Small Radio Telescope
undergraduates to gain experience with interferometry, the
junior members of the ObsCosLab began a project to build three Small
Radio Telescopes (SRTs) to map the neutral Hydrogen of the Milky Way.
21 cm Emission
Hydrogen consists of one
proton and one electron. When the spins of the proton and electron are
the atom has a slightly higher energy than when the spins are opposite.
When an electron in the lowest orbital changes from spin aligned to
misaligned the energy of the atom decreases by a small energy E. In
order to conserve energy, the a photon must be emitted with frequency
f=E/h=1420 MHz, corresponding to a wavelenght of 21cm. Our radio
telescopes are designed to be sensitive to a small band of frequencies
centered at 1420 MHz.
single telescope, an interferometer combines the signals from
an array of telescopes to obtain measurements with much higher
resolution. A typical interferometer, a "multiplying interferometer,"
nominally consists of receivers, pre-amplifiers, and a correlator that
multiplies the signals together.
and Program from MIT Haystack, MA. Their webpage
and the srt page is http://www.haystack.mit.edu/edu/undergrad/srt/index.html