Mapping the Radio Sky

Using a method called “Meridian Drift Scan Observation” it is possible to build up an image of the sky at radio frequency not visible using optical telescopes. As seen below.

The Radio Sky: Tuned to 408MHz Credit: C. Haslam et al., MPIfR, SkyView

Drift scans plot the sky line by line using the earths rotation from East to West then adjusting the antenna every 24 hours over a series of elevations separated by somewhat less than the angular beamwidth of your antenna. If you had a beamwidth of say 10 degrees, you would then lower the elevation by about five to seven degrees and making a strip chart for that elevation. You would continue the process until the beam was point a bit above your horizon and then combine the data to make a 2 dimensional map of the sky. In reality, there is quite a bit more to do this, but this is the basic Idea.

Here are some more examples:

The Infrared Sky (and more)