Figure 1: Big Ear simulation showing the flux curves for four modeled radio sources. The animation illustrates how the telescope operated by combining signals from its two beams (red and blue) through subtraction to produce the expected observed flux (black curve). The beam pattern is derived from a two-dimensional sinc function, resulting in the visible sidelobes in the plot. The horn rectangles indicate the FWHM in right ascension and declination. The beam response, however, extends beyond these bounds, and the null-to-null width is roughly 2.3× the FWHM. The integration time of this sample (also referred to as the time constant) is 3 s, matching the value used for the paper strip-chart output. However, the digital data were recorded at 10-second intervals. Credit: Arecibo Wow!

Figure 2: Same as Figure 1, but with added noise consistent with the strip chart output (~55 mJy) and superposed random RFI, which is largely canceled by the observed signal after the subtraction of the negative from the positive horn. Credit: Arecibo Wow!