Building a Radio Telescope : Part 1


A Project i've been putting off for quite a while is to try and build a Radio Telescope. I've been reading up about Radio Telescopes for about 2 years but i could never get my ass moving to start building one. And well, i've finally started working on one.

But firstly, let me tell you what Radio Astronomy is. The Wiki article is pretty detailed but basically, radio astronomy is observing the skies and studying the energy earth receives in the radio spectrum. I didnt say 'observing the night skies' because radio waves can be detected day or night, unlike in visible astronomy where the sun ruins the day time observations.

Listing out the process of Radio Astronomy -

  • Radio Sources - which emit energy in the radio spectrum.
  • Receivers - which are able to pick up these signals.
  • Data Analysis - for you to be able to infer something about the sources from this data. 

  • Radio Sources -

The emissions from Sun, Jupiter, The Galactic Disc and a couple of close by galaxies (Cassiopeia) basically form the strong radio sources when seen from earth. And there are different kinds of processes which are involved in these radio emission like Synchrotron radiation, Bremsstrahlung etc etc but that is for the more serious.


  • Receivers -

So, day or night, we receive emissions in the radio spectrum from different parts of the sky. And then comes detection. Any kind of antenna can be used to pick up these signals, even the basic Yagi Antenna or the now common Dish TV antenna receivers.And since there are emissions in different bands of the radio spectrum, you will almost always be able to pick up something.

The most easiest to build and operate is a Dipole Antenna, which are built to observe emissions of specific frequencies. One of the more popular, amateur dipole radio antenna which is being used for Radio Astronomy can be found here, it is a project funded by NASA and it is basically a Dipole Antenna designed to observe emissions specific to Jupiter, at the frequency of 20.1MHz. The link will give you further instructions about building the radio dipole, data analysis and further reading. And like i said, this is one of the more popular amateur receivers being used now a days for radio astronomy.


  • Data Analysis - 
So, now that we know what sources there are in the sky and we have an antenna to pick up their signals, we need to be able to decipher the signals these sources are sending to be able to understand something about them.

The frequency of the signals from these sources can be used to decipher how far away they are from us, the strength of the signal will tell us the amount of matter present at the source (which is causing the emissions) etc. You should read up the wiki article on Astronomical Spectroscopy to have a better idea on how to use this data.

I've tried to put it as simply as i could. But the next time, i am not going to hold back. Im going to go total nerd on you. I will write on what exactly i am trying to build, how i intend to record the signals from the antenna and process the data through MATLAB.

And last but not the least - you ask why i do this?
Because i wanna look at the stars in the day time as well, 8 hours in the night is not enough! :D
Until next time...

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