A clearer view of the night sky

A solution to the problem of infrared interference affecting land-based telescopes is reported in this week’s Nature Communications. Scientists present results from on-sky tests that demonstrate the ability of a photonic filter to block out this unwanted light. This technology may provide new research opportunities for infrared astronomy with current and future telescopes. Emissions in the upper atmosphere cause extreme brightness that poses an obstacle to studying the infrared night sky from Earth. Although this problem can be overcome by launching telescopes to observe space from beyond the atmosphere, this solution is very expensive. In light of new developments in photonics, Joss Bland-Hawthorn and colleagues have developed a filter that can suppress lines of interfering emissions. Test on the night sky show that the bright lines are successfully removed without affecting spectral coverage.