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Getting Started
Radio Spectrum
VLF Solar
Magnetometry
Simple Radio Astronomy
Radio Jove
Meteor Reflections
Hydrogen Line
Gamma Ray and HEP
Glossary

Radio Spectrum

Most amateur astronomers observe in Visible light. The electromagnetic spectrum encompasses a vast scope, starting almost at Direct Current and with frequencies up to 2.4×1023 Hz (Gamma rays).


(image courtesy wikipedia)

As can be seen from the figure, visible light comprises a tiny fraction of the entire EM spectrum - everything else is considered to be fair game for radio astronomers

However, not all this radiation can actually penetrate the atmosphere. Additionally, much of the spectrum is used by commercial bodies - for example, television, mobile phones, data communications etc. In fact, there is actually very little left that is potentially usable yet unused. Because of this, certain bands of frequencies are protected and these should be considered if serious observations are planned. It is not necessary to stick to these bands though, in fact it can be much more rewarding and easier making use of existing consumer hardware and living with the interference. This is potentially no worse than that most optical astronomers have to put up with - observing through a light polluted sky.

Radio Astronomy Protected Frequencies

There are a number of internationally protected frequencies that are sererved for the use of Radio Astronomers. However, not all these are globally honoured. For example, the band 73 - 74.6MHz is peculiar to the USA and Canada whereas it is unrecognised in the UK. It should also be noted that the 608 - 614MHz band will lose its protection in the UK from September 2012.

Frequency band Status Radio astronomy use
13.36 - 13.41 MHz    
25.55 - 25.67 MHz    
37.5 - 38.25 MHz   Continuum observations
73 - 74.6 MHz   Solar wind observations.
Continuum observations.
80.5 - 82.5 MHz   Pulsar observations
150.05 - 153 MHz   Continuum observations.
Pulsar observations.
Solar observations.
322 - 328.6 MHz   Continuum observations.
VLBI
406.1 - 410 MHz   Continuum observations.
Pulsar observations.
608 - 614 MHz   Continuum observations.
VLBI
1400 - 1427 MHz   Spectral line observations
21cm hydrogen line
1660 - 1660.5 MHz   VLBI
1660.5 - 1668.4 MHz   VLBI
Line observations.
Continuum observations.
1668.4 - 1670 MHz    
1718.8 - 1722.2 MHz    
2655 - 2690 MHz   Continuum observations
2690 - 2700 MHz    
3260 - 3267 MHz    
3332 - 3339 MHz    
3345.8 - 3352.5 MHz    
4800 - 4990 MHz   Continuum observations
4990 - 5000 MHz   Continuum observations.
VLBI
5000 - 5030 MHz   VLBI
6650 - 6675.2 MHz    
10.6 - 10.68 GHz   Continuum meausurements.
VLBI
10.68 - 10.7 GHz   Continuum observations.
VLBI
14.47 - 14.5 GHz   Spectral line observations.
VLBI
15.2 - 15.35 GHz   VLBI
15.35 - 15.4 GHz   Continuum observations.
VLBI
22.01 - 22.21 GHz   Spectral line observations
Water line
22.21 - 22.5 GHz   Spectral line observations
Water line.
22.91 - 22.86 GHz   Spectral line observations
Methyl Formate
Ammonia
23.07 - 23.12 GHz   Spectral line observations
23.6 - 24.0 GHz   Spectral line observations
Continuum observations
Ammonia line
31.2 - 31.3 GHz   Continuum observations
31.3 - 31.5 GHz   Continuum observations
31.5 - 31.8 GHz   Continuum observations
36.43 - 36.5 GHz   Spectral line observations
Hydrogen cyanide
Hydroxil
42.5 - 43.5 GHz   Spectral line observations
Silicon monoxide and many other lines
48.94 - 49.04 GHz   Spectral line observations
Carbon monosulphide
51.4 - 54.25 GHz    
58.2 - 59 GHz    
72.77 - 72.91 GHz   Spectral line observations
Formaldehyde line.
86 - 92 GHz   Spectral line observations.
Continuum obserations
92 - 94 GHz   Spectral line observations.
Diazenylium and many other lines.
95 - 100 GHz   Spectral line observations.
Continuum observations.



The majority of Amateur Radio Astronomy observations are usually performed at less than 12GHz. Higher frequencies are deemed to be very exotic requiring very specialist construction and measurement techniques

Resources

Committee on Radio Astronomy Frequencies

Copyright 2010 British Astronomical Association