M51, VLA
M51 is a spiral galaxy in the constellation of Canes Venatici. It lies at a distance of about 37 million light years. Images at most wavelengths show two galaxies, the larger of which is M51 while the smaller of the two is known to astronomers as NGC5195.

M51 has also been observed with the Very Large Array, a collection of radio telescopes situated in New Mexico. By comining the signals from 27 telescopes, astronomers can synthesise a much bigger telescope.

Image credit: VLA