2: Radio Astronomy Fundamentals
We started on Chapter 2. Particular
websites of interest are:
(History of radio astronomy)
(Discovery of the Cosmic Microwave Background Radiation)
(Little Green Men)
(Discovery of Pulsars)
(Indirect detection of gravitational waves)
learned about power, spectral power,
brightness, brightness distribution, and flux density. Do you recall
We considered an antenna looking at part of a source brightness
distribution and figured out what we would measure.
An antenna is, in most cases, a one-pixel camera. We went in
more detail through the differences and
similarities between the convolution integral as a mathematical
description of the output of a linear filter and the convolution
integral as a
mathematical description of what is measured by an antenna when
scanning a source. Difference is that the source function is
convolved with the mirror
image of the beam pattern whereas
the mirror image is not taken of the impulse response.
We looked at
different combinations of source brightness distribution and
beam pattern. Today was also the second and last day where we had a
double lecture to make up for the cancelled lectures.
focussed on the blackbody characteristics, antenna
temperature, spectral power and noise.
Assignment #2 was returned, and we discussed the
problem sets in detail. We continued with Chapter 2.
We finished Chapter 2 by considering how Penzias and
Wilson could be so sure that they detected a residual temperature
of about 3K
that could not be accounted for in terms of a contribution from their
horn antenna and receiver set-up. Click here for
the latest satellite to
measure the 3K background radiation