Image Processing Reference
Figure3.11 Aitoff projection of the visible sky. (CourtesyofAxelMellinger)
Figure3.12 Block diagram of radio telescope and celestial source. The telescope has a
narrow field of view (the “beam”) that scans the source.
single detection element, since the scenes they image do not change on the time
scales of a scan; and therefore a multielement detector is unnecessary. The antenna
assembly is scanned back and forth across the target to build up an image, much as
an inkjet printer builds up an image by scanning back and forth across a piece of
paper, forming an image line by line.
The disadvantage of scanning an image pixel-by-pixel is that the scene has
to stay still during the scan; but this is not a serious problem when recording
astronomical image data, since the scene is unchanging over very long time scales.