have comments, but it sounds workable to me.

MarkF
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It is a rainy day. To

It is a rainy day.
To correlate the results from multiple receivers you must meet two criteria. One you must know the relative position of each receiver to within a fraction of the signals wave length. Two each receiver must have a time base (ie clock) which is stable and correlated to every other to within a fraction of the inverse of the frequency of the signal.

barkster
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RE: It is a rainy day. To

Message 13932 in response to message 13931

Quote:
It is a rainy day.
To correlate the results from multiple receivers you must meet two criteria. One you must know the relative position of each receiver to within a fraction of the signals wave length. Two each receiver must have a time base (ie clock) which is stable and correlated to every other to within a fraction of the inverse of the frequency of the signal.

Phhhttt.... EASY!! ;-)

1. A fraction of the wavelength of "low freq" GR is well within GPS error... Is it not?

2. We could all buy one of those self setting "nuclear" wall clocks!! I seen 'em for sale pretty cheap on TV!

(I'm sure it's not quite that easy... but one day, maybe "home" technology will catch up with the current scientific world. Seemed like a nice idea.)

"No, I'm not a scientist... but I did stay at a Holiday Inn Express."

barkster
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Ok... that last post was

Ok... that last post was obviously a bit of sarcasm, and I know I somehow jumped from radio astronomy to GW detection in posting it.... but let me fly this one past you...

Again, just an idea.

Let's say we could afford the overhead for a bunch of home grown radio telescopes, and we solved problems 1 and 2 below...

What would the resolution be? Good enough perhaps to lock onto a constant and reliable radio source that a very nice and sharp reference "image" could be developed?

And what if a gravity wave(s) passed us and distorted the array (as it does LIGO... but the "arms" in this case are MUCH larger)... what would happen to the reference "radio astronomy" image as the wave passed, and could cyclic properties (like pulsar) be measured in the image variations from the reference?

That's it!... I'm spent.

"No, I'm not a scientist... but I did stay at a Holiday Inn Express."

Chipper Q
Chipper Q
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Here's a link to the Square

Here's a link to the Square Kilometer Array (SKA) home page. It's a radio telescope designed to have more than 30 times greater effective collecting area than the largest telescope ever built.

One really neat thing about an arrayed-dish technique is the ability to multiply the number of directions in which observations are made *in the hardware*, without multiplying the number of dishes. It's literally possible to look in many directions at once, with adequate hardware.

Would off-the-shelf optical telescope controllers work for aiming the satellite TV dishes, and if so, would this add a significant amount of surface area to the SKA?

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