Starship Asterisk*

Left shows an image of a piece of sky observed with the hitherto best calibration technique. Right shows the same piece of sky with the new technique. More detail is visible, and what were once large, blurry patches now appear as single points. (c) LOFAR/Groeneveld et al.

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Radio telescopes have an advantage over optical telescopes, in that radio telescope can be used even in cloudy conditions here on Earth. That’s because the longer wavelengths of radio waves can pass through clouds unhindered. However, some wavelengths are still partially obscured by portions of Earth’s atmosphere, especially by the ionosphere which traps human-made Radio Frequency Interference (RFI).

Astronomers have developed a new calibration technique that allows them to take sharp images in low radio frequencies — between 16 and 30 MHz — for the first time, bypassing the influence of the ionosphere. The astronomers say this will allow them to study things like plasmas emanating from ancient black holes and perhaps even detect exoplanets that orbit small stars.

The technique was developed by an international team of researchers led by astronomers from Leiden University in the Netherlands.

“It’s like putting on a pair of glasses for the first time and no longer seeing blurred,” said Christian Groeneveld from Leiden University, who led the research.
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