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#39109 07/22/11 12:41 AM
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As the USA retired its Shuttle after 30 years of servicing the International Space Station today, the Russians placed the Worlds most powerful telescope into orbit yesterday.
'RadioAstron' or 'Spectrum-R' (as its named in Russia) is the most advanced and most powerful telescope ever built.

This Russian telescope reached its target orbit several hours after its launch the other day.
Although the Telelescope only has a 33ft diameter dish, it is expected to have a resolution 100,000 times better than the American-built Hubble Space Telescope, which was launched in 1990.

I think the reason for this incredible resolution is due to the fact that the Telescope (in a 211,000 thousand mile orbit) will be working with a number of Earth based telescopes and will be able to synthesize an apparent aperture of thousands of miles.

"Spectrum-R will be able to observe very remote parts of the universe and to receive a highly accurate data about various galactic phenomena, to study sources of radio waves from stellar phenomena, including pulsars, quasars, black holes, and neutron stars." said Viktor Khartov, the chief of the Lavochkin Research and Production Association, in an interview with the Russian news agency ITAR-TASS.

***My Thoughts
Hubble is an optical telescope, but it seems that Spectrum-R is a radio telescope
So talking about a resolution being 100,000 times better than Hubble is not really comparing like with like....is it?

http://www.dailygalaxy.com/my_weblog/201...ever-built.html


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"You will never find a real Human being - Even in a mirror." ....Mike Kremer.


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Radio telescopes of course look at a completely different part of the electromagnetic (EM) spectrum. So they tend to complement each other. Some things are seen better with an optical telescope, others with a radio telescope. So the new Russian telescope will provide a lot of new data that just couldn't be seen with the Hubble. By comparing the data from the 2 different views they will be able to learn a lot of new (and surprising) things.

The new telescope can work with ground based radio telescopes using long base interferometry to give high resolution. With a long enough separation, and this one will have a long separation between the space telescope and a ground based telescope, you can get amazing resolution. The biggest problem of course is that you get amazing resolution, but lose sensitivity, since you can't capture all of a wave front the way you can with a large optical telescope.

Bill Gill


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Thanks for the interesting info, Mike.

Originally Posted By: Mike Kremer
***My Thoughts
Hubble is an optical telescope, but it seems that Spectrum-R is a radio telescope
So talking about a resolution being 100,000 times better than Hubble is not really comparing like with like....is it?

http://www.dailygalaxy.com/my_weblog/201...ever-built.html

Yes, in a way it's certainly like comparing apples and pears isn't it, since it's incapable of detecting visible wavelengths. As Bill Gill says, the information received is different, and will complement that of other types of telescope. Still, I think the reference to 100,000x resolution does make sense - if the 'images' were to be transposed to the visible spectrum - e.g., as in TV broadcasts - the stated level of detail should be evident, right?
_______

Hi Bill
Originally Posted By: Bill
The biggest problem of course is that you get amazing resolution, but lose sensitivity, since you can't capture all of a wave front the way you can with a large optical telescope.

That sounds interesting but I don't know what it means. Could you explain it to a non-scientist?


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I have often wondered about using several space based telescopes as an interferometer. The cost would be large, but having a baseline of several thousand miles would seem to be highly useful. Using six telescopes (at least) arrayed so that any four would be on a plane would yield amazing images.


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Originally Posted By: redewenur
Originally Posted By: Bill

The biggest problem of course is that you get amazing resolution, but lose sensitivity, since you can't capture all of a wave front the way you can with a large optical telescope.


That sounds interesting but I don't know what it means. Could you explain it to a non-scientist?

What happens is rather simple. A solid reflector, such as on a radar antenna, will use the whole surface of the antenna as a reflective area. The resolution of the antenna depends on the diameter of the antenna, the sensitivity depends on the area. So if you build a solid antenna reflector the resolution and sensitivity will both go up as the size of the reflector goes up. If you build an interferometric antenna the separation between the 2 (or more) reflectors provides a resolution equivalent to that of a solid reflector , but the area is just the sum of the areas of the individual reflectors. So it will miss most of the radiation that would be caught by the solid reflector. I may not have stated that very well in my previous post.

I hope that clarifies the subject.

Bill Gill


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That's very clear, thanks Bill. So it simply means that the separation doesn't increase sensitivity. It was your choice of words "lose sensitivity" that had me wondering if there was more to it.


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I doubt there will be a flood of comments on this, so I won't make a new thread, but it's interesting enough to append here.

Longer-Baseline Telescopes Using Quantum Repeaters

Today's best optical and infrared interferometers use baselines of only a few hundred meters at most. The limitation is due to photon loss and uncontrolled phase shifts (due to vibrations, for example).

This proposes the future use of quantum entanglement to allow arbitrarily long baselines for optical and infrared interferometric arrays.

http://arxiv.org/PS_cache/arxiv/pdf/1107/1107.2939v1.pdf

"For radio frequencies, interferometry can be performed robustly today even between telescopes spread across the planet. Optical frequencies are much higher, so fewer photons arrive per second, making interferometry much more difficult. In telescope design, the arriving light is usually treated classically, but when the number of photons arriving is small, the quantum state of the light may become important. Thus, the fi eld of quantum information is well-suited to provide advances."


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I knew about the lack of comparable sensitivity, but the gain in resolution should allow for many of the objects that we are inferring are there to be more easily "seen". But the real question is if it is worth the cost.
Thanks for the clarifications.


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Originally Posted By: newtonsthird
I knew about the lack of comparable sensitivity, but the gain in resolution should allow for many of the objects that we are inferring are there to be more easily "seen". But the real question is if it is worth the cost.
Thanks for the clarifications.


[Quote=Mike Kremer]

Mike Kremer's reply.
Hi again- Newtons.Third
This is more of an update more than two years late. I am sorry about this ...but very interesting all the same...
Since this Russian Telescope "RadioAstron"
is using a projected Base Line of up to 20 Earth diameters.!!!
Its discoverys are somewhat technical-- so I am posting the
Russian 'RadioAstron' Newsletter No 19 (in English for all to read)
**************

"Record breaking results of AGN studies with RadioAstron
RadioAstron AGN survey continues to bring new exciting results.
Already many active galactic nuclei are detected at 18 and 6 cm up to the projected baselines of 20 Earth diameters.
As expected, results at longest projections are mostly delivered on baselines with the most sensitive ground radio telescopes { E elsberg (Germany), Arecibo and GBT (USA). In the same time, all of the ground radio telescopes participating in the AGN survey routinely result in positive
Space VLBI detections with Spektr-R.
Observations of 3C273 in January 2013 have broken the record of angular resolution announced last year by ground based 1.3 mm VLBI observations of 3C279 with APEX, SMA,and SMT.
The quasar was detected at 8.1 Earth diameters (7.6 G, fringe spacing 27 arcsec,see Figure 1) by the RadioAstron-GBT interferometer at 1.3 cm.
In the beginning of February 2013 RadioAstron has successfully observed the radio galaxy M87. These 1.3 cm observations were, for the rst time, supported from the ground by the
phased VLA. Angular resolution was comparable to the size of a shadow of the super-massive black in the center of M87, as predicted by the theory. The AGN working group is currently
reducing the data.
Pulsars at long interferometer baselines and interstellar medium
Several e ects accompany propagation of radio waves through an in homogeneous interstellar plasma: angular broadening, temporal smearing, distortions in radio spectrum, and intensity
http://www.asc.rssi.ru/radioastron/news/news_en.pdfmodulation (scintillations). These e ects are due to interference of separate radio rays scattered
or focused by random plasma inhomogeneities ("rough lenses"). Modern theoretical treatment of mentioned above scattering e ects predicts very low level of visibility amplitude for distant pulsars at long space-ground baselines of the RadioAstron mission. In contrast to these theoret-ical predictions strong visibilities were detected in observations of the distant pulsar B0329+54.
The observations were conducted with the GBT 100-m radio telescope of NRAO in Green Bank and RadioAstron space telescope at a frequency of 316 MHz. Distance to the spacecraft was about 275 000 km, and RadioAstron-GBT baseline projection was equal to 150 000 km. Fringe visibility amplitude as a function of fringe rate and delay is shown in Figure 2. For a source without scattering one should expect the presence of an isolated peak in the center of the picture. Instead, there is the presence of the whole ensemble of such peaks, each corresponding to certain combination of scattered rays. The observed structure is slowly varying with time at a scale of about 100 seconds. Thus, obtained results require a revision of our understanding of the structure of the interstellar plasma irregularities, and call for a new interpretation of the scattering of radio waves.Galactic water masers
Successful detection of interference fringes for the water maser in the high-mass star formation region W3 IRS5 located in the Perseus arm at a distance of 1.83 kpc is reported. Correlated msignal was obtained with space radio interferometer baselines between the orbiting 10-meter
antenna Spektr-R and the 40-m radio telescope in Yebes (Spain) and 32-m ground radio tele- scope in Torun (Poland). Observing session was held on 2 February 2013. The long projected
baseline length (5.4 Earth diameters, about 69 000 km) at the frequency of the water maser
transition (22 GHz) corresponds to an angular resolution of about 40 arcsec. This is equiva-lent to a linear resolution of 0.074 AU (11 million km) for W3 IRS5. This result represents the highest angular resolution ever obtained in observations of water masers. The observations are
part of a RadioAstron campaign to explore the existence of very compact maser structures.

With best regards!
Nikolai Kardashev (nkardash@asc.rssi.ru)
Yuri Kovalev (yyk@asc.rssi.ru)
To subscribe or un-subscribe to the Newsletter, use:
http://asc-lebedev.ru/index2.php?engdep=22
FINIS
*******************

PS. I NOW HAVE the Russian News Letter in English Plus Diagrams
(hopefully they will work for you all?)

http://www.asc.rssi.ru/radioastron/news/news_en.pdf

AND HERE. BUT USE THIS FIRST below!!!(It Works)

http://asc-lebedev.ru/index2.php





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"You will never find a real Human being - Even in a mirror." ....Mike Kremer.



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