projects, by Jeffrey Lichtman, SARA
radio spectrum is by far less used than its visible counterpart. It is a
challenge for an amateur to get information from this so-called "noise from
space" and be interested in such activities. The next list gathers
potential subjects which confirm however there are a lot of thing to do even
using small infrastructures.
Some of them are ambitious but well in the range of
the capabilities of an amateur radio telescope.
parallel to these activities if you can do visual observation of the same areas,
you can try to correlate these observations with radio records. Then you will
begin to understand where is the true utility of your work.
the most powerful radiosource, the Sun is of course our best observation
subject. Your equipment only requests a broad beamed radio telescope, optionaly
fixed on an equatorial mount. In a period of a few months you can detect the
periodicity of the signals induced by its rotational rate. With some accuracy
you can also detect the non-uniformity of this rate according to the solar
electrical storms we can heard in the HF bands between 18-24 MHz are of very
high intensity and may be detected with communications type receivers tuned to
an inactive portion of this band. Antennas used are identical with any antenna
system resonant at this frequency. The noises are so powerful that the antenna
need not necessarily be resonant.
time to time, when severe storms are expected on Jupiter, NASA
provides a link to its receivers through the Internet.
shape of the Milky Way
by its power, the Milky Way is also a subject of great interest. Its shape is
easily discernable by a simple radio telescope. The easiest method to detect it
is using a drift scan. While the sky rotates, the angular distance to the
galactic center will vary and the signal strenght will be modulated according to
the angular separation from the galactic core.
an more accuracy system the inclination of the galactic equator to the ecliptic
can also be detected.
Jansky's pioneer work. With a radio telescope relatively sensitive you can
operate in the Very High Frequency bands of microwaves to detect the temperture
of the subject. The electromagnetic energy of the blackbody is everywhere
present and can easily be recorded. This more demonstrative use of the radio
telescope can be tested on various subjects, from a human body to the nigh sky
or in presence of a warm object. Then you can compare your output signal
with the true temperature of the subject analyzed.
application of appropriate formulas and knowing the characteristics of the
antenna pattern you can also estimate the temperature of the Sun and the Moon.
clouds emission can be detected using a quite sensitive antennna and an
oscilloscope display (completed with a ramp voltage generator and a
downconverter stage). As the sources can be very short is sizes, the bandwidth
of your receiver must be narrow enough to resolve hydrogen lines but not too
much to preserve the sensibility. The frequency must also be steady to be able
to pratice some calibration and in the bast cases to observe the doppler shoft
of the lines.
very interesting activity give you the chance to map the relative motions of
bright hydrogen clouds distributed all over the sky.
energy pulses or HEP have been reported for years by amateurs with some spots in
the center part of our Milky May. Recent gamma rays observations have revealed
some of these HEP have indeed been correlated with observations did by amateurs.
But not all are accociated with galactical sources. Therefore a confirmation of
their origin is required as well as the coorelation between their radio signal
and a potential gamma burst. This work requests the cooperation of many
amateurs, widely separated, sharing their observations and correlating them with
the simultaneous observations from professionals.
course such project request a high accurate timing calibration but works fine
with a standard amateur beam able to track the celestial sphere drift along the
will find more information in the litterature dealing with amateur radio
astronomy as listed in the previous pages or in my URLs.
How does a Radio Telescope Work?, CSIRO
Weak signal communication
(radiotelescopes and accessories)
SARA (Society of Amateur
Build a Homebrew Radio Telescope (PDF), WA8SME, QST, June 2009
SETI : Project BAMBI
Radio Group at UFRO
Radio Telescope (SRT).
to Radio astronomy