On 31 March 2013, not long after it was discovered, astronomers observed Comet Siding Spring with Herschel. This was just one month before the observatory exhausted its supply of liquid helium coolant and ceased to collect data. When Herschel observed it, the comet was about 6.5 AU from the Sun. The observations were performed following a proposal for Director’s Discretionary Time from Peter Mattisson from the Stockholm Amateur Astronomers (STAR) in Sweden.

These three images show emission from the dust in the coma surrounding the nucleus of Comet C/2013 A1 – also known as Comet Siding Spring – as observed at three different far-infrared wavelengths with ESA's Herschel space observatory. Credit: SA/Herschel/PACS/Cs. Kiss et al. 2014

These three images show emission from the dust in the coma surrounding the nucleus of Comet C/2013 A1 – also known as Comet Siding Spring – as observed at three different far-infrared wavelengths with ESA’s Herschel space observatory. Credit: SA/Herschel/PACS/Cs. Kiss et al. 2014