What sources are in the Northern Hemisphere?
Are they detectable by 3.7-meter Radio Telescope?
What kind of spectrum do they have?
Are they discrete or spatially distributed?
Now, in this section, my major aim is to answer each of these important questions which a amateur radio astronomer must seek their answers before designing his or her small radio telescope. To answer these qestions, the three most important parameters one need to consider are following-
1. Source Flux
2. Spectrum
3. Angular size
In the coming sections, I will show how each one of them are important while targeting a particular type of radio source. Now, before getting into the more technical aspect, let us review the basic physics behind radio sources.
The type of sources which we observe in the radio spectrum is quite different than what we observe in the visible night sky. In contrast to our sky is periodically become dark and bright as night and day transition happens, radio sky is always dark. the object we see are mostly bright radio galaxies(which are millions of light years away), supernova remnants, neutral and ionized hydrogen clouds and also, in terms of other molecular and atomic transition which we can study via their spectral lines studies. In our solar system too, we can see sun which is indeed the brightest radio source we can observe on earth but it is much dimmer in radio as compare to what we see in visible band. we can also see the Moon ( it thermally radiates in radio) and also, the Jupitar (via its non-thermal radiation).other planets too radiate in radio band but because of the very small intensity, we are unable to see them with moderate telescopes ( moderate meaning 1- 15 meter RT).