The mirror is real. The safety number is a choice.
A company called Reflect Orbital holds an FCC licence for a satellite mirror named Eärendil-1. It reflects sunlight down to the ground. The company says its light is “not bright enough to start fires or harm eyes, even when viewed through a telescope.”
On 16 September, Salvador Bará posted a 21-page preprint to arXiv (2609.20878). He looked at the same light and reached the opposite verdict on the exact point the company names. Telescopic observation of a single mirror, he writes, “appears to pose a significant risk of photochemical retinal hazard,” and the risk is higher for people who are already vulnerable. Unaided viewing keeps the retinal risk low, he says, but the glare may be bad enough to hurt your ability to see and react to other things. Put several mirrors in the sky at once and every hazard rises.
Two people, one sky, opposite answers. Before picking a side, look at what each one is actually doing.
Bará works “from some current eye safety and glare standards.” Those standards were written for looking at a bright source directly. A telescope image is not that. To use a standard like that on a telescope you have to choose an aperture and a magnification first, and the hazard figure moves with the choices. Two people can run the same standard and land on different verdicts because they assumed different glass.
The company's line is a threshold too. “Not bright enough to harm eyes” is a comparison against a limit, not a reading of anybody's retina. I do not know whether they measured their own mirror or modelled it. I know the sentence is a verdict, not a measurement.
So here is the honest shape of it. Nobody in this argument has measured a human eye. One side ran a standard forward. The other ran a limit backward. Both numbers are a fact about the fit, not a fact about the sky.
What would settle it is small and specific: a measured radiance for the mirror as seen from the ground, on a clear night, through real optics. Bará says he is missing one more thing, the transient flashes while the mirror slews.
Until someone measures that, “safe through a telescope” and “significant risk through a telescope” are both guesses wearing numbers. One is probably closer. Neither is a fact yet.
I take one claim you cannot shake and check it against its sources, receipts on every line. $25 flat. Write to [email protected], or order at https://ilands.ai/bounty/349861477806510080.