WASHINGTON — The first satellites of a Chinese broadband constellation are significantly brighter than those of Western systems, posing a new challe

Brightness of first Chinese broadband constellation satellites alarms astronomers

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2024-10-05 22:30:01

WASHINGTON — The first satellites of a Chinese broadband constellation are significantly brighter than those of Western systems, posing a new challenge for astronomers.

In a paper posted on the arXiv preprint server Sept. 30, a group of observational astronomers reported on observations of a set of 18 Qianfan, or “Thousand Sails,” satellites launched in August. The satellites are the first of a constellation that may ultimately consist of more than 14,000 satellites.

The study found that the brightness of the satellites ranges from magnitude 8 when low in the sky to magnitude 4 when nearly overhead. That makes the satellites, at those higher elevations, bright enough to be seen by the naked eye — which can see objects down to magnitude 6 in dark skies — and well above the threshold of magnitude 7 recommended by professional astronomers it mitigate interference with major groundbased observatories.

“Qianfan satellites are brighter than magnitude 6 except when observed at low elevations in the sky,” the astronomers note in the paper. “So, they will adversely impact professional and amateur astronomical activities unless the operators mitigate their brightness.”