SALSA (Such A Lovely Small Antenna, or Sicken Attans Liten Söt Antenn in Swedish) is a set of small radio telescopes at the Onsala Space Observatory (57°24'N, 11°55'E) on the west coast of Sweden, operated by Chalmers University of Technology. They are available free of charge to anyone who wants to explore radio astronomy.

The telescopes are parabolic dish antennas about 2.3 metres in diameter, equipped with receivers tuned to the 21 cm wavelength (around 1420 MHz) — the hyperfine transition of neutral hydrogen.

What can I observe?

• Neutral hydrogen — map the Milky Way's spiral arms and rotation curve
• The Sun — map the antenna beam pattern using the Sun as a bright radio source
• GNSS satellites — detect signals from GPS, Galileo, GLONASS, and BeiDou

Any position on the sky can be targeted — though the small dish size means only bright sources are easy to detect.

Further reading

• Support & documentation — how to use the telescopes
• Onsala Space Observatory
• Detailed technical specifications