
Quick Review of the Itty Bitty Radio Telescope
#1
Posted 01 September 2024 - 05:07 AM
Click here to view the article
- Mark SW, Dobs O Fun and Craigar like this
#2
Posted 02 September 2024 - 09:02 AM
Here is a site that explains the whats and whys about what is being detected:
https://physicsopenl...radio-emission/
This detects at 12,200 to 12,700 MHz and it is the solar black body radiation at 6000K, enhanced a bit (probably by the high temperature corona).
It is acting as a microwave thermometer, detecting the Sun's heat. But this is not fundamentally different from when we look at the Sun through solar filters -- we are observing the Sun's thermal emissions in the visible band.
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#3
Posted 02 September 2024 - 02:18 PM
Thanks for the additional info. Do you have one?
#4
Posted 07 September 2024 - 11:48 PM
Thanks for the additional info. Do you have one?
No, but this might enter my queue for a club outreach device.
- michaelcaba likes this
#5
Posted 08 September 2024 - 04:59 AM
seen one demonstrated
very interesting
- michaelcaba likes this
#6
Posted 08 September 2024 - 01:54 PM
No, but this might enter my queue for a club outreach device.
Yes, it works great for outreach! It's very simple, so as a day to day tool for an amateur astronomer its kind of a 1 trick pony, i.e, once you have done it a few times you have seen all it has to offer. But the 1 trick is really good for outreach. Highly recommended.
#7
Posted 08 September 2024 - 03:51 PM
Do you have any quick visual of what you've graphed out with any quick blurbs on what some specific, significant detections mean?
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#8
Posted 08 September 2024 - 07:04 PM
Do you have any quick visual of what you've graphed out with any quick blurbs on what some specific, significant detections mean?
In terms of space objects, it only detects the Sun. Probably the best visual out there is at this link: https://www.youtube....h?v=jyAgRg9EJGU
#9
Posted 10 September 2024 - 06:24 AM
Thanks. I learned quite a bit from reading this review and then looking up a bit more about amateur radio-astronomy. Turns out you can go a bit further and not for a lot of extra cost. You do need more yard area to strategically position a couple of dipole antennas and then you can check up on how Jupiter is doing in addition to the Sun. (Just more stuff to mow around though. )
The NASA Radio Jove Project home is: https://radiojove.gsfc.nasa.gov
and the basic DIY Radio Jove kit is $220 + shipping. The DIYer has to supply his own four mounting poles and guy wires for the ends of the two dipoles and their height could go up to 20ft depending on your latitude and the rest depends on Jupiter's declination and elevation.
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#10
Posted 10 September 2024 - 11:09 AM
In terms of space objects, it only detects the Sun. Probably the best visual out there is at this link: https://www.youtube....h?v=jyAgRg9EJGU
You might be able to pick up the Moon too. (Particularly interesting because you are actually detecting the thermal radiation from the Moon, not the reflected radiation from the sun). Here is my version with a slightly bigger dish
http://www.threehill...astronomy_1.htm
Cheers
Robin
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#11
Posted 10 September 2024 - 11:47 AM
You might be able to pick up the Moon too. (Particularly interesting because you are actually detecting the thermal radiation from the Moon, not the reflected radiation from the sun). Here is my version with a slightly bigger dish
http://www.threehill...astronomy_1.htm
Cheers
Robin
Interesting. I did not know that about the Moon. I will have to try that some night.
#12
Posted 10 September 2024 - 02:26 PM
I wonder what software is used to construct images out of the readings taken?
- michaelcaba likes this
#13
Posted 11 September 2024 - 05:06 AM
I wonder what software is used to construct images out of the readings taken?
The radio telescope is like a one pixel camera. A picture is built up by taking a series of scans and plotting out the intensity.
Also If you look at a particular frequency eg neutral Hydrogen you can use the doppler shifts eg to map out the arms in the milky way which are moving at different velocities relative to us
Here is an example of nice little project to map the milky way.
http://parac.eu/projectmk3.htm
Cheers
Robin
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#14
Posted 27 October 2024 - 04:34 PM
This is a lot like one the SETI League brought to a SF Convention maybe 20-30 years ago. They claimed it was inspired by a small fusion reactor I had brought to an earlier con. They demonstrated that it could detect body heat. However, the dish was too small to detect SETI signals well. They recommended a 12-ft satellite dish for that. Their system was based on a nice digitally-controlled ICOM microwave receiver that could be set up to scan a band in the microwave spectrum, essentially making a spectrum analyzer. The SETI League is an amateur group, not to be confused with the SETI Institute. I believe their designs for their SETI-specific radiotelescope are on-line. The 12-ft dish is intended to be capable of detecting the "WOW!" event. https://en.wikipedia...iki/Wow!_signal
The SETI League SF Convention one was specifically a public outreach device, and it got a lot of attention.
Facebook friend Mike Geogiopolis spent a career working with NASA gadgets, and appears to have an especially nice homebrew radio telescope in the works.
- michaelcaba likes this
#15
Posted 27 October 2024 - 04:45 PM
Ah, here it is.
Stealing an idea from Tom Ligon (see the last two Images of the Week), SETI League executive director H. Paul Shuch set up a simple demonstration radio telescope at the Arisia science fiction convention in Boston the second weekend of January. This device, based upon a Ku-band Direct Broadcast Satellite antenna and low-noise block downconverter, is capable of detecting only the very strongest astrophysical sources. Nevertheless, its presence in the exhibit hall drew in the crowds for Paul's SETI talk.
20 March 1999
In a page of "pictures of the week", 1999. Also in there are many mentions of their more serious amateur SETI observatories. http://www.setileagu...tos/pixwk99.htm
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#16
Posted 28 October 2024 - 12:25 PM
This is a lot like one the SETI League brought to a SF Convention maybe 20-30 years ago. They claimed it was inspired by a small fusion reactor I had brought to an earlier con. They demonstrated that it could detect body heat. However, the dish was too small to detect SETI signals well. They recommended a 12-ft satellite dish for that. Their system was based on a nice digitally-controlled ICOM microwave receiver that could be set up to scan a band in the microwave spectrum, essentially making a spectrum analyzer. The SETI League is an amateur group, not to be confused with the SETI Institute. I believe their designs for their SETI-specific radiotelescope are on-line. The 12-ft dish is intended to be capable of detecting the "WOW!" event. https://en.wikipedia...iki/Wow!_signal
The SETI League SF Convention one was specifically a public outreach device, and it got a lot of attention.
Facebook friend Mike Geogiopolis spent a career working with NASA gadgets, and appears to have an especially nice homebrew radio telescope in the works.
Interesting. Thanks for sharing.
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#17
Posted 04 November 2024 - 02:53 AM
Many thanks. I translated and forwarded your post to Facebook Turkish Amateur Astronomy group (with 22k members).
- michaelcaba likes this
#18
Posted 04 November 2024 - 02:23 PM
Many thanks. I translated and forwarded your post to Facebook Turkish Amateur Astronomy group (with 22k members).
You are welcome!
#19
Posted 04 November 2024 - 06:10 PM
My daughter, her friends in high school, and I built a horn antenna that can detect 21cm Hydrogen line following these 2 articles. The first paper is brief but you get idea what the project looks like and the second one has everything you need to complete the project. The second paper is the courtesy from SARA (Society of Amateur Radio Astronomers).
https://lweb.cfa.har...SposterPDF2.pdf
https://www.radio-as...al-Feb-2019.pdf
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#20
Posted 05 November 2024 - 05:10 PM
My daughter, her friends in high school, and I built a horn antenna that can detect 21cm Hydrogen line following these 2 articles. The first paper is brief but you get idea what the project looks like and the second one has everything you need to complete the project. The second paper is the courtesy from SARA (Society of Amateur Radio Astronomers).
Great stuff! The Scope in a Box by SARA can also detect the 21cm hydrogen line.
#21
Posted 05 November 2024 - 06:31 PM
Great stuff! The Scope in a Box by SARA can also detect the 21cm hydrogen line.
The price tag of this is mostly beyond most of people can afford.
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#22
Posted 08 November 2024 - 12:02 PM
The price tag of this is mostly beyond most of people can afford.
I think the price for the Scope in a Box is $350 at this link:
https://www.radio-as.../scope-in-a-box
The tripod in that kit is pretty flimsy, so an upgrade to something else will add to the cost. I upgraded to an Explore Scientific Twilight I, which sells new for $350. So going that route, the price jumps to $700. Nonetheless, the setup with the upgraded mount works very well, is sturdy and the antenna itself is easy to point. Hope that helps.
#23
Posted 20 December 2024 - 01:19 PM
Here is a site that explains the whats and whys about what is being detected:
https://physicsopenl...radio-emission/
This detects at 12,200 to 12,700 MHz and it is the solar black body radiation at 6000K, enhanced a bit (probably by the high temperature corona).
It is acting as a microwave thermometer, detecting the Sun's heat. But this is not fundamentally different from when we look at the Sun through solar filters -- we are observing the Sun's thermal emissions in the visible band.
Can you please show me the formula to convert 12,200 to 12,700 MHz to 6000K? Thank you.
#24
Posted 20 December 2024 - 01:33 PM
Can you please show me the formula to convert 12,200 to 12,700 MHz to 6000K? Thank you.
It sounds like what you are looking for is Planck's law. Every body at any temperature emits photons at every possible frequency, just in varying amounts. The peak of emission is given by Wien's displacement law, and for bodies at 6000 K apparent temperature (like the Sun) that frequency is in green light -- where the human eye is most sensitive. This is not a coincidence. As shown in the chart on the Open Physics site the Sun is about a million times dimmer at 12.5 GHZ.
The radiotelescope would actually be more interesting if it operated at 0.1 to 1 GHZ because solar emissions in this band vary enormously with the solar cycle.
https://en.wikipedia...ki/Planck's_law
https://en.wikipedia...isplacement_law
#25
Posted 10 January 2025 - 12:37 PM
It sounds like what you are looking for is Planck's law. Every body at any temperature emits photons at every possible frequency, just in varying amounts. The peak of emission is given by Wien's displacement law, and for bodies at 6000 K apparent temperature (like the Sun) that frequency is in green light -- where the human eye is most sensitive. This is not a coincidence. As shown in the chart on the Open Physics site the Sun is about a million times dimmer at 12.5 GHZ.
The radiotelescope would actually be more interesting if it operated at 0.1 to 1 GHZ because solar emissions in this band vary enormously with the solar cycle.
https://en.wikipedia...ki/Planck's_law
Thank you. I think I got it.